Soft start control circuit and method, resonant transformation control circuit and electronic equipment

Abstract

The invention discloses a soft start control circuit and method, a resonant transformation control circuit and electronic equipment, and the soft start control circuit comprises a charge feedback circuit which obtains a charge feedback signal through employing a resonant output signal; the voltage feedback circuit is used for obtaining a voltage feedback signal by utilizing a difference value between the power supply output signal and the target reference voltage; the logic control circuit is used for generating a first control signal in a first starting stage; in a second starting stage, generating a second control signal by adopting the maximum preset switching frequency and the adjustable dead time; in a third start-up stage, slope compensation is performed on the voltage feedback signal to obtain a feedback adjustment signal, and a third control signal is generated by using the feedback adjustment signal and the charge feedback signal; the logic control circuit adjusts the inverter AC signal by using the first to third control signals. By means of the mode, the soft start control circuit is high in dynamic response speed, small in starting current and simple in control logic.

Description

Technical Field

[0001] The present application relates to the field of power supply technology, and in particular to a soft start control circuit and method, a resonant conversion control circuit, and an electronic device. Background Art

[0002] Nowadays, resonant converters are widely used in the field of high-frequency switching power supplies because of their unique switching characteristics, which can achieve low switching losses, high conversion efficiency and high power density. LLC resonant converters contain an additional inductance (L) in series with two other components, inductor L and capacitor (C), hence the name LLC converter. As a more classic topology in resonant converters, its control method generally adopts single voltage loop control, that is, direct frequency control method, or average current control method. The common problems of these two methods are low system bandwidth, poor dynamic response, and large output ripple.

[0003] Based on this, the new generation of LLC resonant converters adopts a charge control mode, which samples the charge information of the resonant cavity as the inner loop control variable. However, because the charge mode controls the LLC switching frequency indirectly, compared with the direct frequency control mode, the frequency of each cycle of the charge-controlled LLC is unknown. Therefore, its soft-start strategy is more complicated than direct frequency control, and there are still problems such as large starting current and poor output voltage linearity. Summary of the invention

[0004] The main technical problem solved by the present application is to provide a soft start control circuit and method, a resonant conversion control circuit, and an electronic device, which can solve the problems of poor dynamic response, large output ripple, large starting current, and poor output voltage linearity in the control method of the LLC resonant converter in the prior art.

[0005] In order to solve the above technical problems, a technical solution adopted by the present application is: to provide a soft start control circuit, which is applied to the start-up control of a resonant conversion circuit, wherein the resonant conversion circuit includes an inverter circuit, a resonant circuit and an electric energy conversion circuit, the resonant circuit is coupled to the inverter circuit and the electric energy conversion circuit, and the electric energy conversion circuit is used to couple with a load circuit, wherein the soft start control circuit includes: a charge feedback circuit, which is used to couple with the resonant circuit to obtain a resonant output signal in the resonant circuit, so as to obtain a charge feedback signal by using the resonant output signal; a voltage feedback circuit, which is used to couple with the electric energy conversion circuit to obtain a power output signal output by the electric energy conversion circuit to the load circuit, so as to obtain a voltage feedback signal by using the difference between the power output signal and a target reference voltage; a logic control circuit, which is coupled to the charge feedback circuit and the voltage feedback circuit, and is used to couple with the inverter circuit The logic control circuit is configured as follows: in a first startup phase, a first control signal is generated by a preset rule; in a second startup phase, a charge feedback signal sent by a charge feedback circuit and a voltage feedback signal sent by a voltage feedback circuit are received, and a second control signal is generated by using a maximum preset switching frequency and an adjustable dead time; wherein the adjustable dead time is positively correlated with the difference; in a third startup phase, a slope compensation is performed on the voltage feedback signal by using a preset slope compensation slope to obtain a feedback adjustment signal, so as to generate a third control signal by using the feedback adjustment signal and the charge feedback signal; the logic control circuit is also used to sequentially send the first control signal, the second control signal and the third control signal to the inverter circuit, so that the inverter circuit sequentially uses the first control signal, the second control signal and the third control signal to adjust the inverter AC signal output to the resonant circuit.

[0006] Among them, the logic control circuit is configured as follows: after the power-on set time, entering the second startup stage from the first startup stage; when the power output signal or the voltage feedback signal is greater than or equal to the product between the average value of the charge feedback signal and the mode switching control coefficient, entering the third startup stage from the second startup stage.

[0007] Among them, the charge feedback circuit includes a current sampling subcircuit, an integration subcircuit and a voltage bias subcircuit, the current sampling subcircuit is coupled to the resonant circuit and the integration subcircuit, and the integration subcircuit and the voltage bias subcircuit are coupled to the logic control circuit; wherein the current sampling subcircuit is used to sample and obtain the resonant current signal in the resonant output signal; the integration subcircuit is used to receive the resonant current signal sent by the current sampling subcircuit, so as to integrate and adjust the resonant current signal into a phase-modulated voltage signal; the logic control circuit is used to receive the phase-modulated voltage signal sent by the integration subcircuit and the preset bias voltage output by the voltage bias subcircuit, so as to superimpose the preset bias voltage on the phase-modulated voltage signal to obtain a charge feedback signal.

[0008] The preset bias voltage is greater than or equal to half of the difference between the peak and the valley of the phase modulation voltage signal.

[0009] Among them, the charge feedback circuit includes a voltage sampling sub-circuit, which is coupled to the resonant circuit and the logic control circuit to sample and obtain the resonant capacitor voltage in the resonant circuit; the logic control circuit is used to receive the resonant capacitor voltage sent by the voltage sampling sub-circuit to obtain a charge feedback signal using the resonant capacitor voltage.

[0010] The inverter circuit includes a first switch subcircuit and a second switch subcircuit, the first switch subcircuit is coupled to the second switch subcircuit, the resonant circuit and the logic control circuit, and the second switch subcircuit is coupled to the logic control circuit; wherein the third control signal includes a first drive signal and a second drive signal, and the logic control circuit is configured as follows: in the third startup stage, in the first half cycle of each signal cycle of the third control signal, when the second drive signal is adjusted from the first level to the second level, a delay setting time length or a preset slope compensation slope is used to perform slope compensation on the voltage feedback signal to obtain a feedback adjustment signal; and the delay setting time length adjusts the first drive signal from the second level to the first level; when the voltage amplitude of the feedback adjustment signal is equal to that of the charge feedback signal, the first drive signal is adjusted from the first level to the second level; in the second half cycle of each signal cycle, the first drive signal of each first half cycle is copied to obtain the second drive signal; the logic control circuit is also used to send the first drive signal and the second drive signal to the first switch subcircuit and the second switch subcircuit respectively, so that the first switch subcircuit and the second switch subcircuit change the switch state under the action of the first drive signal and the second drive signal respectively, so as to adjust the inverter AC signal.

[0011] The adjustable dead time is the product of the difference and the dead time adjustment coefficient plus the sum of the preset minimum dead time.

[0012] To solve the above technical problems, another technical solution adopted in the present application is: to provide a soft start control method, which is applied to the start-up control of a resonant conversion circuit, and the soft start control method includes: obtaining a resonant output signal and a power supply output signal; obtaining a charge feedback signal using the resonant output signal; obtaining a voltage feedback signal using the power supply output signal; generating a first control signal using a preset rule; adjusting the inverter AC signal using the first control signal; after the power-on set time, detecting whether the power supply output signal or the voltage feedback signal is less than the product between the average value of the charge feedback signal and the mode switching control coefficient; if the power supply output signal or the voltage feedback signal is less than the product, generating a second control signal using a maximum preset switching frequency and an adjustable dead time; wherein the adjustable dead time is positively correlated with the voltage feedback signal; adjusting the inverter AC signal using the second control signal; if the power supply output signal or the voltage feedback signal is greater than or equal to the product, performing slope compensation on the voltage feedback signal using a preset slope compensation slope to obtain a feedback adjustment signal; generating a third control signal using the feedback adjustment signal and the charge feedback signal; and adjusting the inverter AC signal using the third control signal.

[0013] Among them, the step of using the resonant output signal to obtain the charge feedback signal includes: obtaining the resonant current signal in the resonant output signal; integrating and adjusting the resonant output signal into a phase-modulated voltage signal; and superimposing a preset bias voltage on the phase-modulated voltage signal to obtain the charge feedback signal.

[0014] The step of obtaining the charge feedback signal by using the resonant output signal includes: obtaining the resonant capacitor voltage in the resonant output signal; and obtaining the charge feedback signal by using the resonant capacitor voltage.

