Start-up circuit of switching power supply and control method of start-up circuit

Abstract

The invention belongs to the field of starting circuits, and particularly relates to a starting circuit of a switching power supply and a control method thereof.The circuit comprises a high-order energy taking module and a power supply module, one end of the high-order energy taking module is connected with a high-voltage power supply, the other end of the high-order energy taking module is connected with the power supply module, and the power supply module is connected with a control module; the high-order energy taking module is used for taking power from the high-voltage power supply, and the power supply module is used for transmitting the power taken by the high-order energy taking module to the control module; the control module is connected with the load module, and the control module controls the electronic switch to be closed to supply power to the load module; the power supply module comprises a voltage stabilizing diode and a power supply capacitor, the voltage stabilizing diode is connected with the high-order energy taking module, and the power supply capacitor is connected with the voltage stabilizing diode in parallel. The method has the advantages of being small in starting loss and simple in design.

Description

Technical Field

[0001] The invention belongs to the field of starting circuits, and in particular relates to a starting circuit of a switching power supply and a control method thereof. Background Art

[0002] In the inverter products of solar storage and subway vehicles, when the control unit of the inverter is started, it needs to be powered from the external power supply, that is, the starter circuit, to start the control unit. After the control unit is turned on, the load works normally. After the load works, a power supply will be provided to the control unit to achieve normal operation of the load. The voltage of the inverter is about 1.5KV. The power supply of the inverter control unit generally adopts the solution of high-level energy-taking switching power supply. The high-level energy-taking switching power supply can directly convert the high voltage of 1.5KV into the low voltage required by the control unit, with an output power of several hundred watts.

[0003] In the related technology, there are many ways to implement the startup circuit. For example, a linear voltage regulator circuit such as LDO is used to draw power from a 1.5KV high voltage. After the switching power supply completes the startup, the main power topology realizes self-circulating power supply and reduces the power of the linear voltage regulator circuit, or a small-power switching power supply with a power of about 2W is designed inside the switching power supply to convert 1.5KV to low voltage.

[0004] Regarding the above-mentioned related technologies, a large amount of loss will be generated when starting up through linear voltage regulator circuits such as LDO, and in order to ensure the reliable operation of the circuit, the selected electronic components will be very large in size and require a large PCB area. The principle of a low-power switching power supply is complex, the cost is high, and the PCB area required is also large. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a starting circuit with low loss and simple design for a high-voltage power supply. The present application provides a starting circuit of a switching power supply and a control method thereof.

[0006] A starting circuit of a switching power supply, comprising:

[0007] A high-level energy acquisition module and a power supply module, wherein one end of the high-level energy acquisition module is connected to a high-voltage power supply, and the other end is connected to the power supply module, and the power supply module is connected to a control module;

[0008] The high-level energy acquisition module is used to draw power from the high-voltage power supply, and the power supply module is used to transmit the power drawn by the high-level energy acquisition module to the control module;

[0009] The control module is connected to the load module, and the control module controls the electronic switch to close to supply power to the load module;

[0010] The power supply module includes a voltage regulator diode and a power supply capacitor. The voltage regulator diode is connected to the high-level energy acquisition module, and the power supply capacitor is connected in parallel with the voltage regulator diode.

[0011] Optionally, the high-level energy acquisition module includes:

[0012] n resistors and n capacitors, the n capacitors are connected in series with each other, the n resistors are connected in series with each other, the n resistors and the n capacitors are connected in parallel, one end of the capacitor Cn is grounded, and one end of the resistor Rn is connected to the power supply module.

[0013] Optionally, the voltage regulator diode is connected to a high-level energy acquisition module, and the power supply capacitor is connected in parallel with the voltage regulator diode, including:

[0014] The cathode of the voltage zener diode is connected to the resistor Rn, the anode of the voltage zener diode is grounded, the resistor Rn is connected to one end of the power supply capacitor, the other end of the power supply capacitor is grounded, and the power supply capacitor is connected in parallel with the voltage zener diode.

[0015] Optionally, the control module includes:

[0016] An electronic switch S1 and a control chip, one end of the electronic switch is connected to the power supply capacitor, and the other end is connected to the control chip, and one end of the control chip is grounded.

[0017] Optionally, the electronic switch is a semiconductor switch.

