Quick soft start control method and device for switching power supply

Abstract

The invention discloses a rapid soft start control method and device for a switching power supply. The method comprises the following steps: determining a target voltage output by a soft start preprocessing circuit in a steady state according to a preset standard voltage, a preset standard current and a load resistance value of a resistive load; determining a target duty ratio corresponding to a switching tube of the soft start preprocessing circuit in a steady state according to the target voltage and a preset input voltage of the switching power supply; a first control signal is sent to the pulse width modulation circuit, and the duty ratio of the switching tube is adjusted to the maximum duty ratio; monitoring that the real-time output voltage of the soft start preprocessing circuit is increased to the target voltage through a voltage sampling circuit; and a second control signal is sent to the pulse width modulation circuit, and the duty ratio of the switching tube is adjusted from the maximum duty ratio to the target duty ratio, so that rapid soft start of the switching power supply is realized and a steady state is reached. According to the invention, the soft start time of the switching power supply can be obviously shortened, and the switching power supply can rapidly reach a stable working state after soft start.

Description

Technical Field

[0001] This application relates to the field of power supply circuit control technology, and in particular to a fast soft-start control method and device for a switching power supply. Background Technology

[0002] In switching power supply control, output soft-start control is a core technology and a crucial factor in ensuring its reliability. It effectively suppresses large inrush currents and excessive voltage overshoots generated during power supply startup, protecting power switching transistors and load devices, and ensuring the system smoothly enters normal operating conditions. This control is achieved by gradually increasing the duty cycle or changing the frequency through software control, allowing power transmission to increase slowly. However, due to the uncertainty of the load, different loads have different requirements for startup characteristics. Typically, a loop PID control is used to achieve soft starting, gradually increasing the duty cycle from 0 to the target value while simultaneously allowing the voltage to rise smoothly to the set value. However, the entire adjustment process takes a relatively long time.

[0003] With the increasing demand for rapid soft-start applications, such as in industrial control and communication equipment, devices need to be able to quickly restart and recover when power outages occur due to grid fluctuations, ensuring stable and reliable output. In the increasingly popular field of DC fast charging stations for electric vehicles, users expect rapid charging to shorten waiting times, requiring charging modules to quickly provide high-power and stable DC power for direct vehicle charging. For these applications requiring rapid soft start, traditional soft-start control methods are insufficient due to excessively long adjustment times. Therefore, a rapid soft-start control solution is needed to shorten the soft-start duration. Summary of the Invention

[0004] This application provides a fast soft-start control method and apparatus for a switching power supply. By estimating the load resistance of the internal circuit of the switching power supply, the final steady-state operating parameters of the circuit are predicted in advance. Then, the duty cycle is directly set to the maximum duty cycle to drive the voltage and current to rise rapidly. Once the circuit output voltage reaches the predicted steady-state operating voltage, the duty cycle is immediately switched to the predicted steady-state duty cycle. At this time, loop control is performed, and the circuit converges quickly through PID regulation, so that the circuit output is stabilized in the target operating range, that is, stabilized near the final steady-state operating parameters, thereby significantly shortening the soft-start time of the switching power supply.

[0005] In a first aspect, embodiments of this application provide a fast soft-start control method for a switching power supply, applied to the controller of the switching power supply. The switching power supply includes a soft-start preprocessing circuit, which includes a resistive load, a switching transistor, a voltage sampling circuit, and a pulse width modulation circuit. The pulse width modulation circuit is connected to the switching transistor and is used to adjust the duty cycle of the switching transistor. The voltage sampling circuit is connected to the output terminal of the soft-start preprocessing circuit. The controller is connected to both the voltage sampling circuit and the pulse width modulation circuit. The method includes: The target voltage output by the soft-start preprocessing circuit in steady state is determined based on the preset standard voltage, preset standard current, and the load resistance value of the resistive load. The target duty cycle of the switching transistor in steady state is determined by the soft-start preprocessing circuit based on the target voltage and the preset input voltage of the switching power supply. A first control signal is sent to the pulse width modulation circuit, the first control signal being used to adjust the duty cycle of the switching transistor to the maximum duty cycle; The real-time output voltage of the soft-start preprocessing circuit is monitored by the voltage sampling circuit. The real-time output voltage was monitored to increase to the target voltage; A second control signal is sent to the pulse width modulation circuit. The second control signal is used to adjust the duty cycle of the switching transistor from the maximum duty cycle to the target duty cycle, so as to realize the fast soft start of the switching power supply and reach a steady state.

[0006] Secondly, embodiments of this application provide a fast soft-start control device for a switching power supply, applied to the controller of the switching power supply. The switching power supply includes a soft-start preprocessing circuit, which includes a resistive load, a switching transistor, a voltage sampling circuit, and a pulse width modulation circuit. The pulse width modulation circuit is connected to the switching transistor and is used to adjust the duty cycle of the switching transistor. The voltage sampling circuit is connected to the output terminal of the soft-start preprocessing circuit. The controller is connected to both the voltage sampling circuit and the pulse width modulation circuit. The device includes: The processing unit is used to determine the target voltage output by the soft-start preprocessing circuit in steady state based on the preset standard voltage, the preset standard current, and the load resistance value of the resistive load; and to determine the target duty cycle corresponding to the switching transistor of the soft-start preprocessing circuit in steady state based on the target voltage and the preset input voltage of the switching power supply. The transmitting unit is used to send a first control signal to the pulse width modulation circuit, the first control signal being used to adjust the duty cycle of the switching transistor to the maximum duty cycle; The processing unit is also configured to monitor the real-time output voltage of the soft-start preprocessing circuit through the voltage sampling circuit; and to monitor the real-time output voltage increasing to the target voltage. The transmitting unit is further configured to send a second control signal to the pulse width modulation circuit. The second control signal is configured to adjust the duty cycle of the switching transistor from the maximum duty cycle to the target duty cycle, so as to achieve fast soft start of the switching power supply and reach steady state.

[0007] Thirdly, embodiments of this application provide an electronic device including a processor, a memory, and one or more programs, the one or more programs being stored in the memory and configured to be executed by the processor, the programs including instructions for performing the steps in the first aspect of embodiments of this application.

[0008] Fourthly, embodiments of this application provide a computer-readable storage medium having a computer program / instructions stored thereon, which is executed by a processor to implement the steps of the method described in the first aspect.

[0009] As can be seen, in this embodiment, the controller first determines the target voltage output by the soft-start preprocessing circuit in steady state based on the preset standard voltage, preset standard current, and the load resistance value of the resistive load; then, it determines the target duty cycle corresponding to the switching transistor of the soft-start preprocessing circuit in steady state based on the target voltage and the preset input voltage of the switching power supply; next, it sends a first control signal to the pulse width modulation circuit, which is used to adjust the duty cycle of the switching transistor to the maximum duty cycle; secondly, it monitors the real-time output voltage of the soft-start preprocessing circuit through the voltage sampling circuit; thirdly, it monitors the increase of the real-time output voltage to the target voltage; finally, it sends a second control signal to the pulse width modulation circuit, which is used to adjust the duty cycle of the switching transistor from the maximum duty cycle to the target duty cycle, so as to realize the fast soft start of the switching power supply and reach steady state. Thus, compared to existing soft-start schemes that gradually increase the duty cycle from 0 to the target value, this application directly sets the duty cycle to the maximum duty cycle, driving the voltage and current to rise rapidly; once the circuit output voltage reaches the predicted steady-state operating voltage, the duty cycle is immediately switched to the predicted steady-state duty cycle, thereby significantly shortening the soft-start time of the switching power supply and enabling the switching power supply to quickly reach a stable operating state after soft start. Attached Figure Description

[0010] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0011] Figure 1 This is a schematic diagram of the structure of a switching power supply provided in an embodiment of this application; Figure 2 This is a flowchart illustrating the steps of a fast soft-start control method for a switching power supply provided in an embodiment of this application. Figure 3 This is a circuit diagram of a two-level phase-shifted full-bridge topology circuit provided in an embodiment of this application; Figure 4 This is a schematic diagram of the output voltage curve of a switching power supply provided in an embodiment of this application; Figure 5 This is an overall flowchart of a fast soft-start control method for a switching power supply provided in an embodiment of this application; Figure 6 This is a functional unit block diagram of a fast soft-start control device for a switching power supply provided in an embodiment of this application; Figure 7 This is a structural block diagram of an electronic device provided in an embodiment of this application. Detailed Implementation

[0012] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present application.

