Display device, resonant converter and control method for soft start of power conversion circuit

Abstract

The invention provides a display device, a resonant converter and a control method for soft start of a power conversion circuit, and the method comprises the steps: obtaining a rated output voltage and a preset start period of the power conversion circuit in response to a received start signal; determining a target resistance value of a resistor and a target capacity value of a capacitor of the soft start charging model circuit based on the rated output voltage and a preset starting period, and assigning the resistance value of the resistor and the capacity of the capacitor; and taking the rated output voltage as the input voltage of the soft start charging model circuit, obtaining the voltage at the two ends of the capacitor, and outputting the voltage corresponding to the voltage at the two ends of the capacitor as the output voltage of the power conversion circuit so as to realize the soft start of the power conversion circuit. Specifically, the soft start of the power conversion circuit provided by the invention overcomes the limitation of the traditional hardware RC charging mode on the soft start of the LLC circuit. And the resistance value and the capacitance value in the charging model circuit are adjustable through setting, so that the flexibility and the adaptability of the system are improved.

Description

Technical Field

[0001] The present application relates to the field of circuit control, and in particular to a display device, a resonant converter, and a control method for soft starting of a power conversion circuit. Background Art

[0002] In the soft start process of the traditional LLC (resonant converter) circuit, the hardware RC charging method is often used to set the ramp signal.

[0003] However, this approach has certain limitations, such as increased complexity of hardware circuits, increased costs, and poor flexibility.

[0004] Therefore, the existing LLC circuit soft start method needs to be improved urgently. Summary of the invention

[0005] To solve the above problems, the present application provides a display device, a resonant converter and a control method for soft starting of a power conversion circuit, which can solve the limitations of the existing LLC circuit soft starting.

[0006] In order to solve the above problems, the first technical solution provided by the present application is: to provide a control method for soft starting of a power conversion circuit, comprising: In response to receiving a start signal, obtaining a rated output voltage and a preset start period of the power conversion circuit; Based on the rated output voltage and the preset start-up period, determine the target resistance value of the resistor and the target capacity value of the capacitor of the soft start charging model circuit, and assign values ​​to the resistance value of the resistor and the capacity of the capacitor; wherein the resistor and the capacitor are connected in series; The rated output voltage is used as the input voltage of the soft start charging model circuit, the voltage across the capacitor is obtained, and a voltage corresponding to the voltage across the capacitor is output as the output voltage of the power conversion circuit to achieve soft start of the power conversion circuit.

[0007] In one embodiment, the step of determining a target resistance value of a resistor and a target capacity value of a capacitor of a soft start charging model circuit based on the rated output voltage and the preset start-up period, and assigning a value to the resistance value of the resistor and the capacity of the capacitor includes: Find multiple charging curves of capacitor voltage changing with time under different resistance values ​​and capacitance values, and determine the reference resistance value and reference capacitance value corresponding to the rated output voltage in the preset startup period through the multiple charging curves; wherein the charging curve is exponential; The reference resistance value is determined as the target resistance value, and the reference capacitance value is determined as the target capacitance value.

[0008] In one embodiment, the step of searching for multiple charging curves of capacitor voltage changing with time under different resistance values ​​and capacitance values, and determining, through the multiple charging curves, a reference resistance value and a reference capacitance value corresponding to the preset startup period reaching the rated output voltage, further includes: Establishing the soft start charging model circuit, and setting a plurality of groups of capacitance value and resistance value combinations; The charging formula of the RC circuit is used to simulate the charging of the capacitor through each combination, and a plurality of charging curves of the capacitor voltage changing with time under conditions of different resistance values ​​and capacitance values ​​are obtained.

[0009] In one embodiment, the step of using the rated output voltage as the input voltage of the soft start charging model circuit, obtaining the voltage across the capacitor, and outputting a voltage corresponding to the voltage across the capacitor as the output voltage of the power conversion circuit includes: Outputting a voltage that is the same as the voltage across the capacitor as the output voltage of the power conversion circuit; or A voltage smaller than the voltage across the capacitor is output as the output voltage of the power conversion circuit.