[0018] A control method for a start-up circuit of a switching power supply is applied to a start-up circuit of a switching power supply, comprising:

[0019] Obtain the minimum load voltage and working current of the load module;

[0020] Based on the minimum load voltage and the operating current, obtaining load energy consumption consumed within a preset time;

[0021] Based on the load energy consumption and energy formula, the minimum energy storage of the power supply capacitor is obtained;

[0022] Based on the minimum energy storage, a minimum capacitance of the power supply capacitor is obtained.

[0023] Optionally, obtaining the load power consumed within a preset time based on the minimum load voltage and the operating current includes:

[0024] Based on the operating current and the minimum load voltage, obtaining the operating power of the load module;

[0025] The load energy consumption is obtained based on the working power and the preset time period.

[0026] Optionally, obtaining the capacitance of the power supply capacitor based on the minimum energy storage includes:

[0027] Obtaining the maximum voltage of the power supply capacitor;

[0028] Based on the maximum voltage, the minimum load voltage and a preset time period, obtaining the minimum energy storage of the power supply capacitor;

[0029] Based on the minimum energy storage and the load energy consumption, the minimum capacitance of the power supply capacitor is obtained.

[0030] The present invention also proposes an electronic device, comprising a memory, a processor and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, the method for controlling a start-up circuit of a switching power supply as described above is implemented.

[0031] The present invention further proposes a computer storage medium, wherein the storage medium stores at least one executable instruction, and the executable instruction enables a processor to execute a control method for a start-up circuit of a switching power supply as described in any one of the above items.

[0032] The beneficial effects of the present invention are:

[0033] 1. The energy originally consumed in the voltage-dividing resistor is input into the charging capacitor through the voltage-stabilizing diode, and then the load module is powered and started through the charging capacitor. The starting circuit has low power loss, requires fewer devices, occupies less space, and has high reliability.

[0034] 2. By changing the capacitance of the power supply capacitor, the voltage at the power supply capacitor end and the voltage on the load side, it can be adapted to different load modules, has strong adaptability to the control circuit, and realizes the decoupling between the start circuit and the control circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a schematic diagram of the overall structure of the start-up circuit of the present invention;

[0036] Figure 2 This is a schematic diagram of the circuit structure of the high-level energy acquisition module of the present invention;

[0037] Figure 3 This is a schematic diagram of the circuit structure of the power supply module of the present invention;

[0038] Figure 4 is a circuit diagram of the start-up circuit of the present invention;

[0039] Figure 5 FIG. 2 is another circuit structure schematic diagram of the start-up circuit of the present invention.

[0040] Figure 6 This is a state diagram of the startup circuit when the load module of the present invention is started;

[0041] Figure 7 The present invention is a schematic diagram of a control method for a start-up circuit of a switching power supply. DETAILED DESCRIPTION

[0042] A start-up circuit of a switching power supply, such as Figure 1 ,include:

[0043] A high-level energy acquisition module and a power supply module. One end of the high-level energy acquisition module is connected to a high-voltage power supply, and the other end is connected to the power supply module. The power supply module is connected to the control module.

[0044] The high-level energy acquisition module is used to draw power from the high-voltage power supply, and the power supply module is used to transmit the power drawn by the high-level energy acquisition module to the control module.

[0045] like Figure 2 As shown, the high-level energy acquisition module includes: n resistors and n capacitors, the n capacitors are connected in series with each other, the n resistors are connected in series with each other, the n resistors and the n capacitors are connected in parallel, one end of the capacitor Cn is grounded, and one end of the resistor Rn is connected to the power supply module.

[0046] Specifically, suppose that n capacitors are capacitor C1, capacitor C2, capacitor C3, and capacitor Cn, and n resistors are resistors R1, resistor R2, resistor R3, and resistor Rn, one end of capacitor C1 is connected to a high-power supply, the other end of capacitor C1 is connected in series with capacitor C2, capacitor C2 is connected in series with capacitor C3, and all capacitors are connected in series until n capacitors are connected in series. Similarly, resistors are connected in series, one end of resistor R1 is connected to a high-power supply, the other end of resistor R1 is connected in series with resistor R2, and all resistors are connected in series until n resistors are connected in series. Capacitor Cn is grounded, and capacitor Cn is the capacitor at the end of several capacitors connected in series.

[0047] The control module is connected to the load module, and the control module controls the electronic switch to close to supply power to the load module.

[0048] The power supply module includes a voltage regulator diode and a power supply capacitor. The voltage regulator diode is connected to the high-level energy acquisition module, and the power supply capacitor is connected in parallel with the voltage regulator diode.