[0015] Among them, the third control signal includes a first drive signal and a second drive signal, and the step of using a preset slope compensation slope to perform slope compensation on the voltage feedback signal to obtain a feedback adjustment signal includes: in the first half period of each signal cycle of the third control signal, when the second drive signal is adjusted from the first level to the second level, delaying the setting time length or simultaneously using the preset slope compensation slope to perform slope compensation on the voltage feedback signal to obtain the feedback adjustment signal; the step of using the feedback adjustment signal and the charge feedback signal to generate the third control signal includes: delaying the setting time length to adjust the first drive signal from the second level to the first level; when the voltage amplitude of the feedback adjustment signal is equal to that of the charge feedback signal, adjusting the first drive signal from the first level to the second level; in the second half period of each signal cycle, copying the first drive signal of each first half period to obtain the second drive signal; the step of using the third control signal to adjust the inverter AC signal includes: using the first drive signal and the second drive signal to adjust the inverter AC signal.

[0016] In order to solve the above technical problems, another technical solution adopted in the present application is: to provide a resonant conversion control circuit, wherein the resonant conversion control circuit includes a resonant conversion circuit and a soft start control circuit, the resonant conversion circuit includes an inverter circuit, a resonant circuit and an electric energy conversion circuit, the resonant circuit couples the inverter circuit and the electric energy conversion circuit, the electric energy conversion circuit is used to couple with a load circuit, and the soft start control circuit couples the inverter circuit, the resonant circuit and the electric energy conversion circuit; wherein the soft start control circuit is a soft start control circuit as described in any of the above items.

[0017] To solve the above technical problems, another technical solution adopted in the present application is: to provide an electronic device, wherein the electronic device includes a shell and a power supply circuit connected to the shell; wherein the power supply circuit is a soft start control circuit as described in any of the above items, or a resonant conversion control circuit as described above.

[0018] The beneficial effects of the present application are as follows: Different from the prior art, the charge feedback circuit in the soft start control circuit provided by the present application is used to obtain the resonant output signal in the resonant circuit, so as to obtain the charge feedback signal by using the resonant output signal; the voltage feedback circuit obtains the power output signal output by the power conversion circuit to the load circuit, so as to obtain the voltage feedback signal by using the difference between the power output signal and the target reference voltage; the logic control circuit is configured as follows: in the first startup stage, a first control signal is generated by using a preset rule; in the second startup stage, a charge feedback signal sent by the charge feedback circuit and a voltage feedback signal sent by the voltage feedback circuit are received, and a second control signal is generated by using a maximum preset switching frequency and an adjustable dead time; wherein the adjustable dead time is positively correlated with the difference; in the third startup stage, a preset slope compensation slope is used to perform slope compensation on the voltage feedback signal to obtain a feedback adjustment signal, so as to generate a third control signal by using the feedback adjustment signal and the charge feedback signal; the logic control circuit is also used to sequentially convert the first control signal, the second control signal and the third control signal into a second control signal. The control signal is sent to the inverter circuit, so that the inverter circuit sequentially adjusts the inverter AC signal output to the resonant circuit using the first control signal, the second control signal and the third control signal, so that in the initial stage of the soft start control circuit starting operation, that is, the initial stage of power-on startup, different control strategies are adopted in different startup stages to timely suppress the instantaneous impact current to avoid loss to the circuit; by realizing control at the maximum preset switching frequency in the second startup stage, and adjusting the duty cycle in response to the difference between the power supply output signal and the target reference voltage, the dynamic response speed is faster and the startup resonant cavity current is smaller; and in the third startup stage, the control is realized by comparing the output values ​​of the charge feedback loop and the voltage feedback loop, so that the input power can be quickly and accurately controlled according to the output load, and the dynamic response speed of the loop is further improved, the control logic is relatively simple, and better bandwidth and dynamic performance can be achieved, and the resonant cavity current can also be accurately controlled, so that the linearity of the output voltage of the resonant conversion circuit that realizes the control is also better. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative work, among which: Figure 1 It is a structural schematic diagram of the first implementation mode of the soft start control circuit of the present application; Figure 2 yes Figure 1 A waveform diagram of a voltage feedback signal in a voltage feedback circuit according to an embodiment; Figure 3yes Figure 1 A waveform diagram of an embodiment of a charge feedback signal in a charge feedback circuit; Figure 4 yes Figure 1 A schematic diagram of a waveform of a third control signal sent by the soft start control circuit in the third startup phase; Figure 5 It is a structural schematic diagram of a second implementation mode of the soft start control circuit of the present application; Figure 6 It is a structural schematic diagram of a third embodiment of the soft start control circuit of the present application; Figure 7 It is a structural schematic diagram of a fourth embodiment of the soft start control circuit of the present application; Figure 8 It is a flowchart of the first implementation method of the power startup control method of the present application; Fig. 9 yes Figure 8 A schematic diagram of a flow chart of an embodiment of S52; Fig.10 yes Figure 8 A schematic diagram of a flow chart of another embodiment of S52; Fig.11 It is a flow chart of the second implementation mode of the power startup control method of the present application; Fig.12 It is a structural schematic diagram of an implementation scheme of a resonant conversion control circuit of the present application; Fig.13 It is a schematic structural diagram of an embodiment of an electronic device of the present application. DETAILED DESCRIPTION

[0020] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0021] The terms "first", "second" and "third" in this application are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. Thus, the features defined as "first", "second" and "third" may explicitly or implicitly include at least one of the features. In the description of this application, the meaning of "multiple" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined. All directional indications (such as up, down, left, right, front, back...) in the implementation mode of this application are only used to explain the relative position relationship, movement, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication also changes accordingly. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but optionally also includes steps or units that are not listed, or optionally also includes other steps or units inherent to these processes, methods, products or devices.

[0022] Reference to "embodiment" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiment may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0023] The present application is described in detail below with reference to the accompanying drawings and implementation methods.

[0024] See also Figure 1 , Figure 1 1 is a schematic diagram of the structure of the first embodiment of the soft start control circuit of the present application. In this embodiment, the soft start control circuit 10 includes: a charge feedback circuit 11, a voltage feedback circuit 12 and a logic control circuit 13.

[0025] Among them, a soft start control circuit 10 provided in the present application is specifically used for the startup control of the resonant conversion circuit 100, and the resonant conversion circuit 100 is used in the power supply of the power load, using the externally provided power input signal, and adjusting and controlling the power input signal accordingly to obtain the power output signal Vo, and then providing it to the power load in any reasonable electronic device such as a server, a computer, an intelligent communication device, etc. for operation, and this embodiment does not limit this.

[0026] Specifically, the resonant conversion circuit 100 further includes an inverter circuit 101 , a resonant circuit 102 and an electric energy conversion circuit 103 . The resonant circuit 102 is coupled to the inverter circuit 101 and the electric energy conversion circuit 103 . The electric energy conversion circuit 103 is used to couple to the load circuit 201 .

[0027] The inverter circuit 101 is used to receive a power input signal, and utilizes its internal switching action mechanism, such as the opening and closing action mechanism of switching devices such as IGBT (Insulated Gate Bipolar Transistor), high-frequency transistor, MOSFET (Metal Oxide Semiconductor Field Effect Transistor), and triode, to quickly switch direct current or alternating current under signal control to generate an alternating voltage waveform and obtain an inverter AC signal.

[0028] It is worth noting that the power input signal can be specifically understood as an external DC power supply, or a power input provided by an AC power supply, and can also be understood as a secondary power supply output after power conversion and adjustment of a municipal power supply, a photovoltaic power supply, an independent generator or any other reasonable superior AC or DC power supply.

[0029] In addition, the term "coupled" herein refers to any direct and indirect connection means. Therefore, if the first circuit is described as being coupled to the second circuit, it means that the first circuit can be directly connected to the second circuit through electrical connection or signal connection methods such as wireless transmission, optical transmission, etc., or can be indirectly connected to the second circuit through other circuits or connection means.

[0030] The resonant circuit 102 is directly connected to the inverter circuit 101 to receive the inverter AC signal sent by the inverter circuit 101, and performs one or more of any reasonable signal adjustments such as filtering, shaping, phase shifting, etc. on the inverter AC signal to obtain a resonant output signal, so as to achieve better output characteristics and ensure that subsequent links, such as the power conversion circuit 103 or the load, obtain more stable and efficient power.

[0031] The power conversion circuit 103 is coupled to the resonant circuit 102 to receive the resonant output signal sent by the resonant circuit 102, and performs power conversion and regulation control on the resonant output signal to obtain a stable power output, that is, a power output signal Vo, which is then output to the load circuit 201 to meet the power usage of the load circuit 201.

[0032] The load circuit 201 can be understood as a signal function circuit that operates using the power output signal Vo of the power conversion circuit 103 .

[0033] Specifically, the charge feedback circuit 11 is used to couple with the resonant circuit 102, and is used to sample and obtain the resonant output signal from the resonant circuit 102, so as to perform one or more of any reasonable signal processing such as voltage regulation, filtering, integral transformation, phase modulation and voltage biasing based on the resonant output signal, so as to obtain a charge feedback signal Vcr that can reflect the current charge information of the resonant circuit 102 in real time.