[0013] The terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish different objects, not to describe a specific order. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to these processes, methods, products, or apparatuses.

[0014] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0015] In the embodiments of this application, "and / or" describes the relationship between associated objects, indicating that three relationships can exist. For example, A and / or B can represent the following three situations: A exists alone; A and B exist simultaneously; B exists alone. Among them, A and B can be singular or plural.

[0016] In this embodiment, the symbol " / " can indicate that the preceding and following objects are in an "or" relationship. Alternatively, the symbol " / " can also represent a division sign, i.e., performing a division operation. For example, A / B can mean A divided by B.

[0017] In the embodiments of this application, "equal to" can be used with "greater than" and is applicable to technical solutions used when "greater than" is used; it can also be used with "less than" and is applicable to technical solutions used when "less than" is used. When "equal to" is used with "greater than", it is not used with "less than"; when "equal to" is used with "less than", it is not used with "greater than".

[0018] With the increasing demand for rapid soft-start applications, such as in industrial control and communication equipment, devices need to be able to quickly restart and recover when power outages occur due to grid fluctuations, ensuring stable and reliable output. In the increasingly popular field of DC fast charging stations for electric vehicles, users expect rapid charging to shorten waiting times, requiring charging modules to quickly provide high-power and stable DC power for direct vehicle charging. For these applications requiring rapid soft start, traditional soft-start control methods gradually increase the duty cycle from 0 to the target value while simultaneously allowing the voltage to rise smoothly to the set value. However, this adjustment time is too long to meet the demands, thus necessitating a rapid soft-start control solution to shorten the soft-start time.

[0019] To address the aforementioned issues, this application provides a fast soft-start control method and apparatus for a switching power supply. The embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0020] Please see Figure 1 , Figure 1 This is a schematic diagram of a switching power supply provided in an embodiment of this application. Figure 1 As shown, the switching power supply 100 includes a controller 110 and a soft-start preprocessing circuit 120. The soft-start preprocessing circuit 120 includes a resistive load 121, a switching transistor 122, a voltage sampling circuit 123, a current sampling circuit 124, and a pulse width modulation circuit 125. The pulse width modulation circuit 125 is connected to the switching transistor 122, and the controller 110 is connected to the soft-start preprocessing circuit 120.

[0021] The switching power supply 100 is a power supply device that achieves efficient energy conversion through the switching of high-frequency switching transistors. Its core function is to provide a stable output voltage / current to the load. In this application, it adopts a layered architecture of controller 110 and soft-start preprocessing circuit 120, which not only undertakes the core task of energy conversion, but also achieves a fast, smooth, and safe startup process through built-in soft-start logic, avoiding voltage / current surges during startup that could damage the load or the power supply itself.

[0022] The controller 110 is the "intelligent decision-making center" of the switching power supply 100, and is typically composed of chips such as a microcontroller (MCU) and a digital signal processor (DSP). It does not directly participate in energy transfer, but focuses on data processing, algorithm calculation, and command issuance. Specifically, it receives voltage signals from the voltage sampling circuit 123 and current signals from the current sampling circuit 124, executes core algorithms such as load resistance calculation, steady-state parameter prediction, and PID regulation, and then issues control commands to the pulse width modulation circuit 125. It is the "command center" of the entire fast soft-start process, determining the efficiency, accuracy, and stability of the soft start.

[0023] The soft-start preprocessing circuit 120 serves as the "execution carrier" of the switching power supply 100, acting as the hardware unit for achieving rapid soft-start. All practical actions related to soft-start (energy transfer, signal sampling, and duty cycle adjustment) are completed within this circuit. It uses the resistive load 121 as its service target, the switching transistor 122 as its energy valve, the voltage sampling circuit 123 and current sampling circuit 124 as sensing units, and the pulse width modulation circuit 125 (PWM circuit) as its control actuator. Through the coordination of these sub-modules, it transforms the controller 110's instructions into actual voltage / current outputs, serving as a crucial bridge connecting decision-making and execution.

[0024] Among them, the resistive load 121 is the "power supply object" of the switching power supply 100 (such as a resistive element in a resistance heating device or communication equipment), and is also the "characteristic adaptation target" of this application. Its core characteristic is that the voltage and current have a linear relationship (which conforms to Ohm's law V=I×RL). This characteristic is the physical basis for the calculation of load resistance and the prediction of steady-state parameters in this application. Only based on the binding relationship between the voltage V and the current I of the resistive load 121 can the load resistance be obtained through voltage / current sampling under a small duty cycle, and then the target voltage and duty cycle can be predicted. This is one of the prerequisites for the fast soft-start logic to be valid.

[0025] The switching transistor 122 acts as the "energy valve" of the soft-start preprocessing circuit 120, typically employing high-power semiconductor devices such as MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistors) and IGBTs (Insulated-Gate Bipolar Transistors). Its core function is to receive the drive signal from the pulse-width modulation circuit 125 and control energy transfer through high-frequency on / off actions: when on, input energy is transferred to the resistive load 121; when off, energy transfer is interrupted. The ratio of its on / off time (duty cycle) directly determines the amount of energy transferred per unit time, making it the core actuator for regulating the output voltage / current.

[0026] Among them, the voltage sampling circuit 123 is the "voltage sensor" of the soft-start preprocessing circuit 120. It collects the circuit output voltage in real time through components such as resistor voltage dividers and operational amplifiers, and converts the high-voltage signal into a low-voltage signal that the controller can recognize. The current sampling circuit 124 is the "current sensor". It collects the output current through shunts, Hall elements and other means, and converts the high-current signal into an electrical signal that the controller 110 can process. Together, they provide the controller 110 with real-time voltage and current data to support the core logic such as load detection, steady-state prediction and PID regulation.

[0027] The pulse width modulation circuit 125 is the "duty cycle control actuator" of the soft-start preprocessing circuit 120, and is usually composed of a PWM chip and a drive circuit. Its core function is to receive the instructions issued by the controller 110, generate a "high-frequency pulse drive signal with adjustable duty cycle", and output the signal to the control terminal of the switching transistor 122 (such as the gate of a MOSFET). By adjusting the "conduction time ratio" of the pulse, the switching rhythm of the switching transistor 122 is controlled, and the precise adjustment of the duty cycle (such as small duty cycle, maximum duty cycle, target duty cycle) is finally achieved. It is the "link" connecting the instructions of the controller 110 and the actions of the switching transistor 122.

[0028] As can be seen, in this embodiment, the hierarchical design of controller decision-making and soft-start preprocessing circuit execution, combined with real-time sensing of voltage / current sampling circuit, energy switching control of switching transistors and precise duty cycle adjustment of PWM circuit, not only achieves fast soft start in resistive load scenarios, but also avoids start-up impact through load detection, steady-state prediction and PID adjustment, ensuring stable output voltage / current, thus balancing the efficiency, safety and accuracy of soft start.