[0010] In one embodiment, the step of outputting a voltage corresponding to the voltage across the capacitor as the output voltage of the power conversion circuit to achieve soft start of the power conversion circuit includes: Determine a pulse width modulation signal corresponding to the voltage across the capacitor; The operation of the switch tube in the power conversion circuit is controlled based on the pulse width modulation signal to achieve soft start of the power conversion circuit.

[0011] In one embodiment, the step of determining the pulse width modulation signal corresponding to the voltage across the capacitor comprises: The duty cycle of the pulse width modulation signal is determined based on the voltage across the capacitor.

[0012] In one embodiment, the step of determining the pulse width modulation signal corresponding to the voltage across the capacitor comprises: The frequency of the pulse width modulation signal is determined based on the voltage across the capacitor.

[0013] In one embodiment, in response to receiving a start signal, the step includes: In response to receiving a power-on signal; or In response to receiving a fault repair signal.

[0014] In order to solve the above problems, the second technical solution provided by the present application is: to provide a resonant converter, comprising: Power conversion circuit; A controller, electrically connected to the power conversion circuit; Wherein, in response to receiving a start signal, the controller executes any one of the control methods described above.

[0015] In order to solve the above problems, the third technical solution provided by the present application is: to provide a display device, comprising: A load, wherein the load includes a light emitting element; The resonant converter as described above is electrically connected to the load to achieve soft starting of the load.

[0016] The beneficial effect of the present application is that, different from the prior art, the control method for soft start of the power conversion circuit provided by the present application obtains the rated output voltage and the preset start cycle of the power conversion circuit in response to receiving the start signal; based on the rated output voltage and the preset start cycle, determines the target resistance value of the resistor and the target capacity value of the capacitor of the soft start charging model circuit, and assigns the resistance value of the resistor and the capacity of the capacitor; wherein the resistor and the capacitor are connected in series; takes the rated output voltage as the input voltage of the soft start charging model circuit, obtains the voltage across the capacitor, and outputs the voltage corresponding to the voltage across the capacitor as the output voltage of the power conversion circuit to realize the soft start of the power conversion circuit. Specifically, the control method for soft start of the power conversion circuit of the present application overcomes the limitations of the traditional hardware RC (capacitor resistance) charging method on the soft start of the LLC circuit. And by setting the resistance value and capacitance value in the charging model circuit to be adjustable, the flexibility and adaptability of the system are increased. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] 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 skilled in the art, other drawings can be obtained based on these drawings without creative work, among which: Figure 1 A schematic diagram of a module of a display device provided in one embodiment of the present application; Figure 2 A schematic diagram of a module of a resonant converter provided in one embodiment of the present application; Figure 3 A flow chart of a control method for soft starting of a power conversion circuit provided in an embodiment of the present application; Figure 4 for Figure 3 A flowchart of an embodiment of step S2; Figure 5 for Figure 3 A flowchart of an embodiment of step S3; Figure 6 A circuit structure diagram of a soft start charging model circuit provided in an embodiment of the present application; Figure 7 for Figure 6 The charging curve diagram of the soft start charging model circuit shown; Figure 8 A charging curve diagram of the resonant converter output provided in one embodiment of the present application. DETAILED DESCRIPTION

[0018] 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.

[0019] In this application, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device comprising a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to these processes, methods, products or devices.

[0020] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments 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.

[0021] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship of the associated objects, indicating that there may be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0022] In the description of the embodiments of the present application, the term "plurality" refers to more than two (including two).

[0023] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, technical terms such as "connection" should be understood in a broad sense, for example, it can be directly connected or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of the present application can be understood according to specific circumstances.

[0024] See also Figure 1 , Figure 1 A schematic diagram of a module of a display device provided in one embodiment of the present application.

[0025] Specifically, the present application provides a display device 1000 including a load 100 and a resonant converter 200 .

[0026] The load 100 includes light-emitting elements, the number of the light-emitting elements is not limited, and the types of the light-emitting elements include but are not limited to LED (light-emitting diode), OLED (organic light-emitting diode), and Micro-LED (micro light-emitting diode).

