Capacitive load starting circuit and electronic equipment

Abstract

A capacitive load starting circuit and an electronic device belong to the technical field of power supplies, and output a first control voltage through a current control circuit when the current of an output direct current is smaller than a first preset current; the voltage control circuit outputs a second control voltage when the voltage of the power supply direct current is greater than a first preset voltage; the output circuit adjusts the on resistance of the switching tube according to the first control voltage so as to control the current of the output direct current output by the switching tube to be smaller than a preset threshold value, and controls the switching tube to transmit the input direct current according to the second control voltage so as to output the input direct current to the energy storage circuit as the output direct current; the energy storage circuit is charged according to the output direct current so as to output power supply direct current to supply power to a capacitive load; therefore, the safety and the reliability of the capacitive load starting circuit are improved, and the efficiency in a high-power application scene is improved.

Description

Technical Field

[0001] This application belongs to the technical field of power circuits, and particularly relates to a capacitive load startup circuit and an electronic device. Background Art

[0002] When the power supply output voltage is established, it charges its own energy storage capacitor and the capacitive load at the subsequent stage, and a large current is generated. This current may cause the power supply system to be unstable, and in severe cases, it may even damage the components in the circuit. Generally, the method of connecting a series resistor is often used to limit the transient current, but this method will increase the loss of the steady-state circuit. Therefore, a relay is usually used in parallel with the series resistor to reduce the steady-state power consumption. However, the short service life and arc discharge of the relay will affect the reliability.

[0003] To solve the above problems, a related capacitive load startup circuit includes a diode component, an optocoupler control circuit, a switching circuit, an anti-reverse connection circuit, and an overcurrent protection circuit; the diode component conducts the input direct current unidirectionally, and the optocoupler control circuit controls the optocoupler to turn on through a control signal; the switching circuit controls the turn-on of the switching transistor and the charging time of the capacitor by the turn-on or turn-off of the triode to achieve a soft start function; the anti-reverse connection circuit has the function of preventing the power supply from being reversely connected; the overcurrent protection circuit prevents the current from being too large and plays a role in overcurrent protection.

[0004] However, although the soft start function is achieved by adding a capacitor to the gate-source voltage of the switching transistor, the charging current is uncontrollable when the MOS transistor charges the capacitor at the subsequent stage, and there is a risk that the switching transistor exceeds the safe operating area; moreover, the main power circuit uses a diode component and a switching transistor in series, resulting in low efficiency in high-current application scenarios; at the same time, the impact of the inrush current during the power supply startup stage cannot be eliminated.

[0005] Therefore, the related capacitive load startup circuit has low safety and reliability, and cannot improve the efficiency in high-current scenarios. Summary of the Utility Model

[0006] In view of the above problems, this application provides a capacitive load startup circuit and an electronic device, aiming to solve the problems that the related capacitive load startup circuit has low safety and reliability and cannot improve the efficiency in high-current scenarios.

[0007] In a first aspect, this application provides a capacitive load startup circuit according to an embodiment of this application, which is connected to a capacitive load and includes a current control circuit, a voltage control circuit, an output circuit, a switching transistor, and an energy storage circuit;

[0008] The current control circuit is configured to output a first control voltage in response to the current of the output direct current being less than a first preset current;

[0009] The voltage control circuit is configured to output a second control voltage in response to the voltage of the supplied direct current being greater than a first preset voltage;

[0010] The output circuit is connected to the switching transistor, the current control circuit, and the voltage control circuit, and is configured to adjust the on-resistance of the switching transistor according to the first control voltage to control the current of the output direct current output by the switching transistor to be less than a preset threshold, and control the switching transistor to transfer the input direct current according to the second control voltage, so as to output the input direct current as the output direct current to the energy storage circuit;

[0011] The energy storage circuit is connected to the current control circuit and the voltage control circuit, and is configured to be charged according to the output direct current to output the supplied direct current, and the supplied direct current is used to supply power to the capacitive load.