[0029] The following is combined Figure 2 The fast soft-start control method for switching power supplies provided in the embodiments of this application will be further described.

[0030] Please see Figure 2 , Figure 2 This is a flowchart illustrating the steps of a fast soft-start control method for a switching power supply provided in an embodiment of this application. Figure 2 As shown, the method includes the following steps: Step S210: Determine the target voltage output by the soft-start preprocessing circuit in steady state based on the preset standard voltage, preset standard current, and the load resistance value of the resistive load.

[0031] The preset standard voltage refers to the "rated voltage reference" required for the load to work normally, and is also the "safe upper limit of voltage" for the power supply output (for example, 12V for sensors and 50V for heating loads). This ensures that the output voltage does not exceed this value and avoids damage to the load due to overvoltage.

[0032] The preset standard current refers to the "maximum safe current reference" that the load can withstand, which is also the "safe current limit" of the power supply output (e.g., no more than 5A for resistive loads and no more than 8A for small motors), ensuring that the output current does not exceed this value and avoiding overload and burnout.

[0033] In one possible embodiment, determining the target voltage output by the soft-start preprocessing circuit in steady state based on a preset standard voltage, a preset standard current, and the load resistance of the resistive load includes: determining a target preset standard value that should preferentially satisfy the resistive load between the preset standard voltage and the preset standard current; determining that the target preset standard value is either the preset standard voltage or the preset standard current; if the target preset standard value is determined to be the preset standard voltage, then determining the preset standard voltage as the target voltage; and if the target preset standard value is determined to be the preset standard current, then obtaining a reference voltage output by the soft-start preprocessing circuit in steady state based on the product of the preset standard current and the load resistance; and determining the smaller voltage between the reference voltage and the preset standard voltage as the target voltage.

[0034] Furthermore, if the target preset standard value is determined to be the preset standard voltage, then after determining the preset standard voltage as the target voltage, if the current value obtained based on the ratio of the preset standard voltage to the load resistance is greater than the preset standard current, then the target voltage is obtained according to the product of the load resistance and the preset standard current, instead of using the preset standard voltage as the target voltage, so as to avoid the circuit current exceeding the limit.

[0035] Understandably, different resistive loads have different core requirements. For example, precision electronic equipment (sensors, chips) needs to prioritize voltage stability (to avoid voltage fluctuations damaging components). In this case, it is necessary to prioritize meeting the preset standard voltage and use the preset standard voltage as the target voltage to determine the target current of the circuit in steady state. On the other hand, resistance heating devices and motor starting loads need to prioritize current limitation (to avoid current overload burning out the load). In this case, it is necessary to prioritize meeting the preset standard current and use the preset standard current as the target current to determine the target voltage of the circuit in steady state.

[0036] In a specific embodiment, the target preset standard value that needs to be prioritized for the resistive load between the preset standard voltage and the preset standard current can be determined based on the load type of the resistive load. For example, for loads with high voltage stability requirements, such as precision electronic components and sensors, the preset standard voltage is prioritized; for loads sensitive to current overload, such as resistance heating devices and motor starters, the preset standard current is prioritized. Alternatively, it can be determined based on configuration instructions pre-issued by the user, automatically identified based on the rated operating parameters of the load, or based on preset rules for the application scenario of the switching power supply. For example, in industrial control scenarios, the preset standard current is prioritized by default, while in civilian electronic equipment scenarios, the preset standard voltage is prioritized by default. The specific implementation method can be flexibly selected according to actual needs, which is not the focus of this application.

[0037] For example, assuming the preset standard voltage is 50V and the preset standard current is 5A, the priority has been determined by the load type (resistive loads such as precision electronic components prioritize voltage, while resistive loads such as resistance heating prioritize current), and the resistance values ​​of the resistive loads have been detected as 15Ω (electronic components), 8Ω (heating load), and 12Ω (heating load); if it is a precision electronic component load (voltage priority), then the preset standard voltage of 50V is directly determined as the target voltage. At this time, the corresponding current is 50V / 15Ω≈3.3A≤5A, which meets the current safety threshold; if it is a resistance heating load (current priority), when the load resistance is 8Ω, the reference voltage is first calculated as 5A×8Ω=40V. Since 40V<50V, 40V is taken as the target voltage (to avoid current overload); when the load resistance is 12Ω, the reference voltage is 5A×12Ω=60V. Since 60V>50V, 50V is taken as the target voltage (to avoid voltage exceeding the limit). The final determined target voltage can take into account both the core requirements of the load and safety constraints.

[0038] It should be noted that this application only provides one method for determining the target voltage output by the soft-start preprocessing circuit in steady state based on a preset standard voltage, a preset standard current, and the load resistance value of the resistive load. This application does not limit other reasonable determination logic and execution steps. For example, the target voltage determination logic can be optimized by introducing additional parameters such as the rated power of the load and the operating temperature threshold, or a step-by-step strategy of "first calculating the voltage range according to a preset ratio, and then selecting the final value in combination with priority" can be adopted. Alternatively, in a current-priority scenario, the comparison weight between the reference voltage and the preset standard voltage can be dynamically adjusted to adapt to special load requirements. As long as a safe and suitable steady-state target voltage can be determined based on the characteristics of the resistive load and the constraints of the preset standard voltage and preset standard current, it does not deviate from the core concept and protection scope of this application.

[0039] In one possible embodiment, the soft-start preprocessing circuit further includes a current sampling circuit connected to the output terminal of the soft-start preprocessing circuit, and the controller is connected to the current sampling circuit. Before determining the target voltage output by the soft-start preprocessing circuit in steady state based on a preset standard voltage, a preset standard current, and the load resistance value of the resistive load, the method further includes: sending a third control signal to the pulse width modulation circuit, the third control signal being used to adjust the duty cycle of the switching transistor to a preset reference duty cycle; obtaining a reference voltage output by the soft-start preprocessing circuit at the preset reference duty cycle through the voltage sampling circuit; obtaining a reference current output by the soft-start preprocessing circuit at the preset reference duty cycle through the current sampling circuit; and obtaining the load resistance value of the resistive load based on the ratio of the reference voltage and the reference current.

[0040] The preset reference duty cycle is a small duty cycle to avoid large voltage / current impacts on the load. After the soft-start preprocessing circuit stabilizes at the preset reference duty cycle, voltage and current are sampled. Finally, based on Ohm's law for resistive loads (load resistance = reference voltage / reference current), the actual resistance of the load is accurately calculated.

[0041] It should be noted that this application only provides one method for determining the load resistance value of a resistive load. This application does not limit other reasonable methods based on the characteristics of the resistive load, such as using the rated voltage and rated power of the load to inversely deduce the resistance value (RL= To improve accuracy, methods such as averaging sampling data under multiple different reference duty cycles, introducing temperature compensation algorithms to correct resistance drift caused by ambient temperature, using dedicated impedance measurement chips to directly acquire load impedance, or completing resistance calibration through an independent pre-detection module before soft start are all acceptable as long as they can accurately obtain the actual resistance value of the resistive load to support the subsequent calculation of target voltage and duty cycle.

[0042] As can be seen, in this embodiment, the resistive load resistance value is accurately obtained by probing with a small duty cycle and combining Ohm's law. Then, the priority is flexibly set based on the load type and application scenario. The core logic is "voltage priority for direct locking and current priority for parameter calculation and selection of the smaller value". Combined with the overvoltage and overload fallback mechanism, it not only adapts to the core requirements of different resistive loads (such as voltage stabilization of precision components and current limiting of heating loads), but also ensures the safety and accuracy of the steady-state target voltage. At the same time, it is compatible with multiple parameter acquisition and judgment methods, which improves the versatility and reliability of the solution and provides key parameter support for subsequent target duty cycle calculation and fast soft start.