[0027] In some embodiments, the load 100 may be a light-emitting layer, or the load 100 may be a backlight panel, which is not limited herein.

[0028] The resonant converter 200 is electrically connected to the load 100 to achieve soft start of the load 100 .

[0029] Specifically, the resonant converter 200 is used in the present application to realize soft start of the load 100, which can reduce the large impact current generated at the moment of startup, reduce the damage to the load 100, and protect the light-emitting element. In addition, the resonant converter 200 is used in the present application to realize soft start of the load 100, which can also reduce electromagnetic interference and extend the service life of the light-emitting element.

[0030] See also Figure 2 , Figure 2 A schematic diagram of a module of a resonant converter provided in one embodiment of the present application.

[0031] Specifically, the resonant converter 200 includes a controller 202 and a power conversion circuit 201 which are electrically connected. The power conversion circuit 201 is electrically connected to the load 100 to achieve soft start of the load 100 .

[0032] Among them, the power conversion circuit 201 is an LLC circuit, and the LLC circuit is mainly composed of three parts: an input filter circuit, an LLC resonant circuit, and an output rectifier filter circuit. Among them, the input filter circuit is generally composed of components such as capacitors and inductors, which are used to filter out high-frequency noise and ripples in the input power supply and provide a stable DC input for subsequent circuits. The LLC resonant circuit is the core part of the entire circuit, and is composed of a series inductor, a series capacitor, and a parallel inductor. Among them, the series inductor and the series capacitor constitute a series resonant circuit, which is connected in parallel with the parallel inductor. The output rectifier filter circuit generally uses a diode or a synchronous rectifier to form a rectifier bridge, converts a high-frequency AC signal into a DC signal, and then filters it through components such as capacitors and inductors to obtain a stable DC output voltage, thereby starting the load 100.

[0033] The controller 202 may be a single chip microcomputer, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), etc., which is not limited here.

[0034] In the present application, in order to achieve soft start of the power conversion circuit 201 and further achieve soft start of the load 100 , the controller 202 executes a control method for soft start of the power conversion circuit 201 in response to receiving a start signal.

[0035] See also Figure 3 , Figure 3 A flowchart of a control method for soft starting of a power conversion circuit provided in one embodiment of the present application.

[0036] Specifically, the control method includes: Step S1: in response to receiving a start-up signal, obtaining a rated output voltage and a preset start-up period of the power conversion circuit 201 .

[0037] In one embodiment, the start signal is a power-on signal. For example, the start signal is a power-on signal of the display device 1000. Of course, in practical applications, the resonant converter 200 is not limited to being applied only to the display device 1000, but can also be any other device to which the resonant converter 200 can be applied.

[0038] It should be noted that the power-on signal may be a signal for turning the device on or off; the power-on signal may also be a signal light for the device to switch from a standby state to a working state, which is not limited here.

[0039] In another embodiment, the start signal is a fault recovery signal. For example, the fault recovery signal is a signal for the device to recover from any fault state to an operating state.

[0040] It can be understood that the present application improves the application scenarios of soft start by setting the start signal to a power-on signal or a fault repair signal, increases the reliability and adaptability of the system, and can effectively protect circuits and equipment, especially in the scenario where the device recovers from a fault.

[0041] The rated output voltage is the output voltage of the power conversion circuit 201 , and is also the rated operating voltage of the load 100 .

[0042] The preset startup cycle refers to the soft start cycle, that is, the time for the voltage of the load 100 to change from 0 to the rated working voltage. The preset startup cycle is set according to actual needs. It is intended to reduce the large impact current generated at the moment of startup, reduce damage to the load 100, reduce electromagnetic interference, and extend the service life of the load 100.

[0043] Step S2: based on the rated output voltage and the preset start-up period, determine the target resistance value of the resistor and the target capacity value of the capacitor of the soft start charging model circuit, and assign values ​​to the resistance value of the resistor and the capacity of the capacitor.