[0049] The voltage regulator diode is connected to the high-level energy acquisition module, and the power supply capacitor is connected in parallel with the voltage regulator diode, including:

[0050] The cathode of the voltage zener diode is connected to the resistor Rn, the anode of the voltage zener diode is grounded, the resistor Rn is connected to one end of the power supply capacitor, the other end of the power supply capacitor is grounded, and the power supply capacitor is connected in parallel with the voltage zener diode.

[0051] Specifically, Figure 3As shown, the resistor Rn is the terminal resistor of several resistors connected in series, the resistor Rn is connected to the cathode of the Zener diode, the anode of the Zener diode is grounded, the resistor Rn is connected in series with the power supply capacitor C4, the other end of the power supply capacitor C4 is grounded, one end of the power supply capacitor C4 is connected to the anode of the Zener diode VS1, and the other end of the power supply capacitor C4 is connected to the cathode of the Zener diode VS1.

[0052] The resistor Rn is connected to the electronic switch S1, the electronic switch S1 is connected to the load module, and the electronic switch is also connected to the control module. The control module can be the control circuit of the electronic switch S1. When the voltage across the power supply capacitor reaches the requirement, the control circuit of the electronic switch S1 (it can also be controlled by the control chip) controls the electronic switch S1 to close so as to power the load module.

[0053] like Figure 4 As shown, the voltage stabilizing diode VS1 can be replaced by a TL431 circuit. By adjusting the resistance of the two voltage sampling resistors of TL431, the voltage value of Vcc1 can be adjusted flexibly and accurately. The electronic switch S1 can be an NMOS, PMOS or mechanical switch. If S1 is a MOS, the overcurrent protection function of S1 can be achieved by increasing the Maitreya capacitance between the gate and drain gd. If the electronic switch S1 is replaced by a mechanical switch, the overcurrent protection function can be achieved by increasing the series resistance on VCC2.

[0054] The working principle of a starting circuit of a switching power supply is as follows: a high-level energy acquisition module formed by connecting a plurality of resistors in series and a plurality of capacitors in series and connecting the resistors and capacitors in parallel filters the high-level power supply. At the same time, a voltage zener diode VS1 is connected in series between the resistor Rn and the ground. The voltage zener diode VS1 is used to use the electric energy originally completely consumed in the voltage-equalizing resistor for the starting circuit, so as to achieve the purpose of high-level energy acquisition. Moreover, since the voltage of the voltage zener diode VS1 is generally less than tens of volts and the voltage on Cn is hundreds of volts, after being connected in series with VS1, the impact on the input capacitor voltage equalization is very small. Since the resistor Rn is connected to the negative pole of the voltage zener diode, the current will flow to the power supply capacitor C4, so that the power supply capacitor stores energy. When the energy storage of the power supply capacitor reaches a certain voltage, the control circuit of the electronic switch S1 controls the electronic switch S1 to close (when not started, the electronic switch S1 is in a normally open state). After the electronic switch S1 is closed, the load module is powered on and started.

[0055] like Figure 5As shown, when the high-voltage power supply Vin is powered on, the voltage of capacitor C4 reaches the target voltage V1, and the "S1 control circuit" drives S1 to conduct, so that the electric energy stored in capacitor C4 directly supplies power to the control circuit of the power supply (where the target voltage V1 is less than the maximum operating voltage of the control circuit, and also needs to be less than the maximum operating voltage of the voltage-stabilizing diode VS1). When S1 is turned on, the voltage of capacitor C4 begins to drop, so the capacity of capacitor C4 needs to be large enough to support the entire startup process and establish a stable output voltage Vo.

[0056] A control method for a start-up circuit of a switching power supply is applied to a start-up circuit of a switching power supply, comprising:

[0057] S100, obtaining the minimum load voltage and operating current of the load module.

[0058] Specifically, the minimum load voltage at which the load module operates is the minimum operating voltage required for the load module to start, and the operating current is the operating current after the load module is started.

[0059] Based on the working current and the minimum load voltage, the working power of the load module is obtained.

[0060] Specifically, operating power = minimum load voltage * operating current.

[0061] Based on the working power and the preset time period, the load energy consumption is obtained.

[0062] Specifically, load energy consumption = working power * preset time period.

[0063] S110 , based on the minimum load voltage and the operating current, obtain the load energy consumption within a preset time.

[0064] Specifically, the load energy consumption is the energy consumed within a preset time after the load module is started. The preset time is not a specific time period, but an imaginary time. Its purpose is to confirm whether the power supply capacitor can store the energy consumed by the load module startup within the preset time.