[0034] The voltage feedback circuit 12 is used to couple with the power conversion circuit 103, and is used to sample and obtain the power output signal Vo output to the load circuit 201 from the power conversion circuit 103, so as to make a difference between the currently obtained power output signal Vo and the target reference voltage Vref to obtain the difference Verr between the two, and then adopt a voltage loop or speed loop control strategy or a PI (proportional integral) controller based on the difference Verr to obtain a specific output signal for realizing signal regulation, namely, a voltage feedback signal Vc.

[0035] It is worth noting that the target reference voltage Vref can be specifically understood as a reference voltage that varies during the entire startup phase, in which the power output signal Vo increases monotonically and linearly from 0 to the target output voltage Vobj in a theoretical state and stabilizes at the target output voltage Vobj.

[0036] The logic control circuit 13 is coupled to the charge feedback circuit 11 and the voltage feedback circuit 12 , and is used to be coupled to the inverter circuit 101 .

[0037] The logic control circuit 13 is configured to generate a first control signal in a first startup phase based on a preset program and a preset rule.

[0038] Please continue reading Figure 2 , Figure 2 yes Figure 1 A waveform diagram of a voltage feedback signal in a voltage feedback circuit according to an embodiment of the present invention.

[0039] It is worth noting that the first startup stage and the second startup stage and the third startup stage mentioned in this article can be specifically understood as the soft start control circuit 10 starting from power on, or obtaining the resonant output signal in the resonant circuit 102, or obtaining the power output signal Vo output by the power conversion circuit 103 to the load circuit 201, to start working, until the power output signal Vo output by the power conversion circuit 103 to the load circuit 201 stabilizes at the target output voltage Vobj, or the voltage feedback signal Vc stabilizes at the preset adjustment control value in the initial stage, and based on the set rules, the initial stage is further divided into different startup stages in time sequence.

[0040] For the convenience of quantification, the duration of the soft start control circuit 10 powering on the starter can be specifically divided into time intervals, and / or the entire process of the power output signal Vo output by the power conversion circuit 103 to the load circuit 201 rising from 0V (volts) to the target output voltage Vobj and stabilizing at the target output voltage Vobj; and / or, the duration of the voltage feedback signal Vc rising from 0V to a preset adjustment control value can be divided into time intervals to obtain the first start-up stage, the second start-up stage, and the third start-up stage.

[0041] In some embodiments, the first startup stage can be specifically determined according to the set duration, that is, the soft start control circuit 10 is powered on as the starting moment, and the time period T0-T1 of the set running duration is the first startup stage. It can also be determined according to the T0-T1 time period corresponding to the output voltage of the power supply output signal Vo rising from 0V to the preset voltage value. The present application does not limit this.

[0042] Among them, in the initial stage when the resonant conversion circuit 100 receives the power input signal input, it is usually necessary to charge the bootstrap capacitor of the high-side switch tube of the inverter circuit 101, and the charging time needs to ensure that the bootstrap voltage is sufficient. Therefore, the set duration can be specifically determined by the soft start control circuit 10 to ensure that the bootstrap voltage is sufficient and leave a reasonable margin. This application does not limit this.

[0043] In addition, the preset rule can be to use a preset duty cycle, a preset signal frequency, or a preset number of continuous pulses, and stop sending pulses at other times, and other arbitrary rules to generate the first control signal. It is specifically set and adjusted by the actual control scenario of the soft start control circuit 10 to ensure that the bootstrap voltage is sufficient, and this application does not limit this.

[0044] Furthermore, in the second startup stage, the logic control circuit 13 is also used to receive the charge feedback signal Vcr sent by the charge feedback circuit 11 and the voltage feedback signal Vc sent by the voltage feedback circuit 12, so as to generate a second control signal corresponding to the maximum preset switching frequency fmax and the adjustable dead time Td of the resonant circuit 102.

[0045] In addition, the dead time refers to the time introduced to prevent the two switch tubes of the push-pull connection from being turned on at the same time, and the interlock delay time set to prevent the bridge arm from being directly turned on, to ensure that the switch tube is turned on again after being turned off, to avoid short-circuit problems caused by asymmetric turn-on and turn-off times.

[0046] In some embodiments, the adjustable dead time Td is positively correlated with the difference Verr between the power output signal Vo and the target reference voltage Vref, that is, when the difference Verr increases, the adjustable dead time Td also increases accordingly, so that the duty cycle of the second control signal decreases accordingly, so that a larger resonant output signal appears in the initial stage of startup, and the corresponding power output signal Vo is also larger. When the difference Verr with the target reference voltage Vref is large, the resonant output signal can be reduced as quickly as possible to effectively achieve soft start.

[0047] Please continue reading Figure 3 and Figure 4 ,in, Figure 3 yes Figure 1 A waveform diagram of an embodiment of a charge feedback signal in a charge feedback circuit, Figure 4 yes Figure 1 Schematic diagram of the waveform of the third control signal sent by the soft start control circuit in the third startup stage.

[0048] Specifically, in the third startup stage, the logic control circuit 13 performs slope compensation on the voltage feedback signal Vc by using a preset slope compensation slope to obtain a feedback adjustment signal Vcomp, and then compares the feedback adjustment signal Vcomp with the charge feedback signal Vcr to generate a third control signal of the charge feedback signal Vcr based on the difference between the two.

[0049] It is worth noting that the slope compensation is a control technology used to improve the stability of the system and reduce steady-state errors. By superimposing a slope-controllable ramp signal on the set voltage signal, the dynamic response characteristics of the system can be changed. Among them, the preset slope compensation slope refers to the slope parameter used for slope compensation. This slope can be adjusted according to the needs of the system to achieve the optimal compensation effect.

[0050] Furthermore, the logic control circuit 13 is also used to send the first control signal, the second control signal and the third control signal to the inverter circuit 101 in sequence, so that the inverter circuit 101 changes the switching state under the action of the first control signal, the second control signal and the third control signal in sequence, thereby adjusting the operation of the resonant circuit 102, so as to adjust the inverter AC signal output by the inverter circuit 101 to the resonant circuit 102, thereby suppressing the instantaneous large current in the initial stage as much as possible.

[0051] In some embodiments, the first control signal, the second control signal and the third control signal can specifically be one or more of any reasonable control signals such as PWM (Pulse Width Modulation) signals or PFM (Pulse Frequency Modulation) signals, and the present application does not limit this.

[0052] In some embodiments, the logic control circuit 13 may specifically include a control chip, an MCU (MicroController Unit) circuit, a CPU (Central Processing Unit), a single-chip microcomputer, a field programmable gate array, a programmable logic device, a discrete gate or transistor logic device, discrete hardware, or any other reasonable circuit unit with a signal processing function, and the present application does not limit this.

[0053] The above scheme adopts different control strategies in different startup stages to timely suppress instantaneous impact current in the initial stage of the soft start control circuit 10 starting operation, that is, the initial stage of power-on startup, so as to avoid loss to the circuit; realizes control at the maximum preset switching frequency fmax in the second startup stage, and adjusts the duty cycle in response to the difference Verr between the power output signal Vo and the target reference voltage Vref, so that the dynamic response speed is faster and the startup resonant cavity current is smaller; and in the third startup stage, control is realized by comparing the output values ​​of the charge feedback loop and the voltage feedback loop, which can quickly and accurately control the input power according to the output load, and further improve the dynamic response speed of the loop, the control logic is relatively simple, and can achieve better bandwidth and dynamic performance, and can also accurately control the resonant cavity current, so that the linearity of the output voltage of the controlled resonant conversion circuit 100 is also better.

[0054] In one embodiment, the logic control circuit 13 is specifically configured as follows: after the power-on setting time, that is, according to the time setting, it enters the second startup stage from the first startup stage, so as to change from adopting the control strategy corresponding to the first startup stage to adopting the control strategy corresponding to the second startup stage to implement corresponding startup control of the resonant conversion circuit 100, that is, from using the first control signal to adjust the inverter AC signal to using the second control signal.

[0055] Furthermore, the logic control circuit 13 is also used to enter the third startup stage from the second startup stage when it is determined that the current power supply output signal Vo or the voltage feedback signal Vc is greater than or equal to the product of the average value of the charge feedback signal Vcr and the mode switching control coefficient k1, so as to change from adopting the control strategy corresponding to the second startup stage to adopting the control strategy corresponding to the third startup stage to implement corresponding startup control on the resonant conversion circuit 100, that is, from using the second control signal to adjust the inverter AC signal to using the third control signal to adjust the inverter AC signal.

[0056] It is understandable that the first startup stage, the second startup stage and the third startup stage are specifically divided into intervals according to a time sequence, and each time interval is continuous.

[0057] The first startup stage is specifically divided according to the time setting, such as taking the power-on startup as the starting time T0, and taking the working operation setting time T1 as the ending time.