[0044] Specifically, the present application determines the target resistance value of the resistor and the target capacitance value of the capacitor of the soft start charging model circuit based on the rated output voltage and the preset start cycle. In this way, the resistance value of the resistor and the capacitance value of the capacitor of the soft start charging model circuit can be flexibly adjusted according to actual needs and scenarios to adapt to different circuit operating conditions and soft start requirements.

[0045] In one embodiment, see Figure 4 , Figure 4 for Figure 3 Flow chart of an embodiment of step S2 in FIG. 1 ; step S2 comprises: Step S21: establishing a soft start charging model circuit and setting a plurality of combinations of capacitance values ​​and resistance values.

[0046] Specifically, in the present application, the controller 202 uses a database to pre-establish a soft start charging model circuit (RC charging circuit), the soft start charging model circuit includes a capacitor and a resistor, and sets a plurality of groups of capacitor value and resistor value combinations.

[0047] Among them, in the soft start charging model circuit, the resistor and the capacitor are connected in series.

[0048] Step S22: using the charging formula of the RC circuit to simulate the charging of the capacitor through each combination, and obtaining multiple charging curves of the capacitor voltage changing with time under conditions of different resistance values ​​and capacitance values.

[0049] Specifically, this step can obtain multiple charging curves by simulation, etc. It should be noted that the multiple charging curves in the present application are all exponential.

[0050] Specifically, the existing charging curve is generally linear, for example, a diagonal line, but since the light intensity perceived by the observer increases exponentially, the existing soft start method does not conform to the observer's experience of light intensity when starting the light-emitting element. In the present application, the charging curve is exponential, which is more in line with the observer's experience of light intensity changes.

[0051] Step S23: searching for multiple charging curves of capacitor voltage changing with time under different resistance and capacitance conditions, and determining a reference resistance value and a reference capacitance value corresponding to the rated output voltage in a preset startup cycle through the multiple charging curves.

[0052] Specifically, based on the preset start-up cycle and the rated output voltage, a charging curve that meets the requirement of reaching the rated output voltage in the preset start-up cycle is searched among multiple charging curves, and then the resistance value and voltage value corresponding to the charging curve are determined.

[0053] Step S24: determining the reference resistance value as the target resistance value, and determining the reference capacitance value as the target capacitance value.

[0054] That is, after step S24, the resistance value of the resistor and the capacity value of the capacitor of the soft start charging model circuit are assigned.

[0055] Step S3: Using the rated output voltage as the input voltage of the soft start charging model circuit, obtaining the voltage across the capacitor, and outputting a voltage corresponding to the voltage across the capacitor as the output voltage of the power conversion circuit 201 to achieve soft start of the power conversion circuit 201.

[0056] Specifically, the voltage across the capacitor that changes with time can be calculated using formula (1). Formula (1) is: ; Wherein, Vc(t) is the voltage across the capacitor that changes with time, Vin is the rated output voltage, R is the target resistance value, C is the target capacitance value, and t is the time variable.

[0057] After each Vc(t) is obtained, a voltage corresponding to Vc(t) is output as the output voltage of the power conversion circuit 201 to achieve soft start of the power conversion circuit 201 .

[0058] In one embodiment, step S3 includes: outputting a voltage that is the same as the voltage across the capacitor as the output voltage of the power conversion circuit 201 .

[0059] In another embodiment, considering the transmission loss, the output voltage of the power conversion circuit 201 may be slightly smaller than the voltage across the capacitor, for example, the output voltage of the power conversion circuit 201 is about 99% of the voltage across the capacitor. Therefore, step S3 includes: outputting a voltage smaller than the voltage across the capacitor as the output voltage of the power conversion circuit 201.

[0060] In one embodiment, see Figure 5 , Figure 5 for Figure 3 In the flowchart of an embodiment of step S3, the step of outputting a voltage corresponding to the voltage across the capacitor as the output voltage of the power conversion circuit 201 to achieve soft start of the power conversion circuit 201 includes: Step S31: determining a pulse width modulation signal corresponding to the voltage across the capacitor.