[0043] Step S220: Determine the target duty cycle of the switching transistor in steady state of the soft-start preprocessing circuit based on the target voltage and the preset input voltage of the switching power supply.

[0044] In one possible embodiment, determining the target duty cycle of the switching transistor in steady state of the soft-start preprocessing circuit based on the target voltage and the preset input voltage of the switching power supply includes: determining the voltage ratio between the target voltage and the preset input voltage of the switching power supply; obtaining the preset voltage gain coefficient and preset energy transfer efficiency corresponding to the soft-start preprocessing circuit; and obtaining the target duty cycle of the switching transistor in steady state of the soft-start preprocessing circuit based on the product of the voltage ratio, the preset voltage gain coefficient, and the preset energy transfer efficiency.

[0045] It is understandable that the core principle of a switching power supply is to "adjust the energy transfer ratio by the duty cycle". Ideally (without loss and without topology gain), the ratio of the output voltage to the input voltage is equal to the duty cycle (such as the ideal formula for Buck topology: output voltage Vo = duty cycle D × input voltage Vin, which leads to duty cycle D = output voltage Vo / input voltage Vin).

[0046] However, different topologies have different voltage conversion gains, resulting in different ideal formulas. For example, the ideal voltage formula for a phase-shifted full-bridge topology is output voltage Vo = duty cycle D × input voltage Vin × n (where n is the transformer turns ratio), with a gain coefficient G = 1 / n. For a Buck topology, G = 1 (no transformer, direct voltage division). Furthermore, actual circuits contain losses (switching transistor conduction losses, transformer copper / iron losses, diode voltage drops, etc.), causing the actual output voltage to be lower than the ideal value. Therefore, an efficiency η (typically 0.8~0.95) is introduced for correction, essentially "increasing the duty cycle to compensate for losses." For example, if the ideal duty cycle is 0.4, and the efficiency is 0.8, then the actual required duty cycle is 0.4 / 0.8 = 0.5 to achieve the target output voltage.

[0047] Specifically, taking the phase-shifted full-bridge topology as an example, and considering its isolated voltage conversion characteristics, the influence of transformer turns ratio, and actual energy loss, the final formula for the target duty cycle is derived as follows: D_wt=(Vo_wt / Vin)×(1 / G)×(1 / η); Where D_wt is the target duty cycle of the primary-side switch of the phase-shifted full-bridge topology, Vo_wt is the target output voltage of the secondary side of the phase-shifted full-bridge topology, Vin is the input DC voltage of the primary side of the phase-shifted full-bridge topology, G is the inherent voltage gain factor of the phase-shifted full-bridge topology, which is only related to the transformer turns ratio. Define the number of turns on the primary side of the transformer as Np and the number of turns on the secondary side as Ns, then G=Ns / Np. η is the actual energy transfer efficiency of the phase-shifted full-bridge topology (η= secondary side output power Po / primary side input power Pi), which needs to take into account actual losses such as switch turn-on / turn-off losses, transformer copper / iron losses, and secondary rectifier voltage drop losses.

[0048] It should be noted that this application only provides one method for determining the target duty cycle of the switching transistor in steady state of the soft-start preprocessing circuit based on the target voltage and the preset input voltage of the switching power supply. This application does not limit other reasonable calculation logic based on the characteristics of the circuit topology and the actual operating conditions. For example, topological parasitic parameters (such as leakage inductance and parasitic capacitance) can be introduced for fine correction, a dynamic adjustment strategy of "first calculating the duty cycle range and then iteratively optimizing it in combination with real-time output voltage feedback" can be adopted, a special calculation model can be designed to adapt the nonlinear gain characteristics of special topologies such as resonant phase-shifted full bridges, the mapping relationship between duty cycle and voltage under different operating conditions can be fitted by machine learning algorithms to improve the adaptation accuracy, or a weighted average method can be used to fuse the voltage ratio and compensation coefficient in multi-input voltage scenarios. As long as the duty cycle of the switching transistor that enables the soft-start preprocessing circuit to stably output the target voltage can be determined based on the target voltage and the input voltage of the switching power supply, it does not deviate from the core concept and protection scope of this application.

[0049] As can be seen, in this embodiment, the calculation logic of the product of voltage ratio, topology gain coefficient and energy transfer efficiency accurately adapts to the characteristics of different circuit topologies and corrects the actual losses, ensuring that the target duty cycle enables the soft-start preprocessing circuit to stably output the target voltage. At the same time, it is compatible with various extended calculation methods such as parasitic parameter correction and feedback iterative optimization, taking into account the accuracy of duty cycle calculation, topology adaptability and scenario universality, and providing reliable control parameter support for the duty cycle switching of subsequent fast soft start.

[0050] Step S230: Send a first control signal to the pulse width modulation circuit. The first control signal is used to adjust the duty cycle of the switching transistor to the maximum duty cycle.

[0051] Understandably, after completing load resistance detection and target voltage and target duty cycle prediction, the controller drives the pulse width modulation circuit (PWM circuit) to adjust the duty cycle of the switching transistor to the maximum through the first control signal. Essentially, this maximizes the energy transfer efficiency per unit time, driving the output voltage to quickly climb from the "small duty cycle detection stage" and shortening the startup time. At the same time, because the load characteristics and steady-state parameters have been accurately grasped in the early stage, the output at the maximum duty cycle will not exceed the load safety threshold. This not only achieves the core requirement of "fast startup" but also lays the foundation for subsequent switching to the target duty cycle and stable output.

[0052] Step S240: Monitor the real-time output voltage of the soft-start preprocessing circuit through the voltage sampling circuit.

[0053] Step S250: The real-time output voltage is monitored to increase to the target voltage.

[0054] Understandably, by continuously monitoring the dynamic output voltage through the voltage sampling circuit, the controller is provided with real-time feedback data to ensure that the voltage ramp-up progress can be grasped in a timely manner. When the real-time output voltage reaches the preset target voltage, it means that the rapid ramp-up phase is completed, providing an accurate basis for subsequent switching to the target duty cycle and entering steady-state operation. This not only avoids voltage overshoot from damaging the load, but also ensures a smooth transition from acceleration to stability during soft start.

[0055] Step S260: Send a second control signal to the pulse width modulation circuit. The second control signal is used to adjust the duty cycle of the switching transistor from the maximum duty cycle to the target duty cycle, so as to realize the fast soft start of the switching power supply and reach a steady state.

[0056] Once the real-time output voltage reaches the target voltage, the controller drives the pulse width modulation (PWM) circuit via a second control signal to precisely switch the duty cycle of the switching transistor from the "maximum duty cycle used for acceleration" to the previously calculated target duty cycle. The core logic utilizes the adaptability of the target duty cycle to the load and circuit characteristics to keep the output voltage stably maintained at the target value. This terminates the rapid rise phase and avoids voltage overshoot or fluctuations, ultimately achieving a smooth transition of the switching power supply from startup to steady state, thus achieving the core objectives of rapid startup and stable output.

[0057] In one possible embodiment, after sending the second control signal to the pulse width modulation circuit, the method further includes: obtaining the target current output by the soft-start preprocessing circuit in steady state based on the ratio of the target voltage to the load resistance of the resistive load; monitoring the real-time output current of the soft-start preprocessing circuit through the current sampling circuit; correcting the target duty cycle using a PID algorithm based on the current difference between the real-time output current and the target current, and the voltage difference between the real-time output voltage and the target voltage, thereby generating a fourth control signal; and sending the fourth control signal to the pulse width modulation circuit, wherein the fourth control signal is used to adjust the current target duty cycle of the switching transistor so that the output of the soft-start preprocessing circuit is close to the target voltage and the target current, thereby achieving a steady state.