[0065] S120: Based on the load energy consumption and the energy formula, the minimum energy storage of the power supply capacitor is obtained.

[0066] Specifically, the energy formula is a formula for determining the energy stored in the power supply capacitor within a preset time period, and the minimum energy storage of the power supply capacitor must be greater than or equal to the load energy consumption.

[0067] S130: Based on the minimum energy storage, obtain the minimum capacitance of the power supply capacitor.

[0068] Specifically, after obtaining the minimum energy storage of the power supply capacitor, the minimum capacitance can be obtained according to the voltage across the power supply capacitor.

[0069] Get the maximum voltage of the supply capacitor.

[0070] Specifically, the maximum voltage of the power supply capacitor is the capacitor voltage after the power supply capacitor is fully charged.

[0071] Based on the highest voltage, the lowest load voltage and the preset time period, the lowest energy storage of the power supply capacitor is obtained.

[0072] Based on the minimum energy storage and load energy consumption, the minimum capacitance of the power supply capacitor is obtained.

[0073] Specifically, as shown in the figure, assume that the target value voltage of the power supply capacitor C4 is V1 (maximum voltage), the minimum operating voltage of the control circuit connected to Vcc2 is V2 (minimum load voltage), the operating current of the load module after startup is Icc, and the rise time of the output voltage Vo of the load module is T1 (preset time period); during the T1 time period, the energy consumed by the load module from Vcc2 is Ps.

[0074]

[0075] During the T1 period, the energy that capacitor C4 needs to store should be greater than or equal to Ps, then:

[0076]

[0077] The capacitance value of C4 is derived as:

[0078]

[0079] Of course, in actual work, in order to ensure that the energy storage of the power supply capacitor can support the startup of the load module, the capacity of the power supply capacitor C4 is usually set larger, such as 1.2 times the calculated value, to ensure that the load module can be fully started.

[0080] The implementation principle of this embodiment is: after the load module is determined, the energy consumption required for the normal startup of the load module is determined, so the minimum energy consumption required to be stored by the power supply capacitor is determined, and the capacitance of the power supply capacitor can be obtained according to the voltage across the power supply capacitor. When the load module is determined, the start-up circuit can automatically adjust the capacity of the power supply capacitor and the voltages of V1 and V2 so that the start-up circuit can support the startup of the load module, and has strong adaptability to the control circuit, realizing the decoupling between the start-up circuit and the control circuit.

[0081] An embodiment of the present application also discloses a terminal device, including a memory and a processor, wherein the memory stores a computer program that can be run on the processor, and when the processor loads and executes the computer program, a control method for a start-up circuit of a switching power supply is adopted.

[0082] The terminal device may be a computer device such as a desktop computer, a laptop computer or a cloud server, and the terminal device includes but is not limited to a processor and a memory. For example, the terminal device may also include input and output devices, a network access device and a bus.

[0083] Among them, the processor can adopt a central processing unit (CPU). Of course, according to actual usage, other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. can also be adopted. The general-purpose processor can adopt a microprocessor or any conventional processor, etc., and this application does not impose any restrictions on this.

[0084] Among them, the memory can be an internal storage unit of the terminal device, such as a hard disk or memory of the terminal device, or it can be an external storage device of the terminal device, such as a plug-in hard disk, a smart memory card (SMC), a secure digital card (SD) or a flash memory card (FC) equipped on the terminal device, etc., and the memory can also be a combination of an internal storage unit and an external storage device of the terminal device. The memory is used to store computer programs and other programs and data required by the terminal device. The memory can also be used to temporarily store data that has been output or is to be output, and this application does not impose any restrictions on this.

[0085] Among them, through this terminal device, a control method for a start-up circuit of a switching power supply in the above embodiment is stored in the memory of the terminal device, and is loaded and executed on the processor of the terminal device for easy use.

[0086] An embodiment of the present application further discloses a computer-readable storage medium, and the computer-readable storage medium stores a computer program, wherein when the computer program is executed by a processor, a control method for a start-up circuit of a switching power supply in the above embodiment is adopted.

[0087] Among them, the computer program can be stored in a computer-readable medium, the computer program includes computer program code, the computer program code can be in the form of source code, object code, executable file or certain middleware, etc. The computer-readable medium includes any entity or device that can carry the computer program code, recording medium, USB flash drive, mobile hard disk, magnetic disk, optical disk, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signal, telecommunication signal and software distribution medium, etc. It should be noted that the computer-readable medium includes but is not limited to the above-mentioned components.