[0061] In one embodiment, step S31 includes: The frequency of the pulse width modulation signal is determined based on the voltage across the capacitor; and / or the duty cycle of the pulse width modulation signal is determined based on the voltage across the capacitor.

[0062] Specifically, after the voltage Vc(t) across the capacitor is calculated, a pulse width modulation signal is output based on Vc(t), wherein the frequency and / or duty cycle of the pulse width modulation signal is determined based on Vc(t).

[0063] Step S32 : controlling the operation of the switch tube in the power conversion circuit 201 based on the pulse width modulation signal to achieve soft start of the power conversion circuit 201 .

[0064] Specifically, the pulse width modulation signal is used to control the operation of the switch tube in the power conversion circuit 201, so that the power conversion circuit 201 generates a corresponding working voltage, and then the working voltage is used to drive the load 100 electrically connected thereto to operate.

[0065] Finally, at the end of the preset start-up period, the voltage Vc(t) across the capacitor corresponds to a voltage substantially equal to the rated output voltage Vin, thereby achieving soft start.

[0066] Specifically, the control method for soft starting of the power conversion circuit 201 provided in the present application is performed based on the database in the controller 202 and has the following advantages: 1. It overcomes the limitations of the traditional hardware RC charging method for LLC circuit soft start.

[0067] 2. By setting the start signal as a power-on signal or a fault repair signal, the application scenario of soft start is improved, and the reliability and adaptability of the system are increased. Especially in the scenario where the device recovers from a fault, it can effectively protect the circuit and equipment.

[0068] 3. The resistance and capacitance values ​​in the charging model circuit are adjustable and can be precisely adjusted according to different application scenarios and requirements, increasing the flexibility and adaptability of the system.

[0069] The present application also provides a specific implementation of a control method for soft starting of a power conversion circuit 201 .

[0070] The first step is system initialization.

[0071] When the system starts, the controller 202 reads the rated output voltage Vin of the power conversion circuit 201 and the preset start-up period, and sets the target resistance value of the resistor, the target capacity value of the capacitor and the time variable in the soft start charging model circuit.

[0072] For details, see Figure 6 and Figure 7 , Figure 6 A circuit structure diagram of a soft start charging model circuit provided in an embodiment of the present application, Figure 7 for Figure 6 The charging curve diagram of the soft start charging model circuit shown in FIG. 1 ; the circuit includes a resistor and a capacitor connected in series. The calculation method of the target resistance value R of the resistor and the target capacitance value C of the capacitor in the soft start charging model circuit is as follows: Assuming the preset startup cycle time is 125ms, for an RC charging circuit, it takes about 5 time constants τ to reach about 99% of the rated output voltage Vin, because each time constant theoretically charges the capacitor to about 63.2% of its rated output voltage, and at 5τ the capacitor is basically charged to 99.3%. Time constant τ = R * C, given the preset startup cycle is 5τ = 125ms, so: R*C = 125 / 5= 25ms.

[0073] By searching the charging curve in the database, the reference resistance value and the reference capacitance value corresponding to the rated output voltage Vin in the preset startup cycle are determined. For example, selecting R=5K and C=5uF in the charging curve can meet the requirements.

[0074] The second step is to simulate the RC charging calculation using the soft start charging model circuit: The controller 202 calculates the capacitor voltage Vc every 500uS based on the set target resistance value R of the resistor and the target capacitance value C of the capacitor using the RC circuit charging formula (the above formula (1)) in the mathematical library function in the controller.

[0075] Among them, the time variable t increases by 1 every 500uS. When t = 250, it means that 125mS has passed and the preset startup cycle is completed.

[0076] Step 3: Vc(t) signal output: The calculated voltage value Vc(t) across the capacitor is used as the voltage setting value of the power conversion circuit 201 , and a pulse width modulation signal is output to control the on and off of the power switch device in the power conversion circuit 201 .