[0058] Among them, the PID algorithm (Proportional, Integral, and Derivative control algorithm) is a classic closed-loop control algorithm. Its core is to dynamically adjust control parameters based on the deviation between the target value and the actual value, through the coordinated calculation of the proportional, integral, and derivative components, to quickly stabilize the system output at the target value: Proportional (P): Directly adjusts the output according to the magnitude of the deviation; the larger the deviation, the larger the adjustment, achieving rapid response; Integral (I): Accumulates historical deviations, eliminating static errors (such as the long-term presence of small deviations), ensuring steady-state stability; Derivative (D): Predicts trends based on the rate of change of the deviation, suppressing overshoot (such as slowing down the system in advance when voltage rises rapidly), improving system stability. Essentially, it is an intelligent adjustment logic that "balances speed, stability, and zero steady-state error," widely used in electronic and industrial scenarios requiring precise closed-loop control.

[0059] Understandably, the core purpose of using the PID algorithm to correct the target duty cycle is to overcome the limitations of open-loop prediction. It can not only compensate for the prediction parameter errors caused by load resistance drift and circuit loss fluctuations, and respond in real time to sudden disturbances such as power grid fluctuations and load changes, but also coordinate and balance the dual target constraints of voltage and current. By eliminating static errors through integration and suppressing overshoot through differentiation, it can ultimately improve steady-state accuracy and anti-interference capability, and ensure that the output is stable and closely matches the target value.

[0060] In one possible embodiment, the step of using a PID algorithm to correct the target duty cycle based on the current difference between the real-time output current and the target current, and the voltage difference between the real-time output voltage and the target voltage, and generating a fourth control signal, includes: detecting that the current difference exceeds a preset current difference range, and / or the voltage difference exceeds a preset voltage difference range; calling the PID algorithm based on the current difference, the voltage difference, and the target duty cycle to calculate the final duty cycle corresponding to the switching transistor when the output of the soft-start preprocessing circuit is the target voltage and the target current; and generating the fourth control signal based on the final duty cycle.

[0061] In this embodiment, adjustment is only initiated when the deviation between the real-time output and the target value exceeds a preset range: specifically, when the current difference (the difference between the real-time current and the target current) exceeds a preset current difference range, and / or the voltage difference (the difference between the real-time voltage and the target voltage) exceeds a preset voltage difference range. The core logic of this "deviation over-limit trigger" design is to avoid ineffective correction of minor fluctuations, reduce the controller's computational load and circuit output oscillations, and ensure that adjustment only intervenes when the output parameters deviate from a safe and stable range, thus balancing steady-state stability with targeted adjustment.

[0062] Furthermore, using the current difference and voltage difference as error feedback bases, and combining them with the previously determined target duty cycle as a reference parameter, a PID algorithm is invoked for coordinated calculation. This ultimately yields a final duty cycle that allows the output to simultaneously match the target voltage and target current, generating a fourth control signal. The key to this process lies in "dual-deviation coordination," which overcomes the limitations of single-parameter correction. Through the comprehensive consideration of voltage and current deviations using the PID algorithm, it ensures that the corrected duty cycle can both compensate for output deviations and maintain the balance of the two parameters, ultimately achieving precise steady-state control of the soft-start preprocessing circuit.

[0063] In one possible embodiment, the soft-start preprocessing circuit includes at least a two-level phase-shifted full-bridge topology; the switching transistors include a first, second, third, and fourth switch located on the primary side of the two-level phase-shifted full-bridge topology, wherein the first and second switches are connected in series, the third and fourth switches are connected in series, and the first, second, third, and fourth switches are connected in parallel; the resistive load is located on the secondary side of the two-level phase-shifted full-bridge topology; and the voltage sampling circuit is connected to the output of the two-level phase-shifted full-bridge topology.

[0064] In specific embodiments, the internal soft-start preprocessing circuit of the switching power supply of this application includes, but is not limited to, two-level phase-shifted full-bridge topology, Buck buck topology, half-bridge topology, Boost-Buck buck-boost topology, flyback topology, forward topology, and LLC resonant topology. Specifically, it can be flexibly selected according to the power level of the switching power supply (e.g., flyback topology is suitable for low-power scenarios, and two-level phase-shifted full-bridge or LLC resonant topology is preferred for medium and high-power scenarios), input and output voltage requirements (e.g., Buck topology is selected for buck requirements, and Boost-Buck topology is selected for buck-boost requirements), and whether electrical isolation is required (e.g., half-bridge, full-bridge, or flyback topology is selected if isolation is required, and Buck topology is selected if isolation is not required). This application does not limit the specific type of topology. As long as the topology circuit can realize the soft-start preprocessing function through duty cycle adjustment and is compatible with the previous parameter calculation, voltage and current monitoring, and steady-state control logic, it does not deviate from the core concept and protection scope of this application.

[0065] As can be seen, in this embodiment, by estimating the load resistance of the current internal circuit of the switching power supply, the final steady-state operating parameters of the circuit are predicted in advance; then the duty cycle is directly set to the maximum duty cycle, driving the voltage and current to rise rapidly; once the circuit output voltage reaches the predicted steady-state operating voltage, the duty cycle is immediately switched to the predicted steady-state duty cycle, at which point loop control is performed, and the circuit converges quickly through PID adjustment, ultimately stabilizing the circuit output in the target operating range, that is, stabilizing near the final steady-state operating parameters, thereby significantly shortening the soft-start time of the switching power supply.

[0066] Please see Figure 3 , Figure 3 This is a circuit diagram of a two-level phase-shifted full-bridge topology circuit provided in an embodiment of this application, as shown below. Figure 3As shown, the two-level phase-shifted full-bridge topology includes a primary side and a secondary side. On the primary side, VPFC is the input DC voltage (output by the PFC circuit). Q1-Q4 are four sets of primary-side switches (each a parallel diode, forming the bridge arm of the phase-shifted full-bridge). Lr and Cr are resonant elements (adapting to the soft-switching characteristics of the two-level topology). RX1 and CX1 form a spike absorption circuit (suppressing switching losses). DD1 and DD2 are primary-side freewheeling diodes. Tr is a transformer (achieving electrical isolation and voltage transformation). Point A is the midpoint of the first bridge arm (the bridge arm formed by Q1 and Q2 in series), and point B is the midpoint of the second bridge arm (the bridge arm formed by Q3 and Q4 in series). These two points are the voltage output nodes of the primary-side bridge arms. The phase-shifted full-bridge generates a voltage signal with a phase difference between points A and B by controlling the conduction sequence of Q1-Q4 (phase-shift control). This signal is transmitted to the primary side of the transformer Tr through the resonant elements Lr and Cr, making it one of the core nodes for realizing primary-side energy transfer and the soft-switching characteristics of the topology. Additionally, D1-D4 on the secondary side are full-bridge rectifier diodes, Lf and Cf form the output filter circuit, and RL is a resistive load.