[0058] The termination time T1 of the first startup stage also corresponds to the starting time of the second startup stage. The judgment condition for the termination time of the second startup stage is that the logic control circuit 13 determines whether the current power output signal Vo or the voltage feedback signal Vc is less than the product of the average value of the charge feedback signal Vcr and the mode switching control coefficient k1, and takes the time corresponding to the power output signal Vo or the voltage feedback signal Vc being equal to the product as the termination time T2 of the second startup stage, which is also the starting time of the third startup stage.

[0059] It can be seen that the first startup stage specifically corresponds to the T0-T1 time stage, the second startup stage corresponds to the T1-T2 time stage, and the third startup stage corresponds to the T2 and subsequent time stages.

[0060] It is worth noting that, in the initial stage of the electric start of the resonant conversion circuit 100, the power output signal Vo and the voltage feedback signal Vc have similar monotonic linear increase characteristics and are stable at a certain constant value, but the corresponding monotonic linear increase slopes are different. The mode switching control coefficient k1 corresponding to the comparison of the size corresponding to the power output signal Vo and the product as the judgment condition for the termination of the second start-up stage is different from the mode switching control coefficient k1 corresponding to the comparison of the size corresponding to the voltage feedback signal Vc and the product as the judgment condition for the termination of the second start-up stage. The specific details are determined by the actual control scenario, and the present application does not limit this.

[0061] In one embodiment, in the second startup stage, the logic control circuit 13 uses the maximum preset switching frequency fmax and the adjustable dead time Td to generate the second control signal, and specifically uses the difference Verr between the power output signal Vo and the target reference voltage Vref to adjust the adjustable dead time Td.

[0062] The adjustable dead time Td may specifically be the product of the difference Verr and the dead time adjustment coefficient k2 plus the preset minimum dead time Td-min, that is, the adjustable dead time Td=Td-min+k2*Verr; and the dead time adjustment coefficient k2 is a positive value.

[0063] In other embodiments, the logic control circuit 13 can also specifically use the voltage feedback signal Vc to adjust the adjustable dead time Td, and the adjustable dead time Td is negatively correlated with the voltage feedback signal Vc. Specifically, it can also be the product of the voltage feedback signal Vc and the dead zone control coefficient k3 plus the sum of the preset maximum dead time Td-max, that is, the adjustable dead time Td=Td-max+k3*Vc; at this time, the dead zone control coefficient k3 is a negative value.

[0064] It is worth noting that the preset minimum dead time Td-min and the preset maximum dead time Td-max can specifically be the minimum dead time and maximum dead time obtained by reasonably setting the minimum switching dead time and control requirements according to the physical characteristics of the inverter circuit 101, and are determined by the actual control scenario, and this application does not limit this.

[0065] See also Figure 5 , Figure 5 2 is a schematic diagram of the structure of the second embodiment of the soft start control circuit of the present application. The difference between the soft start control circuit in this embodiment and the first embodiment of the soft start control circuit provided in the present application is that the charge feedback circuit 21 in the soft start control circuit 20 specifically further includes a current sampling subcircuit 211, an integration subcircuit 212 and a voltage bias subcircuit 213.

[0066] Specifically, the current sampling subcircuit 211 is coupled to the resonant circuit 102 and the integrating subcircuit 212 , and the integrating subcircuit 212 and the voltage biasing subcircuit 213 are coupled to the logic control circuit 23 .

[0067] The current sampling subcircuit 211 is used to sample and obtain a resonant current signal in a resonant output signal from the resonant circuit 102 .

[0068] It can be understood that the resonant output signal in the resonant circuit 102 includes a resonant current signal representing the input current and a resonant capacitor voltage representing the input voltage. The current sampling subcircuit 211 can specifically utilize any reasonable circuit unit such as a current transformer and / or a sampling resistor to obtain the resonant current signal, or a current sampling signal that has a specific functional relationship with the resonant current signal. This application does not limit this.

[0069] The integration sub-circuit 212 is used to receive the resonant current signal sent by the current sampling sub-circuit 211 to integrate and adjust the resonant current signal to obtain a phase-modulated voltage signal.

[0070] The integral regulation of the resonant current signal by the integrator circuit 212 may specifically be to make the phase of the phase-modulated voltage signal lag the resonant current signal by 90°.

[0071] It is worth noting that by sampling the resonant current signal of the resonant circuit 102 and then integrating the resonant current signal, the charge information of the resonant circuit 102 is obtained. This charge information can directly represent the input power of a single cycle, and the phase lags behind the resonant current signal by 90°. If the input current is used as feedback information for the subsequent control signal, only the input current is represented, and when the input voltage changes, it cannot respond quickly to the output. Therefore, in order to characterize the input power and improve the dynamic response speed, after obtaining the resonant current signal, the resonant current signal is further integrated and adjusted to obtain a phase-modulated voltage signal.

[0072] Furthermore, the voltage bias subcircuit 213 is used to generate a preset bias voltage Vcm, and the logic control circuit 23 is used to receive the phase modulation voltage signal sent by the integration subcircuit 212 and the preset bias voltage Vcm outputted by the voltage bias subcircuit 213 accordingly, so as to superimpose the preset bias voltage Vcm with the phase modulation voltage signal to obtain a charge feedback signal Vcr.

[0073] It is worth noting that the phase-modulated voltage signal is actually an AC signal that periodically crosses zero. In order to facilitate the generation of subsequent control signals, the AC signal needs to be raised as a whole to avoid the existence of negative current.

[0074] In addition, the preset bias voltage Vcm can ensure the integrity and stability of the charge feedback signal Vcr, avoid interference caused by the integrator circuit 212 at the zero crossing point, and also take into account the comparison threshold of the soft start mode switching.

[0075] Among them, the preset bias voltage Vcm can be understood as a bias voltage that raises the AC signal as a whole, so as to obtain a charge feedback signal Vcr without negative current through signal superposition, which is used to better ensure the integrity and anti-interference ability of the charge feedback signal Vcr, and the average value of the charge feedback signal Vcr is equal to the value of the preset bias voltage Vcm.

[0076] It can be understood that the logic control circuit 23 specifically enters the third startup stage from the second startup stage when it is determined that the current power output signal Vo or the voltage feedback signal Vc is greater than or equal to the product of the average value of the charge feedback signal Vcr and the mode switching control coefficient k1, that is, Vo≥k1*Vcm, or Vcr≥k1*Vcm, so as to change from adopting the control strategy corresponding to the second startup stage to adopting the control strategy corresponding to the third startup stage to implement corresponding startup control for the resonant conversion circuit 100.

[0077] In some embodiments, the preset bias voltage Vcm is greater than or equal to half of the difference Verr between the peak and the valley of the phase modulation voltage signal, so as to effectively prevent the charge feedback signal Vcr from generating a negative current.

[0078] In some embodiments, the preset bias voltage Vcm is greater than or equal to half of the difference Verr between the peak and the trough of the phase modulation voltage signal, and is not greater than 1.5V, which is not limited in the present application.

[0079] It is understandable that, in this embodiment, the voltage feedback circuit 22 and the logic control circuit 23 are respectively the same as the voltage feedback circuit 12 and the logic control circuit 13. For details, please refer to Figure 1-4 And the related text content will not be repeated here.

[0080] See also Figure 6 , Figure 6 1 is a schematic diagram of the structure of the third embodiment of the soft start control circuit of the present application. The difference between the soft start control circuit in this embodiment and the first embodiment of the soft start control circuit provided in the present application is that the inverter circuit 101 in the resonant conversion circuit 100 further includes a first switch sub-circuit 1011 and a second switch sub-circuit 1012.

[0081] Specifically, the first switch sub-circuit 1011 is coupled to the second switch sub-circuit 1012 , the resonant circuit 102 and the logic control circuit 33 , and the second switch sub-circuit 1012 is coupled to the logic control circuit 33 .

[0082] Correspondingly, the third control signal specifically includes a first drive signal Gate_H and a second drive signal Gate_L, wherein: Figure 4As shown, in the third startup stage, the logic control circuit 33 is specifically used to, in the first half cycle of each signal cycle of the second control signal, respond to the starting moment of this stage, that is, the moment when the power output signal Vo or the voltage feedback signal Vc is greater than or equal to the product of the average value of the charge feedback signal Vcr and the mode switching control coefficient k1, and when each second drive signal Gate_L is adjusted from the first level to the second level, simultaneously use a preset slope compensation slope to perform slope compensation on the voltage feedback signal Vc to obtain a feedback adjustment signal Vcomp; and delay the setting time to adjust the first drive signal Gate_H from the second level to the first level; when the voltage amplitude of the feedback adjustment signal Vcomp is equal to that of the charge feedback signal Vcr, adjust the first drive signal Gate_H from the first level to the second level.