[0077] See also Figure 8 , Figure 8 This is a charging curve diagram of the resonant converter output provided in one embodiment of the present application. In this way, the voltage of the load 100 will rise along with Vc(t) until the preset start-up period ends and the voltage of the load 100 is equal to the rated output voltage Vin, thereby realizing a soft start process for the load.

[0078] The above are only implementation methods of the present application, and are not intended to 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 applied in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A control method for soft starting of a power conversion circuit, characterized in that: include: In response to receiving a start signal, obtaining a rated output voltage and a preset start period of the power conversion circuit; Based on the rated output voltage and the preset start-up period, determine the target resistance value of the resistor and the target capacity value of the capacitor of the soft start charging model circuit, and assign values ​​to the resistance value of the resistor and the capacity of the capacitor; wherein the resistor and the capacitor are connected in series; The rated output voltage is used as the input voltage of the soft start charging model circuit, the voltage across the capacitor is obtained, and a voltage corresponding to the voltage across the capacitor is output as the output voltage of the power conversion circuit to achieve soft start of the power conversion circuit.

2. The control method according to claim 1, characterized in that: The step of determining a target resistance value of a resistor and a target capacity value of a capacitor of a soft start charging model circuit based on the rated output voltage and the preset start-up period, and assigning a value to the resistance value of the resistor and the capacity of the capacitor comprises: Find multiple charging curves of capacitor voltage changing with time under different resistance values ​​and capacitance values, and determine the reference resistance value and reference capacitance value corresponding to the rated output voltage in the preset startup period through the multiple charging curves; wherein the charging curve is exponential; The reference resistance value is determined as the target resistance value, and the reference capacitance value is determined as the target capacitance value.

3. The control method according to claim 2, characterized in that: Before the step of searching for a plurality of charging curves of capacitor voltage varying with time under conditions of different resistance values ​​and capacitance values, and determining, through the plurality of charging curves, a reference resistance value and a reference capacitance value corresponding to the preset startup period reaching the rated output voltage, the step further includes: Establishing the soft start charging model circuit, and setting a plurality of groups of capacitance value and resistance value combinations; The charging formula of the RC circuit is used to simulate the charging of the capacitor through each combination, and a plurality of charging curves of the capacitor voltage changing with time under conditions of different resistance values ​​and capacitance values ​​are obtained.

4. The control method according to any one of claims 1 to 3, characterized in that: The step of using the rated output voltage as the input voltage of the soft start charging model circuit, obtaining the voltage across the capacitor, and outputting a voltage corresponding to the voltage across the capacitor as the output voltage of the power conversion circuit comprises: Outputting a voltage that is the same as the voltage across the capacitor as the output voltage of the power conversion circuit; or A voltage smaller than the voltage across the capacitor is output as the output voltage of the power conversion circuit.

5. The control method according to claim 1, characterized in that: The step of outputting a voltage corresponding to the voltage across the capacitor as the output voltage of the power conversion circuit to achieve soft start of the power conversion circuit includes: Determine a pulse width modulation signal corresponding to the voltage across the capacitor; The operation of the switch tube in the power conversion circuit is controlled based on the pulse width modulation signal to achieve soft start of the power conversion circuit.

6. The control method according to claim 5, characterized in that: The step of determining the pulse width modulation signal corresponding to the voltage across the capacitor comprises: The duty cycle of the pulse width modulation signal is determined based on the voltage across the capacitor.

7. The control method according to claim 5, characterized in that: The step of determining the pulse width modulation signal corresponding to the voltage across the capacitor comprises: The frequency of the pulse width modulation signal is determined based on the voltage across the capacitor.

8. The control method according to claim 1, characterized in that: The step of responding to receiving a start signal comprises: In response to receiving a power-on signal; or In response to receiving a fault repair signal.

9. A resonant converter, characterized in that: include: Power conversion circuit; A controller, electrically connected to the power conversion circuit; Wherein, in response to receiving a start signal, the controller executes the control method described in any one of claims 1 to 8.

10. A display device, characterized in that: include: A load, wherein the load includes a light emitting element; The resonant converter according to claim 9, electrically connected to the load, and configured to implement a soft start of the load.

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