[0067] Based on the fast soft-start control scheme for the switching power supply provided in this application, the application process in this two-level phase-shifted full-bridge topology is as follows: First, a third control signal (adjusted to a small duty cycle) is sent to the PWM circuits (pulse width modulation circuits) corresponding to Q1-Q4. The reference voltage / current is obtained and the resistance value of RL is calculated using the voltage sampling circuit connected to the RL terminal and the current sampling circuit that measures the output current. Then, the target voltage is determined based on RL and the preset standard voltage / current (current is prioritized if RL is a heating load). Subsequently, the target duty cycle of Q1-Q4 is calculated by combining the VPFC input voltage, the turns ratio (topology gain coefficient) of Tr, and the circuit efficiency. Next, a first control signal is sent to adjust the duty cycle of Q1-Q4 to the maximum, driving the output voltage to rise rapidly. After the voltage sampling circuit detects that the voltage has reached the target value, a second control signal is sent to switch to the target duty cycle. If the voltage / current deviation exceeds the limit due to RL resistance drift or grid fluctuations after steady state, the duty cycle of Q1-Q4 can be corrected by the PID algorithm, ultimately realizing fast soft-start and precise steady-state control of the switching power supply under this topology.

[0068] As can be seen, in this embodiment, in a two-level phase-shifted full-bridge topology with isolation and soft-switching characteristics, the load resistance is accurately obtained by probing with a small duty cycle, the target duty cycle is calculated by combining the topology parameters, the voltage is driven to rise rapidly with the maximum duty cycle, the voltage is switched to the target duty cycle by voltage monitoring, and then the deviation is corrected by PID. This not only takes advantage of the topology performance, but also realizes the safe and fast start-up and accurate steady-state control of the switching power supply.

[0069] Please see Figure 4 , Figure 4This is a schematic diagram of the output voltage curve of a switching power supply provided in an embodiment of this application. For example... Figure 4 As shown, the curve has "output voltage" as the vertical axis and "time" as the horizontal axis. At time t0, the controller sends the first control signal to the PWM circuit, adjusting the duty cycle of the switching transistor to the start-up node of maximum duty cycle. At this time, the output voltage starts to rise rapidly from the initial value (close to 0). The setting of "maximum duty cycle" maximizes the energy transfer efficiency per unit time under the premise that "the load safety threshold is known". It avoids the inefficiency of the traditional soft-start "linear and slow increase of duty cycle" and does not cause overvoltage / overload of the load due to an unpredictable large duty cycle.

[0070] The interval from t0 to t1 corresponds to the process of the voltage sampling circuit continuously monitoring the real-time output voltage. During this stage, the curve maintains a stable and rapid upward trend without significant deviation or abnormal fluctuations. t1 is the critical turning point of the curve: at this moment, the output voltage just reaches the target voltage, corresponding to the time node when the voltage is detected as meeting the target and a second control signal is sent to switch to the target duty cycle. After t1, the curve initially shows slight fluctuations near the target voltage, then quickly stabilizes. This detail corresponds to the PID correction stage after steady-state operation: the slight fluctuations originate from the circuit being briefly affected by topological parasitic parameters and minor load fluctuations when the duty cycle switches from "maximum" to "target," resulting in a small output deviation; however, the subsequent rapid stabilization is precisely the manifestation of the PID algorithm. When the voltage (or current) difference exceeds the preset range, the controller invokes the PID algorithm, correcting the switching duty cycle through the coordinated adjustment of "proportional stage for rapid response to deviation, integral stage for eliminating static error, and derivative stage for suppressing oscillation," ultimately maintaining the output voltage stably near the target value.

[0071] As can be seen, in this embodiment, compared with the existing soft-start scheme that gradually increases the duty cycle from 0 to the target value, this application directly sets the duty cycle to the maximum duty cycle, driving the voltage and current to rise rapidly; once the circuit output voltage reaches the predicted steady-state operating voltage, the duty cycle is immediately switched to the predicted steady-state duty cycle, thereby significantly shortening the soft-start time of the switching power supply and enabling the switching power supply to quickly reach a stable operating state after soft start.

[0072] Please see Figure 5 , Figure 5 This is an overall flowchart of a fast soft-start control method for a switching power supply provided in an embodiment of this application. This fast soft-start control method for a switching power supply is applicable to, for example... Figure 1 The switching power supply shown, combined with Figure 1 ,like Figure 5As shown, the method includes the following steps: S501, Start. S502, Set the preset standard voltage and preset standard current, and issue a soft-start power-on command. S503, Send a third control signal to the pulse width modulation circuit to adjust the duty cycle of the switching transistor to a smaller preset reference duty cycle. S504, Acquire the reference voltage and reference current output by the soft-start preprocessing circuit at the preset reference duty cycle. S505, Calculate the load resistance value of the resistive load based on the reference voltage and reference current. S506, Determine the target voltage of the soft-start preprocessing circuit in steady state based on the load resistance value, the preset standard voltage, and the preset standard current. S507, Determine the target duty cycle of the soft-start preprocessing circuit in steady state based on the target voltage and the preset input voltage of the switching power supply. S508, Send a first control signal to the pulse width modulation circuit to adjust the duty cycle of the switching transistor to the maximum duty cycle. S509, Real-time detection of the real-time output voltage of the soft-start preprocessing circuit. S510, Check whether the real-time output voltage increases to the target voltage. If yes, proceed to step S511; otherwise, proceed to step S509. S511: Send a second control signal to the pulse width modulation circuit to adjust the duty cycle of the switching transistor to the target duty cycle. S512: Correct the target duty cycle so that the output voltage of the soft-start preprocessing circuit is close to the target voltage, thereby achieving a steady state.

[0073] As can be seen, in this embodiment, by estimating the load resistance of the current internal circuit of the switching power supply, the final steady-state operating parameters of the circuit are predicted in advance; then the duty cycle is directly set to the maximum duty cycle, driving the voltage and current to rise rapidly; once the circuit output voltage reaches the predicted steady-state operating voltage, the duty cycle is immediately switched to the predicted steady-state duty cycle, at which point loop control is performed, and the circuit converges quickly through PID adjustment, ultimately stabilizing the circuit output in the target operating range, that is, stabilizing near the final steady-state operating parameters, thereby significantly shortening the soft-start time of the switching power supply.

[0074] Please see Figure 6 , Figure 6 This is a functional unit block diagram of a fast soft-start control device 600 for a switching power supply provided in an embodiment of this application. The fast soft-start control device 600 for a switching power supply is applied to, for example... Figure 1 The switching power supply shown, combined with Figure 1 ,like Figure 6 As shown, the fast soft-start control device 600 of the switching power supply includes the following units: The processing unit 610 is used to determine the target voltage output by the soft-start preprocessing circuit in steady state based on the preset standard voltage, the preset standard current and the load resistance value of the resistive load; and to determine the target duty cycle corresponding to the switching transistor of the soft-start preprocessing circuit in steady state based on the target voltage and the preset input voltage of the switching power supply. The transmitting unit 620 is used to send a first control signal to the pulse width modulation circuit, the first control signal being used to adjust the duty cycle of the switching transistor to the maximum duty cycle; The processing unit 610 is further configured to monitor the real-time output voltage of the soft-start preprocessing circuit through the voltage sampling circuit; and to monitor the real-time output voltage increasing to the target voltage. The transmitting unit 620 is further configured to send a second control signal to the pulse width modulation circuit. The second control signal is configured to adjust the duty cycle of the switching transistor from the maximum duty cycle to the target duty cycle, so as to realize the fast soft start of the switching power supply and reach a steady state.

[0075] In one embodiment, determining the target voltage output by the soft-start preprocessing circuit in steady state based on a preset standard voltage, a preset standard current, and the load resistance of the resistive load includes: determining a target preset standard value that should preferentially satisfy the resistive load between the preset standard voltage and the preset standard current; determining that the target preset standard value is either the preset standard voltage or the preset standard current; if the target preset standard value is determined to be the preset standard voltage, then determining the preset standard voltage as the target voltage; and if the target preset standard value is determined to be the preset standard current, then obtaining a reference voltage output by the soft-start preprocessing circuit in steady state based on the product of the preset standard current and the load resistance; and determining the smaller voltage between the reference voltage and the preset standard voltage as the target voltage.