[0083] In other embodiments, the logic control circuit 33 can also specifically perform slope compensation on the voltage feedback signal Vc with a preset slope compensation slope after a delay of a set time when each second drive signal Gate_L is adjusted from the first level to the second level to obtain a feedback adjustment signal Vcomp, and the present application does not limit this.

[0084] It is worth noting that the logic control circuit 33 uses a preset slope compensation slope to perform slope compensation on the voltage feedback signal Vc when each second drive signal Gate_L is adjusted from the first level to the second level. The preset slope compensation slopes corresponding to the slope compensation performed on the voltage feedback signal Vc with the preset slope compensation slope after a delay setting period when each second drive signal Gate_L is adjusted from the first level to the second level are different, and the preset slope compensation slope used for delay is smaller than the preset slope compensation slope used without delay, which is specifically determined by the actual application scenario and is not limited in this application.

[0085] Furthermore, in the second half of each signal cycle, the logic control circuit 33 can specifically copy the first driving signal Gate_H of each first half of the cycle to obtain the second driving signal Gate_L.

[0086] It is understandable that if Figure 4 As shown, in the first half of each signal cycle, specifically, the first drive signal Gate_H has a first level state, and in the second half of each signal cycle, the first drive signal Gate_H continues to be a second level state; and the second drive signal Gate_L continues to be the second level state in the first half of each signal cycle, and in the second half of each signal cycle, the level change state of the first drive signal Gate_H in the first half of each signal cycle is adjusted and copied to obtain the level change state of the second drive signal Gate_L.

[0087] In some embodiments, the set duration may specifically be a preset minimum dead time Td-min, or may be a specific duration reasonably set based on the preset minimum dead time Td-min and control requirements, and this application does not limit this.

[0088] In some embodiments, the first level may be a high level, and the second level may correspond to a low level or a 0 level; or, the first level may be a low level or a 0 level, and the second level may correspond to a high level, which may be specifically determined by the physical characteristics of each switch tube in the inverter circuit 101, and the present application does not limit this.

[0089] Among them, the logic control circuit 33 is also used to send the first drive signal Gate_H and the second drive signal Gate_L to the first switch sub-circuit 1011 and the second switch sub-circuit 1012 respectively, so that the first switch sub-circuit 1011 and the second switch sub-circuit 1012 change the switch state under the action of the first drive signal Gate_H and the second drive signal Gate_L respectively, thereby adjusting the inverter AC signal to adjust the resonant state of the resonant circuit 102.

[0090] In some embodiments, the resonant conversion circuit 100 specifically also includes a switch freewheeling circuit 104 and a voltage-stabilizing output circuit 105; the first switch sub-circuit 1011 specifically includes a first switch tube Q1, and the second switch sub-circuit 1012 includes a second switch tube Q2; the switch freewheeling circuit 104 includes a first freewheeling capacitor C1, a second freewheeling capacitor C2, a first diode D1, and a second diode D2; the resonant circuit 102 includes a first resonant inductor Lr1, a second resonant inductor Lr2, and a resonant capacitor Cr; the power conversion circuit 103 includes an isolation transformer 1031 and a rectifier circuit 1032, the isolation transformer 1031 includes a primary winding RZ0 and a secondary winding RZ1, the secondary winding RZ1 includes a first sub-secondary winding RZ11 and a second sub-secondary winding RZ12, the rectifier circuit 1032 specifically further includes a third diode D3 and a fourth diode D4; the voltage-stabilizing output circuit 105 includes a voltage-stabilizing capacitor Co.

[0091] Among them, the first end of the first switch tube Q1 is coupled to the first end of the first freewheeling capacitor C1 and the second end of the first diode D1, and is used to couple with the first end of the DC power supply 202, that is, the input power supply Vin has a DC output, the second end of the first switch tube Q1 is coupled to the second end of the first freewheeling capacitor C1, the first end of the first diode D1, the first end of the first resonant inductor Lr1, the first end of the second switch tube Q2, the first end of the second freewheeling capacitor C2, and the second end of the second diode D2, the second end of the second switch tube Q2 is coupled to the second end of the second freewheeling capacitor C2, the first end of the second diode D2, and the first end of the resonant capacitor Cr and is grounded, and is used to couple with the second end of the DC power supply 202, the third end of the first switch tube Q1 and the third end of the second switch tube Q2 are coupled to the logic control circuit 33.

[0092] The second end of the first resonant inductor Lr1 is coupled to the first end of the second resonant inductor Lr2 and the first end of the primary winding RZ0 . The second end of the second resonant inductor Lr2 is coupled to the second end of the primary winding RZ0 , the second end of the resonant capacitor Cr and the current sampling sub-circuit 311 .

[0093] The first end of the third diode D3 is coupled to the first end of the first sub-secondary winding RZ11, the second end of the third diode D3 is coupled to the second end of the fourth diode D4 and the first end of the voltage-stabilizing capacitor Co, and is used to couple to the first end of the load circuit 201, the first end of the fourth diode D4 is coupled to the second end of the second sub-secondary winding RZ12, the second end of the voltage-stabilizing capacitor Co is coupled to the second end of the first sub-secondary winding RZ11 and the first end of the second sub-secondary winding RZ12, and is used to couple to the second end of the load circuit 201.

[0094] In other embodiments, the inverter circuit 101 in the resonant conversion circuit 100 can also be a full-bridge inverter conversion circuit, and the rectifier circuit 1032 can also be a full-bridge rectifier conversion circuit composed of switching tubes; the switch freewheeling circuit 104 specifically also includes a freewheeling resistor (not shown in the figure), and the voltage-stabilizing output circuit 105 specifically also includes a voltage-stabilizing resistor (not shown in the figure); the resonant conversion circuit 100 can also specifically include a power factor correction circuit (not shown in the figure), which is coupled to the inverter circuit 101 and is used to couple with an AC power supply (not shown in the figure), that is, the resonant conversion circuit 100 can also be specifically presented by any other reasonable circuit architecture, and the present application does not limit this.

[0095] In some embodiments, the first switch tube Q1 and the second switch tube Q2 may be specifically a MOS tube, a triode, a thin film transistor, a field effect transistor or any other reasonable switch tube, which is not limited in the present application.

[0096] It is worth noting that, in order to distinguish the two ends of each switch tube except the control end, one of the ends is called the first end and the other end is called the second end. When each switch tube is a triode, the control end, that is, the third end, can be specifically the base, the first end is the collector, and the second end is the emitter; or, the third end can also be specifically the base, the first end is the emitter, and the second end is the collector.

[0097] When the above switch tubes are MOS tubes, thin film transistors or field effect transistors, the third end can be a gate, the first end is a drain, and the second end is a source; or, the third end can be a gate, the first end is a source, and the second end is a drain.

[0098] When each switch tube is a MOS tube, a thin film transistor or a field effect transistor, it can also be a composite transistor or a single transistor, which is not limited in the present application.

[0099] In one embodiment, the soft start control circuit 30 specifically further includes a first proportional filter correction subcircuit (not shown) and a second proportional filter correction subcircuit (not shown). The first proportional filter correction subcircuit is coupled to the integration subcircuit 312 and the voltage bias subcircuit 313 in the charge feedback circuit 31, and is coupled to the logic control circuit 33. The second proportional filter correction subcircuit is coupled to the voltage feedback circuit 32 and the logic control circuit 33.

[0100] Among them, the first proportional filtering and correction sub-circuit is used to obtain the phase-modulated voltage signal sent by the integration sub-circuit 312 and the preset bias voltage Vcm output by the voltage bias sub-circuit 313, so as to superimpose the phase-modulated voltage signal and the preset bias voltage Vcm to obtain the charge feedback signal Vcr, and then compare the charge feedback signal Vcr with the reference value, filter, and correct it in turn to obtain the first filtered signal; the second proportional filtering and correction sub-circuit is used to obtain the voltage feedback signal Vc sent by the voltage feedback circuit 32, and compare the voltage feedback signal Vc with the reference value, filter, and correct it in turn to obtain the second filtered signal, so as to provide a more suitable high-quality input for the logic control circuit 33, thereby effectively optimizing the overall performance and reliability of the soft start control circuit 30 to achieve efficient control.

[0101] The logic control circuit 33 is further used to receive the first filter signal and the second filter signal, so as to use the first filter signal and the second filter signal to respectively correspond to the first startup stage, the second startup stage and the third startup stage to obtain the first control signal, the second control signal and the third control signal, thereby using the first control signal, the second control signal and the third control signal to control the inverter circuit 101.

[0102] See also Figure 7 , Figure 7The difference between the soft start control circuit in this embodiment and the first embodiment of the soft start control circuit provided in this application is that the charge feedback circuit 41 in the soft start control circuit 40 further includes a voltage sampling subcircuit 411 .