[0088] Among them, through this computer-readable storage medium, a control method for a starting circuit of a switching power supply in the above embodiment is stored in a computer-readable storage medium, and is loaded and executed on a processor to facilitate the storage and application of the above method.

[0089] The above describes specific embodiments of the present invention. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recorded in the claims can be performed in an order different from that in the embodiments and still achieve the desired results. In addition, the processes depicted in the accompanying drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0090] A person skilled in the art should understand that the discussion of any of the above embodiments is merely illustrative and is not intended to imply that the scope of protection of the present application is limited to these examples. In line with the concept of the present application, the technical features in the above embodiments or different embodiments may be combined, the steps may be implemented in any order, and there are many other variations of different aspects of one or more embodiments of the present application as above, which are not provided in detail for the sake of simplicity.

[0091] One or more embodiments of the present application are intended to cover all such substitutions, modifications and variations that fall within the broad scope of the present application. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of one or more embodiments of the present application should be included in the protection scope of the present application.

Claims

1. A starting circuit of a switching power supply, characterized in that: include: A high-level energy acquisition module and a power supply module, wherein one end of the high-level energy acquisition module is connected to a high-voltage power supply, and the other end is connected to the power supply module, and the power supply module is connected to a control module; The high-level energy acquisition module is used to draw power from the high-voltage power supply, and the power supply module is used to transmit the power drawn by the high-level energy acquisition module to the control module; The control module is connected to the load module, and the control module controls the electronic switch to close to supply power to the load module; The power supply module includes a voltage regulator diode and a power supply capacitor. The voltage regulator diode is connected to the high-level energy acquisition module, and the power supply capacitor is connected in parallel with the voltage regulator diode.

2. A starting circuit for a switching power supply as claimed in claim 1, characterized in that: The high-level energy acquisition module comprises: n resistors and n capacitors, the n capacitors are connected in series with each other, the n resistors are connected in series with each other, the n resistors and the n capacitors are connected in parallel, one end of the capacitor Cn is grounded, and one end of the resistor Rn is connected to the power supply module.

3. A starting circuit for a switching power supply as claimed in claim 2, characterized in that: The voltage regulator diode is connected to the high-level energy acquisition module, and the power supply capacitor is connected in parallel with the voltage regulator diode, including: The cathode of the voltage zener diode is connected to the resistor Rn, the anode of the voltage zener diode is grounded, the resistor Rn is connected to one end of the power supply capacitor, the other end of the power supply capacitor is grounded, and the power supply capacitor is connected in parallel with the voltage zener diode.

4. A starting circuit for a switching power supply as claimed in claim 3, characterized in that: The control module comprises: An electronic switch S1 and a control chip, one end of the electronic switch is connected to the power supply capacitor, and the other end is connected to the control chip, and one end of the control chip is grounded.

5. A starting circuit for a switching power supply as claimed in claim 4, characterized in that: The electronic switch is a semiconductor switch.

6. A control method for a start-up circuit of a switching power supply, applied to a start-up circuit of a switching power supply, characterized in that: include: Obtain the minimum load voltage and working current of the load module; Based on the minimum load voltage and the operating current, obtaining load energy consumption consumed within a preset time; Based on the load energy consumption and energy formula, the minimum energy storage of the power supply capacitor is obtained; Based on the minimum energy storage, a minimum capacitance of the power supply capacitor is obtained.

7. A method for controlling a start-up circuit of a switching power supply as claimed in claim 6, characterized in that: The obtaining of the load power consumed within a preset time based on the minimum load voltage and the operating current includes: Based on the operating current and the minimum load voltage, obtaining the operating power of the load module; The load energy consumption is obtained based on the working power and the preset time period.

8. The control method of the start-up circuit of a switching power supply as claimed in claim 6, characterized in that: The obtaining of the capacitance of the power supply capacitor based on the minimum energy storage comprises: Obtaining the maximum voltage of the power supply capacitor; Based on the maximum voltage, the minimum load voltage and a preset time period, obtaining the minimum energy storage of the power supply capacitor; Based on the minimum energy storage and the load energy consumption, the minimum capacitance of the power supply capacitor is obtained.

9. A terminal device, comprising a memory and a processor, characterized in that: The memory stores a computer program that can be run on the processor, and when the processor loads and executes the computer program, the method according to any one of claims 6 to 8 is adopted.

10. A computer-readable storage medium having a computer program stored therein, characterized in that: When the computer program is loaded and executed by a processor, the method according to any one of claims 6 to 8 is adopted.

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