[0076] In one embodiment, determining the target duty cycle of the switching transistor in steady state of the soft-start preprocessing circuit based on the target voltage and the preset input voltage of the switching power supply includes: determining the voltage ratio between the target voltage and the preset input voltage of the switching power supply; obtaining the preset voltage gain coefficient and preset energy transfer efficiency corresponding to the soft-start preprocessing circuit; and obtaining the target duty cycle of the switching transistor in steady state of the soft-start preprocessing circuit based on the product of the voltage ratio, the preset voltage gain coefficient, and the preset energy transfer efficiency.

[0077] In one embodiment, the soft-start preprocessing circuit further includes a current sampling circuit connected to the output terminal of the soft-start preprocessing circuit, and the controller is connected to the current sampling circuit. Before determining the target voltage output by the soft-start preprocessing circuit in steady state based on a preset standard voltage, a preset standard current, and the load resistance value of the resistive load, the method further includes: sending a third control signal to the pulse width modulation circuit, the third control signal being used to adjust the duty cycle of the switching transistor to a preset reference duty cycle; obtaining a reference voltage output by the soft-start preprocessing circuit at the preset reference duty cycle through the voltage sampling circuit; obtaining a reference current output by the soft-start preprocessing circuit at the preset reference duty cycle through the current sampling circuit; and obtaining the load resistance value of the resistive load based on the ratio of the reference voltage and the reference current.

[0078] In one embodiment, after sending the second control signal to the pulse width modulation circuit, the method further includes: obtaining the target current output by the soft-start preprocessing circuit in steady state based on the ratio of the target voltage to the load resistance of the resistive load; monitoring the real-time output current of the soft-start preprocessing circuit through the current sampling circuit; correcting the target duty cycle using a PID algorithm based on the current difference between the real-time output current and the target current, and the voltage difference between the real-time output voltage and the target voltage, thereby generating a fourth control signal; and sending the fourth control signal to the pulse width modulation circuit, wherein the fourth control signal is used to adjust the current target duty cycle of the switching transistor so that the output of the soft-start preprocessing circuit is close to the target voltage and the target current, thereby achieving steady state.

[0079] In one embodiment, the step of using a PID algorithm to correct the target duty cycle based on the current difference between the real-time output current and the target current, and the voltage difference between the real-time output voltage and the target voltage, and generating a fourth control signal includes: detecting that the current difference exceeds a preset current difference range, and / or the voltage difference exceeds a preset voltage difference range; calling the PID algorithm based on the current difference, the voltage difference, and the target duty cycle to calculate the final duty cycle corresponding to the switching transistor when the output of the soft-start preprocessing circuit is the target voltage and the target current; and generating the fourth control signal based on the final duty cycle.

[0080] In one embodiment, the soft-start preprocessing circuit includes at least a two-level phase-shifted full-bridge topology; the switching transistors include a first, second, third, and fourth switching transistor located on the primary side of the two-level phase-shifted full-bridge topology, wherein the first and second switching transistors are connected in series, the third and fourth switching transistors are connected in series, and the first, second, third, and fourth switching transistors are connected in parallel; the resistive load is located on the secondary side of the two-level phase-shifted full-bridge topology; and the voltage sampling circuit is connected to the output terminal of the two-level phase-shifted full-bridge topology.

[0081] It is understood that since the method embodiments and the device embodiments are different presentations of the same technical concept, the content of the method embodiment section in this application should be adapted to the device embodiment section in a synchronous manner, and will not be repeated here.

[0082] As can be seen, in this embodiment, by estimating the load resistance of the current internal circuit of the switching power supply, the final steady-state operating parameters of the circuit are predicted in advance; then the duty cycle is directly set to the maximum duty cycle, driving the voltage and current to rise rapidly; once the circuit output voltage reaches the predicted steady-state operating voltage, the duty cycle is immediately switched to the predicted steady-state duty cycle, at which point loop control is performed, and the circuit converges quickly through PID adjustment, ultimately stabilizing the circuit output in the target operating range, that is, stabilizing near the final steady-state operating parameters, thereby significantly shortening the soft-start time of the switching power supply.

[0083] Please see Figure 7 , Figure 7 This is a structural block diagram of an electronic device provided in an embodiment of this application, such as... Figure 7 As shown, the electronic device 700 may include one or more of the following components: a processor 710 and a memory 720 coupled to the processor 710, wherein the memory 720 may store one or more computer programs, which may be configured to implement the methods described in the above embodiments when executed by one or more processors 710.

[0084] The processor 710 may include one or more processing cores. The processor 710 connects to various parts within the electronic device 700 using various interfaces and lines, and performs various functions and processes data of the electronic device 700 by running or executing instructions, programs, code sets, or instruction sets stored in the memory 720, and by calling data stored in the memory 720. Optionally, the processor 710 may be implemented using at least one hardware form of Digital Signal Processing (DSP), Field-Programmable Gate Array (FPGA), or Programmable Logic Array (PLA). The processor 710 may integrate one or a combination of several of the following: Central Processing Unit (CPU), Graphics Processing Unit (GPU), and modem. The CPU primarily handles the operating system, user interface, and applications; the GPU is responsible for rendering and drawing the displayed content; and the modem handles wireless communication. It is understood that the modem may also not be integrated into the processor 710 and may be implemented separately using a communication chip.

[0085] The memory 720 may include random access memory (RAM) or read-only memory (ROM). The memory 720 can be used to store instructions, programs, code, code sets, or instruction sets. The memory 720 may include a program storage area and a data storage area. The program storage area may store instructions for implementing an operating system, instructions for implementing at least one function (such as touch functionality, sound playback functionality, image playback functionality, etc.), and instructions for implementing the various method embodiments described above. The data storage area may also store data created by the electronic device 700 during use.

[0086] It is understood that the electronic device 700 may include more or fewer structural elements than those shown in the above block diagram, such as a power module, physical buttons, a Wi-Fi module, a speaker, a Bluetooth module, sensors, etc., without limitation.

[0087] Furthermore, embodiments of this application also provide a computer storage medium storing a computer program that can be loaded by a processor and executed as described above for the fast soft-start control method for a switching power supply. The computer-readable storage medium includes, for example, various media capable of storing program code, such as a USB flash drive, a portable hard drive, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

[0088] It should be noted that, for the sake of simplicity, the foregoing method embodiments are all described as a series of actions. However, those skilled in the art should understand that this application is not limited to the described order of actions, as some steps may be performed in other orders or simultaneously according to this application. Furthermore, those skilled in the art should also understand that the embodiments described in the specification are preferred embodiments, and the actions and modules involved are not necessarily essential to this application.

[0089] In the several embodiments provided in this application, it should be understood that the disclosed methods, apparatuses, and systems can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for example, the division of units is merely a logical functional division, and there may be other division methods in actual implementation; for example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the shown or discussed mutual couplings or direct couplings or communication connections may be through some interfaces, indirect couplings or communication connections between devices or units, and may be electrical, mechanical, or other forms. The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, i.e., they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs. In addition, the functional units in the various embodiments of the present invention can be integrated into one processing unit, or each unit may be physically included separately, or two or more units may be integrated into one unit. The integrated units described above can be implemented in hardware or in the form of hardware plus software functional units.

[0090] The integrated units implemented as software functional units described above can be stored in a computer-readable storage medium. These software functional units, stored in a storage medium, include several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute some steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes: a USB flash drive, a portable hard drive, a magnetic disk, an optical disk, volatile memory, or non-volatile memory. The non-volatile memory can be read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), or flash memory. The volatile memory can be random access memory (RAM), which is used as an external cache. By way of example, but not limitation, many forms of random access memory (RAM) are available, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous linked DRAM (SLDRAM), and direct rambus RAM (DRRAM), etc., which are various media capable of storing program code.