[0103] Specifically, the voltage sampling subcircuit 411 is coupled to the resonant circuit 102 and the logic control circuit 43 to sample the resonant capacitor voltage in the resonant output signal from the resonant circuit 102 .

[0104] Among them, the resonant capacitor voltage can be specifically understood as a resonant capacitor Cr voltage signal to characterize the input power. The logic control circuit 43 can also be specifically used to receive the resonant capacitor voltage sent by the voltage sampling sub-circuit 411 to utilize the resonant capacitor voltage, or based on any reasonable adjustment of the resonant capacitor voltage to obtain a charge feedback signal Vcr.

[0105] It is understandable that, in this embodiment, the voltage feedback circuit 42 and the logic control circuit 43 are respectively the same as the voltage feedback circuit 12 and the logic control circuit 13. For details, please refer to Figure 1-4 And the related text content will not be repeated here.

[0106] This application also specifically adopts a soft start control method, see Figure 8 , Figure 8 This is a flow chart of the first implementation of the soft start control method of the present application. Specifically, it may include the following steps: S51: Obtain a resonant output signal and a power output signal.

[0107] It can be understood that the soft start control method in this embodiment controls the start-up of the resonant conversion circuit. The resonant conversion circuit includes an inverter circuit, a resonant circuit and an electric energy conversion circuit, the resonant circuit is coupled to the inverter circuit and the electric energy conversion circuit, and the electric energy conversion circuit is used to couple with the load circuit; the soft start control circuit includes a charge feedback circuit, a voltage feedback circuit and a logic control circuit, the charge feedback circuit is used to couple with the resonant circuit, the voltage feedback circuit is used to couple with the electric energy conversion circuit, and the logic control circuit is coupled with the charge feedback circuit and the voltage feedback circuit, and is used to couple with the inverter circuit.

[0108] Specifically, the charge feedback circuit is used to sample and obtain a resonant output signal from the resonant circuit; and the voltage feedback circuit is used to sample and obtain a power output signal output to the load circuit from the power conversion circuit.

[0109] S52: Obtain a charge feedback signal using the resonant output signal.

[0110] Furthermore, the charge feedback circuit performs one or more of any reasonable signal processing such as voltage regulation, filtering, integral transformation, phase modulation and voltage biasing based on the resonant output signal to obtain a charge feedback signal that can reflect the current charge information of the resonant circuit in real time.

[0111] S53: Obtain a voltage feedback signal using the power supply output signal.

[0112] The voltage feedback circuit obtains the difference between the currently acquired power supply output signal and the target reference voltage, and then adopts a voltage loop or speed loop control strategy or a PI controller based on the difference to obtain a specific output signal for signal regulation, namely, a voltage feedback signal.

[0113] It is worth noting that the target reference voltage can be specifically understood as a reference voltage that varies during the entire startup phase, in which the power supply output signal increases monotonically and linearly from 0 to the target output voltage Vobj under theoretical conditions and stabilizes at the target output voltage Vobj.

[0114] S54: Generate a first control signal using a preset rule.

[0115] The logic control circuit is configured to: in a first startup phase, generate a first control signal corresponding to a preset rule based on a preset program.

[0116] In some embodiments, the first startup stage can be specifically determined according to the set duration, that is, the soft start control circuit is powered on as the starting moment, and the time period T0-T1 of the set running duration is the first startup stage. It can also be determined according to the T0-T1 time period corresponding to the output voltage of the power supply output signal Vo rising from 0V to the preset voltage value. The present application does not limit this.

[0117] Among them, in the initial stage when the resonant conversion circuit receives the power input signal input, it is usually necessary to charge the bootstrap capacitor of the high-side switch tube of the inverter circuit, and the charging time needs to ensure that the bootstrap voltage is sufficient. Therefore, the set duration can be specifically determined by the soft start control circuit to ensure that the bootstrap voltage is sufficient and leave a reasonable margin. This application does not limit this.

[0118] In addition, the preset rule can be to use a preset duty cycle, a preset signal frequency, or a preset number of continuous pulses, and stop sending pulses at other times, and other arbitrary rules to generate the first control signal. It is specifically set and adjusted by the actual control scenario of the soft start control circuit to ensure that the bootstrap voltage is sufficient, and this application does not limit this.

[0119] S55: Regulate the inverter AC signal using the first control signal.

[0120] The logic control circuit is also used to send a first control signal to the inverter circuit so that the inverter circuit changes its switch state under the action of the first control signal to adjust its output signal, that is, the inverter AC signal, and further adjust the operation of the resonant circuit.

[0121] S56: After the power-on setting time, detect whether the power output signal or the voltage feedback signal is less than the product of the average value of the charge feedback signal and the mode switching control coefficient.

[0122] Furthermore, after the power-on setting time, that is, in the second startup stage, the logic control circuit is also used to detect whether the power output signal or the voltage feedback signal is less than the product of the average value of the charge feedback signal and the mode switching control coefficient.

[0123] Among them, if the power output signal or the voltage feedback signal is less than the product of the average value of the charge feedback signal and the mode switching control coefficient, it corresponds to the second startup stage and S57 is executed; if the power output signal or the voltage feedback signal is greater than or equal to the product of the average value of the charge feedback signal and the mode switching control coefficient, it corresponds to the third startup stage and S59 is executed.

[0124] S57: Generate a second control signal using the maximum preset switching frequency and the adjustable dead time.

[0125] Specifically, in the second startup stage, the logic control circuit is also used to receive a charge feedback signal sent by the charge feedback circuit and a voltage feedback signal sent by the voltage feedback circuit, so as to generate a second control signal corresponding to the maximum preset switching frequency and adjustable dead time of the resonant circuit.

[0126] In some embodiments, the adjustable dead time is positively correlated with the difference between the power supply output signal and the target reference voltage, that is, when the difference increases, the adjustable dead time also increases accordingly, so that the duty cycle of the second control signal decreases accordingly, so that a larger resonant output signal appears in the initial stage of startup, and the corresponding power supply output signal is also larger. When the difference between the power supply output signal and the target reference voltage is large, the resonant output signal can be reduced as quickly as possible to effectively achieve soft start.

[0127] S58: Regulate the inverter AC signal using the second control signal.

[0128] The logic control circuit is also used to send a second control signal to the inverter circuit so that the inverter circuit changes its switch state under the action of the second control signal to adjust its output signal, that is, the inverter AC signal, and further adjust the operation of the resonant circuit.

[0129] S59: Perform slope compensation on the voltage feedback signal using a preset slope compensation slope to obtain a feedback regulation signal.

[0130] Specifically, Figure 3 and Figure 4 As shown, in the third startup stage, the logic control circuit performs slope compensation on the voltage feedback signal by using a preset slope compensation slope to obtain a feedback regulation signal.

[0131] S510: Generate a third control signal using the feedback adjustment signal and the charge feedback signal.

[0132] The logic control circuit further compares the feedback adjustment signal with the charge feedback signal to generate a charge feedback signal third control signal based on a difference between the two.

[0133] S511: Regulate the inverter AC signal using the third control signal.

[0134] The logic control circuit is also used to send a third control signal to the inverter circuit so that the inverter circuit changes its switch state under the action of the third control signal to adjust its output signal, that is, the inverter AC signal, and further adjust the operation of the resonant circuit.

[0135] See also Fig. 9 , Fig. 9 yes Figure 8 In one embodiment, the soft start control method of the present application includes not only the above S51-S511, but also some more specific steps. Specifically, the above S52 may also include the following steps: S5211: Obtain a resonant current signal in the resonant output signal.

[0136] Specifically, the charge feedback circuit further includes a current sampling subcircuit, an integration subcircuit and a voltage bias subcircuit. The current sampling subcircuit is coupled to the resonant circuit and the integration subcircuit. The integration subcircuit and the voltage bias subcircuit are coupled to the logic control circuit.

[0137] The current sampling subcircuit is used to sample and obtain a resonant current signal in a resonant output signal from the resonant circuit.

[0138] S5212: The resonant current signal is integrated and adjusted to be a phase-modulated voltage signal.

[0139] The integration subcircuit is used to receive the resonant current signal sent by the current sampling subcircuit, so as to integrate and adjust the resonant current signal to obtain a phase-modulated voltage signal.

[0140] The integral regulation of the resonant current signal by the integrator circuit may specifically be such that the phase of the phase-modulated voltage signal lags the resonant current signal by 90°.

[0141] S5213: Superimpose the preset bias voltage on the phase modulation voltage signal to obtain a charge feedback signal.

[0142] The voltage bias subcircuit is used to generate a preset bias voltage, and the logic control circuit is used to receive the phase modulation voltage signal sent by the integration subcircuit and the preset bias voltage correspondingly output by the voltage bias subcircuit, so as to superimpose the preset bias voltage and the phase modulation voltage signal to obtain a charge feedback signal.