[0091] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0092] The embodiments of this application have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

[0093] While this application discloses the above information, it is not limited thereto. Any person skilled in the art can easily conceive of variations or substitutions without departing from the spirit and scope of this application, and can make various alterations and modifications, including combinations of the different functions and implementation steps described above, as well as software and hardware implementation methods, all of which are within the protection scope of this application.

Claims

1. A fast soft-start control method for a switching power supply, characterized in that, A controller applied to a switching power supply, the switching power supply comprising a soft-start preprocessing circuit, the soft-start preprocessing circuit comprising a resistive load, a switch tube, a voltage sampling circuit and a pulse width modulation circuit, the pulse width modulation circuit being connected with the switch tube and used for adjusting a duty cycle of the switch tube, the voltage sampling circuit being connected with an output end of the soft-start preprocessing circuit, the controller being connected with the voltage sampling circuit and the pulse width modulation circuit respectively; the method comprises: determining a target voltage output by the soft-start preprocessing circuit in a steady state according to a preset standard voltage, a preset standard current and a load resistance of the resistive load; determining a target duty cycle corresponding to the switch tube of the soft-start preprocessing circuit in the steady state according to the target voltage and a preset input voltage of the switching power supply; sending a first control signal to the pulse width modulation circuit, the first control signal being used for adjusting the duty cycle of the switch tube to a maximum duty cycle; monitoring a real-time output voltage of the soft-start preprocessing circuit through the voltage sampling circuit; monitoring that the real-time output voltage increases to the target voltage; sending a second control signal to the pulse width modulation circuit, the second control signal being used for adjusting the duty cycle of the switch tube from the maximum duty cycle to the target duty cycle, so as to realize fast soft-start of the switching power supply and reach the steady state.

2. The method of claim 1, wherein, The method further comprises: determining a target preset standard value of the preset standard voltage and the preset standard current which needs to be satisfied preferentially by the resistive load; judging whether the target preset standard value is the preset standard voltage or the preset standard current; if it is judged that the target preset standard value is the preset standard voltage, determining the preset standard voltage as the target voltage; and if it is judged that the target preset standard value is the preset standard current, obtaining a reference voltage output by the soft-start preprocessing circuit in the steady state according to a product of the preset standard current and the load resistance; and determining the smaller voltage between the reference voltage and the preset standard voltage as the target voltage.

3. The method of claim 2, wherein, The method further comprises: determining a voltage ratio of the target voltage and the preset input voltage of the switching power supply; obtaining a preset voltage gain coefficient and a preset energy transmission efficiency corresponding to the soft-start preprocessing circuit; obtaining the target duty cycle corresponding to the switch tube of the soft-start preprocessing circuit in the steady state according to a product of the voltage ratio, the preset voltage gain coefficient and the preset energy transmission efficiency.

4. The method according to any one of claims 1 to 3, characterized in that, The soft-start preprocessing circuit further comprises a current sampling circuit, the current sampling circuit being connected with the output end of the soft-start preprocessing circuit, the controller being connected with the current sampling circuit. Before the determining the target voltage outputted by the soft-start preprocessing circuit in the steady state according to the preset standard voltage, the preset standard current and the load resistance of the resistive load, the method further comprises: sending a third control signal to the pulse width modulation circuit, the third control signal being used for adjusting the duty cycle of the switch tube to a preset reference duty cycle; acquiring a reference voltage outputted by the soft-start preprocessing circuit under the preset reference duty cycle through the voltage sampling circuit; acquiring a reference current outputted by the soft-start preprocessing circuit under the preset reference duty cycle through the current sampling circuit; obtaining the load resistance of the resistive load according to the ratio of the reference voltage and the reference current.

5. The method of claim 4, wherein, After the sending the second control signal to the pulse width modulation circuit, the method further comprises: obtaining a target current outputted by the soft-start preprocessing circuit in the steady state according to the ratio of the target voltage and the load resistance of the resistive load; monitoring a real-time output current of the soft-start preprocessing circuit through the current sampling circuit; correcting the target duty cycle by using a PID algorithm according to the current difference between the real-time output current and the target current, the voltage difference between the real-time output voltage and the target voltage, and generating a fourth control signal; sending the fourth control signal to the pulse width modulation circuit, the fourth control signal being used for adjusting the target duty cycle of the switch tube at present, so that the output of the soft-start preprocessing circuit approaches the target voltage and the target current, and then reaches the steady state.

6. The method of claim 5, wherein, The correcting the target duty cycle by using the PID algorithm according to the current difference between the real-time output current and the target current, the voltage difference between the real-time output voltage and the target voltage, and generating the fourth control signal, comprises: detecting that the current difference exceeds a preset current difference interval, and / or the voltage difference exceeds a preset voltage difference interval; calling the PID algorithm according to the current difference, the voltage difference and the target duty cycle, calculating a final duty cycle of the switch tube corresponding to the output of the soft-start preprocessing circuit being the target voltage and the target current; generating the fourth control signal according to the final duty cycle.

7. The method of claim 1, wherein, The soft-start preprocessing circuit comprises at least two level-shifted full-bridge topology circuits; The switch tube comprises a first switch tube, a second switch tube, a third switch tube and a fourth switch tube located in a primary circuit of the two level-shifted full-bridge topology circuits, the first switch tube and the second switch tube being connected in series, the third switch tube and the fourth switch tube being connected in series, the first switch tube, the second switch tube, the third switch tube and the fourth switch tube being connected in parallel; The resistive load is located in a secondary circuit of the two level-shifted full-bridge topology circuits; The voltage sampling circuit is connected with an output end of the two level-shifted full-bridge topology circuits.

8. A fast soft-start control device for a switching power supply, characterized in that, The application relates to a controller applied to a switching power supply, wherein the switching power supply comprises a soft-start preprocessing circuit, the soft-start preprocessing circuit comprises a resistive load, a switch tube, a voltage sampling circuit and a pulse width modulation circuit, the pulse width modulation circuit is connected with the switch tube and is used for adjusting the duty cycle of the switch tube, the voltage sampling circuit is connected with the output end of the soft-start preprocessing circuit, the controller is connected with the voltage sampling circuit and the pulse width modulation circuit respectively, and the device comprises: a processing unit which is used for determining a target voltage output by the soft-start preprocessing circuit in a steady state according to a preset standard voltage, a preset standard current and the load resistance of the resistive load, determining a target duty cycle corresponding to the switch tube of the soft-start preprocessing circuit in the steady state according to the target voltage and a preset input voltage of the switching power supply; a sending unit which is used for sending a first control signal to the pulse width modulation circuit, and the first control signal is used for adjusting the duty cycle of the switch tube to a maximum duty cycle; the processing unit is further used for monitoring a real-time output voltage of the soft-start preprocessing circuit through the voltage sampling circuit, and monitoring that the real-time output voltage increases to the target voltage; the sending unit is further used for sending a second control signal to the pulse width modulation circuit, and the second control signal is used for adjusting the duty cycle of the switch tube from the maximum duty cycle to the target duty cycle, so that the switching power supply is rapidly soft-started and reaches the steady state.

9. An electronic device, comprising: The computer program / instruction is executed by the processor to realize the steps of the method in any one of claims 1-7.

10. A computer readable storage medium having stored thereon computer programs / instructions, characterized in that, The computer program / instruction is executed by the processor to realize the steps of the method in any one of claims 1-7.

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