[0143] See also Fig.10 , Fig.10 yes Figure 8 In one embodiment, the soft start control method of the present application further includes some more specific steps in addition to the above S51-S511. Specifically, the above S52 may further include the following steps: S5221: Obtain the resonant capacitor voltage in the resonant output signal.

[0144] Specifically, the charge feedback circuit further includes a voltage sampling subcircuit, which is coupled to the resonant circuit and the logic control circuit, and is used to sample the resonant capacitor voltage in the resonant output signal from the resonant circuit.

[0145] S5222: Obtain a charge feedback signal using the resonant capacitor voltage.

[0146] Among them, the resonant capacitor voltage can be specifically understood as a resonant capacitor voltage signal to characterize the input power. The logic control circuit can also be specifically used to receive the resonant capacitor voltage sent by the voltage sampling sub-circuit to utilize the resonant capacitor voltage, or to obtain a charge feedback signal based on any reasonable adjustment of the resonant capacitor voltage.

[0147] See also Fig.11 , Fig.11 : is a flow chart of the second embodiment of the soft start control method of the present application. The soft start control method of this embodiment is Figure 8 A flowchart of a detailed implementation of the soft start control method in the embodiment of the present invention specifically includes the following steps: S61: Obtain a resonant output signal and a power output signal.

[0148] S62: Obtain a charge feedback signal using the resonant output signal.

[0149] S63: Obtain a voltage feedback signal using the power supply output signal.

[0150] S64: Generate a first control signal using a preset rule.

[0151] S65: Regulate the inverter AC signal using the first control signal.

[0152] S66: After the power-on setting time, detect whether the power output signal or the voltage feedback signal is less than the product of the average value of the charge feedback signal and the mode switching control coefficient.

[0153] S67: Generate a second control signal using the maximum preset switching frequency and the adjustable dead time.

[0154] S68: Regulate the inverter AC signal using the second control signal.

[0155] Among them, S61, S62, S63, S64, S65, S66, S67 and S68 are Figure 8 S51, S52, S53, S54, S55, S56, S57 and S58 are the same. Please refer to S51, S52, S53, S54, S55, S56, S57 and S58 and their related text descriptions for details. I will not repeat them here.

[0156] S69: In the first half of each signal cycle of the third control signal, when the second drive signal is adjusted from the first level to the second level, a delay of a set time length or a preset slope compensation slope is used to perform slope compensation on the voltage feedback signal to obtain a feedback adjustment signal.

[0157] Specifically, the inverter circuit in the resonant conversion circuit further includes a first switch subcircuit and a second switch subcircuit, the first switch subcircuit is coupled to the second switch subcircuit, the resonant circuit and the logic control circuit, and the second switch subcircuit is coupled to the logic control circuit.

[0158] Correspondingly, the third control signal specifically includes a first drive signal and a second drive signal, such as Figure 4 As shown, in the third startup stage, the logic control circuit is specifically used to, in the first half of the signal cycle of each second control signal, respond to the starting moment of this stage, that is, the moment when the power output signal or the voltage feedback signal is greater than or equal to the product of the average value of the charge feedback signal and the mode switching control coefficient, and when each second drive signal is adjusted from the first level to the second level, simultaneously or with a delay setting time, perform slope compensation on the voltage feedback signal using a preset slope compensation slope to obtain a feedback adjustment signal.

[0159] S610: Delaying for a set time to adjust the first driving signal from the second level to the first level.

[0160] The logic control circuit is also used to delay the setting time length to adjust the first driving signal from the second level to the first level.

[0161] S611: When the voltage amplitudes of the feedback adjustment signal and the charge feedback signal are equal, adjusting the first driving signal from the first level to the second level.

[0162] The logic control circuit is also used for adjusting the first driving signal from the first level to the second level when the voltage amplitudes of the feedback adjustment signal and the charge feedback signal are equal.

[0163] S612: In the second half of each signal cycle, copy the first driving signal of each first half cycle to obtain a second driving signal.

[0164] Furthermore, in the second half of each signal cycle, the logic control circuit can specifically copy the first drive signal of each first half of the cycle to obtain the second drive signal.

[0165] S613: Regulate the inverter AC signal using the first drive signal and the second drive signal.

[0166] Specifically, the logic control circuit is also used to send the first drive signal and the second drive signal to the first switch sub-circuit and the second switch sub-circuit respectively, so that the first switch sub-circuit and the second switch sub-circuit change the switching state under the action of the first drive signal and the second drive signal respectively, thereby regulating the inverter AC signal to adjust the resonant state of the resonant circuit.

[0167] The above scheme adopts different control strategies in different startup stages to timely suppress instantaneous impact current in the initial stage of the soft start control circuit startup operation, that is, the initial stage of power-on startup, so as to avoid loss to the circuit; controls are implemented at the maximum preset switching frequency in the second startup stage, and the duty cycle is adjusted in response to the difference between the power supply output signal and the target reference voltage, so that the dynamic response speed is faster and the startup resonant cavity current is smaller; and in the third startup stage, control is implemented by comparing the output values ​​of the charge feedback loop and the voltage feedback loop, which can quickly and accurately control the input power according to the output load, and further improve the dynamic response speed of the loop, the control logic is relatively simple, and can achieve better bandwidth and dynamic performance, and can also accurately control the resonant cavity current, so that the linearity of the output voltage of the resonant conversion circuit that realizes control is also better.

[0168] It is understandable that in some other embodiments, the soft start control circuit specifically includes some other more specific circuit units to be able to implement other more specific control methods. For details, please refer to Figure 1-Figure 7 And related text descriptions will not be repeated here.

[0169] This application also specifically adopts a resonant conversion control circuit, see Fig.12 , Fig.12 Schematic diagram of a framework of an embodiment of a resonant conversion control circuit of the present application. In this embodiment, the resonant conversion control circuit 70 includes a resonant conversion circuit 71 and a soft start control circuit 72 .

[0170] Among them, the resonant conversion circuit 71 specifically also includes an inverter circuit 711, a resonant circuit 712 and an electric energy conversion circuit 713, the resonant circuit 712 couples the inverter circuit 711 and the electric energy conversion circuit 713, the electric energy conversion circuit 713 is used to couple with the load circuit 201, and the soft start control circuit 72 couples the inverter circuit 711, the resonant circuit 712 and the electric energy conversion circuit 713.

[0171] It should be noted that the soft start control circuit 72 described in this embodiment is the soft start control circuit 10, the soft start control circuit 20, the soft start control circuit 30 or the soft start control circuit 40 described in any one of the above embodiments. Figure 1-Figure 7 And the related text content will not be repeated here.

[0172] This application also specifically uses an electronic device, see Fig.13 , Fig.13 Schematic diagram of the framework of an electronic device of the present application. In this embodiment, the electronic device 80 includes a housing 81 and a power supply circuit 82 connected to the housing 81 .

[0173] Optionally, the electronic device 80 may be any reasonable electronic mechanical device such as a server, a computer, an intelligent communication device, etc., and this application does not limit this.

[0174] It should be noted that the power supply circuit 82 described in this embodiment is the soft start control circuit 10, the soft start control circuit 20, the soft start control circuit 30 or the soft start control circuit 40 described in any one of the above embodiments, or the resonant conversion control circuit 70. For details, please refer to Figure 1-Figure 7 , Fig.12 And the related text content will not be repeated here.

[0175] The beneficial effects of the present application are as follows: Different from the prior art, the charge feedback circuit in the soft start control circuit provided by the present application is used to obtain the resonant output signal in the resonant circuit, so as to obtain the charge feedback signal by using the resonant output signal; the voltage feedback circuit obtains the power output signal output by the power conversion circuit to the load circuit, so as to obtain the voltage feedback signal by using the difference between the power output signal and the target reference voltage; the logic control circuit is configured as follows: in the first startup stage, a first control signal is generated by using a preset rule; in the second startup stage, a charge feedback signal sent by the charge feedback circuit and a voltage feedback signal sent by the voltage feedback circuit are received, and a second control signal is generated by using a maximum preset switching frequency and an adjustable dead time; wherein the adjustable dead time is positively correlated with the difference; in the third startup stage, a preset slope compensation slope is used to perform slope compensation on the voltage feedback signal to obtain a feedback adjustment signal, so as to generate a third control signal by using the feedback adjustment signal and the charge feedback signal; the logic control circuit is also used to sequentially convert the first control signal, the second control signal and the third control signal into a second control signal. The control signal is sent to the inverter circuit, so that the inverter circuit sequentially adjusts the inverter AC signal output to the resonant circuit using the first control signal, the second control signal and the third control signal, so that in the initial stage of the soft start control circuit starting operation, that is, the initial stage of power-on startup, different control strategies are adopted in different startup stages to timely suppress the instantaneous impact current to avoid loss to the circuit; by realizing control at the maximum preset switching frequency in the second startup stage, and adjusting the duty cycle in response to the difference between the power supply output signal and the target reference voltage, the dynamic response speed is faster and the startup resonant cavity current is smaller; and in the third startup stage, the control is realized by comparing the output values ​​of the charge feedback loop and the voltage feedback loop, so that the input power can be quickly and accurately controlled according to the output load, and the dynamic response speed of the loop is further improved, the control logic is relatively simple, and better bandwidth and dynamic performance can be achieved, and the resonant cavity current can also be accurately controlled, so that the linearity of the output voltage of the resonant conversion circuit that realizes the control is also better.

[0176] The above description is only an implementation method of the present application, and does not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly used in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A soft start control circuit, applied to the start control of a resonant conversion circuit, wherein the resonant conversion circuit comprises an inverter circuit, a resonant circuit and an electric energy conversion circuit, wherein the resonant circuit is coupled to the inverter circuit and the electric energy conversion circuit, and the electric energy conversion circuit is used to couple with a load circuit, wherein: The soft start control circuit comprises: A charge feedback circuit, used to couple with the resonant circuit to obtain a resonant output signal in the resonant circuit, and to obtain a charge feedback signal using the resonant output signal; a voltage feedback circuit, coupled to the power conversion circuit to obtain a power output signal output by the power conversion circuit to the load circuit, and to obtain a voltage feedback signal using a difference between the power output signal and a target reference voltage; A logic control circuit, coupled to the charge feedback circuit and the voltage feedback circuit, and used to be coupled to the inverter circuit; Wherein, the logic control circuit is configured as follows: In the first startup phase, a first control signal is generated using a preset rule; In the second startup phase, the charge feedback signal sent by the charge feedback circuit and the voltage feedback signal sent by the voltage feedback circuit are received, and a second control signal is generated by using a maximum preset switching frequency and an adjustable dead time; wherein the adjustable dead time is positively correlated with the difference; In the third startup stage, a preset slope compensation slope is used to perform slope compensation on the voltage feedback signal to obtain a feedback adjustment signal, so as to generate a third control signal using the feedback adjustment signal and the charge feedback signal; The logic control circuit is also used to send the first control signal, the second control signal and the third control signal to the inverter circuit in sequence, so that the inverter circuit uses the first control signal, the second control signal and the third control signal in sequence to adjust the inverter AC signal output to the resonant circuit.

2. The soft start control circuit according to claim 1, characterized in that: The logic control circuit is configured to: enter the second startup stage from the first startup stage after a power-on setting time; When the power output signal or the voltage feedback signal is greater than or equal to the product of the average value of the charge feedback signal and the mode switching control coefficient, the third startup phase is entered from the second startup phase.

3. The soft start control circuit according to claim 1, characterized in that: The charge feedback circuit comprises a current sampling subcircuit, an integration subcircuit and a voltage bias subcircuit, wherein the current sampling subcircuit is coupled to the resonant circuit and the integration subcircuit, and the integration subcircuit and the voltage bias subcircuit are coupled to the logic control circuit; Wherein, the current sampling subcircuit is used to sample and obtain the resonant current signal in the resonant output signal; The integration subcircuit is used to receive the resonant current signal sent by the current sampling subcircuit, so as to integrate and adjust the resonant current signal into a phase-modulated voltage signal; The logic control circuit is used to receive the phase modulation voltage signal sent by the integration sub-circuit and the preset bias voltage output by the voltage bias sub-circuit, so as to superimpose the preset bias voltage on the phase modulation voltage signal to obtain the charge feedback signal.

4. The soft start control circuit according to claim 3, characterized in that: The preset bias voltage is greater than or equal to half of the difference between a peak and a trough of the phase modulation voltage signal.

5. The soft start control circuit according to claim 1, characterized in that: The charge feedback circuit comprises a voltage sampling subcircuit, wherein the voltage sampling subcircuit is coupled to the resonant circuit and the logic control circuit to sample and obtain the resonant capacitor voltage in the resonant output signal; The logic control circuit is used to receive the resonant capacitor voltage sent by the voltage sampling sub-circuit, so as to obtain the charge feedback signal using the resonant capacitor voltage.

6. The soft start control circuit according to claim 1, characterized in that: The inverter circuit includes a first switch subcircuit and a second switch subcircuit, the first switch subcircuit is coupled to the second switch subcircuit, the resonant circuit and the logic control circuit, and the second switch subcircuit is coupled to the logic control circuit; Wherein, the third control signal includes a first drive signal and a second drive signal, and the logic control circuit is configured to: in the third startup stage, in the first half cycle of each signal cycle of the third control signal, when the second drive signal is adjusted from the first level to the second level, delay for a set time or simultaneously use a preset slope compensation slope to perform slope compensation on the voltage feedback signal to obtain a feedback adjustment signal; and delay for the set time to adjust the first drive signal from the second level to the first level; when the voltage amplitude of the feedback adjustment signal is equal to that of the charge feedback signal, adjust the first drive signal from the first level to the second level; In the second half of each signal cycle, copying the first drive signal of each first half cycle to obtain the second drive signal; The logic control circuit is also used to send the first drive signal and the second drive signal to the first switch sub-circuit and the second switch sub-circuit respectively, so that the first switch sub-circuit and the second switch sub-circuit change the switch state under the action of the first drive signal and the second drive signal respectively to adjust the inverter AC signal.

7. The soft start control circuit according to any one of claims 1 to 6, characterized in that: The adjustable dead time is the sum of the product of the difference and the dead time adjustment coefficient plus the preset minimum dead time.

8. A soft start control method, applied to the start control of a resonant conversion circuit, characterized in that: The soft start control method comprises: Obtaining a resonant output signal and a power supply output signal; obtaining a charge feedback signal using the resonant output signal; Obtaining a voltage feedback signal using the power supply output signal; Generate a first control signal using a preset rule; Using the first control signal to adjust the inverter AC signal; After the power-on setting time, detecting whether the power output signal or the voltage feedback signal is less than the product of the average value of the charge feedback signal and the mode switching control coefficient; If the power supply output signal or the voltage feedback signal is less than the product, a second control signal is generated using a maximum preset switching frequency and an adjustable dead time; wherein the adjustable dead time is positively correlated with the voltage feedback signal; Using the second control signal to adjust the inverter AC signal; If the power supply output signal or the voltage feedback signal is greater than or equal to the product, performing slope compensation on the voltage feedback signal using a preset slope compensation slope to obtain a feedback regulation signal; generating a third control signal using the feedback adjustment signal and the charge feedback signal; The inverter AC signal is regulated using the third control signal.

9. The soft start control method according to claim 8, characterized in that: The step of obtaining a charge feedback signal by using the resonant output signal comprises: Acquiring a resonant current signal from the resonant output signal; The resonant current signal is integrated and adjusted into a phase-modulated voltage signal; The charge feedback signal is obtained by superimposing a preset bias voltage on the phase modulation voltage signal.

10. The soft start control method according to claim 8, characterized in that: The step of obtaining a charge feedback signal by using the resonant output signal comprises: Obtaining a resonant capacitor voltage in the resonant output signal; The charge feedback signal is obtained by using the resonant capacitor voltage.

11. The soft start control method according to claim 8, characterized in that: The third control signal includes a first drive signal and a second drive signal, and the step of using a preset slope compensation slope to perform slope compensation on the voltage feedback signal to obtain a feedback adjustment signal includes: In the first half of each signal cycle of the third control signal, when the second driving signal is adjusted from the first level to the second level, a delay of a set time length or a preset slope compensation slope is used to perform slope compensation on the voltage feedback signal to obtain a feedback adjustment signal; The step of generating a third control signal by using the feedback adjustment signal and the charge feedback signal comprises: Delaying the set time length to adjust the first driving signal from the second level to the first level; When the voltage amplitudes of the feedback adjustment signal and the charge feedback signal are equal, adjusting the first drive signal from the first level to the second level; In the second half of each signal cycle, copying the first drive signal of each first half cycle to obtain the second drive signal; The step of regulating the inverter AC signal by using the third control signal comprises: The inverter AC signal is adjusted using the first drive signal and the second drive signal.

12. A resonant conversion control circuit, characterized in that: The resonant conversion control circuit includes a resonant conversion circuit and a soft start control circuit, the resonant conversion circuit includes an inverter circuit, a resonant circuit and an electric energy conversion circuit, the resonant circuit is coupled to the inverter circuit and the electric energy conversion circuit, the electric energy conversion circuit is used to couple with a load circuit, and the soft start control circuit is coupled to the inverter circuit, the resonant circuit and the electric energy conversion circuit; Wherein, the soft start control circuit is the soft start control circuit as described in any one of claims 1-7.

13. An electronic device, characterized in that: The electronic device comprises a housing and a power circuit connected to the housing; Wherein, the power supply circuit is a soft start control circuit as described in any one of claims 1 to 7, or a resonant conversion control circuit as described in claim 12.

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