[0012] In the technical solution of the embodiment of the present application, when the voltage of the supplied direct current is less than the first preset voltage, the current control circuit outputs a first control voltage in response to the current of the output direct current being less than the first preset current, and the output circuit adjusts the on-resistance of the switching transistor according to the first control voltage to control the current of the output direct current output by the switching transistor to be less than the preset threshold, so that when charging the subsequent capacitor (energy storage circuit), the power device (switching transistor) operates in a high-resistance state, the charging current is limited, the charging current is controllable, the influence of the impact current formed by the large-capacitance charging of the capacitive load during the startup of the capacitive load is eliminated, the reliability and safety of the capacitive load startup circuit are improved, and at the same time, the energy storage circuit can be designed as a large capacitor, thereby improving the dynamic adjustment ability of the output; when the voltage of the supplied direct current is greater than the first preset voltage, the voltage control circuit outputs a second control voltage, and the output circuit controls the switching transistor to transfer the input direct current according to the second control voltage, so as to output the input direct current as the output direct current, so that after the subsequent capacitor (energy storage circuit) is charged, the power device (switching transistor) is fully turned on (low on-impedance), improving the efficiency in high-current application scenarios.

[0013] In some embodiments, the current control circuit includes:

[0014] A current sampling circuit is connected to the switching transistor, the voltage control circuit, and the energy storage circuit, and is configured to sample the current of the output direct current to output a current sampling signal;

[0015] A voltage-controlled voltage source is connected to the current sampling circuit and is configured to output a first voltage according to the current sampling signal;

[0016] A first comparison circuit, connected to the voltage-controlled voltage source and the output circuit, is configured to output the first control voltage in response to the first voltage being less than a second preset voltage.

[0017] By adopting the above solution, when the output direct current is less than a first preset current, the first control voltage is output, and voltage adaptation is performed through a voltage-controlled voltage source, which can be applied to high-power application scenarios.

[0018] In some embodiments, the first comparison circuit includes a first comparator and a first resistor;

[0019] The non-inverting input terminal of the first comparator and the first end of the first resistor are connected and jointly constitute the second preset voltage input terminal of the first comparison circuit to access the second preset voltage;

[0020] The inverting input terminal of the first comparator constitutes the first voltage input terminal of the first comparison circuit and is connected to the voltage-controlled voltage source to access the first voltage;

[0021] The output terminal of the first comparator and the second end of the first resistor are connected and jointly constitute the first control voltage output terminal of the first comparison circuit, which is connected to the output circuit to output the first control voltage.

[0022] The circuit of this first comparison circuit is simple and the cost is relatively low.

[0023] In some embodiments, the voltage control circuit includes:

[0024] A voltage sampling circuit, connected to the switching tube, the current control circuit and the energy storage circuit, is configured to sample the voltage of the supplied direct current to output a sampled voltage;

[0025] A second comparison circuit, connected to the voltage sampling circuit and the output circuit, is configured to output the second control voltage in response to the sampled voltage being greater than a third preset voltage.

[0026] By sampling the above solution, when the voltage of the supplied direct current is less than a first preset voltage, the second control voltage is output; through the voltage sampling circuit for voltage adaptation, the application in high-power scenarios is realized.

[0027] In some embodiments, it further includes:

[0028] A first unidirectional conduction circuit, connected to the current control circuit, the voltage control circuit and the energy storage circuit, is configured to access the supplied direct current and perform unidirectional conduction on the supplied direct current.

[0029] Due to the one-way conduction of the supplied direct current, the possibility of current backflow caused by the capacitive load discharging at the moment of power-off is reduced, further improving safety and reliability.

[0030] In some embodiments, it further includes:

[0031] A soft start circuit, connected to the switching transistor, and outputting a soft start voltage according to the input direct current.

[0032] A second one-way conduction circuit, connected to the first one-way conduction circuit and the soft start circuit, and configured to conduct the soft start voltage in one direction.

[0033] Through the above technical solution, when the power supply starts, the capacitive load is powered by the soft start circuit and the second one-way conduction circuit, improving the power supply efficiency. At the same time, the soft start circuit reduces the possibility of input inrush current occurring, and improves the reliability and safety of the capacitive load start circuit.

[0034] In some embodiments, it further includes:

[0035] A third one-way conduction circuit, connected to the current control circuit and the output circuit, and configured to conduct the first control voltage in one direction;

[0036] A fourth one-way conduction circuit, connected to the voltage control circuit and the output circuit, and configured to conduct the second control voltage in one direction;

[0037] The output circuit is specifically configured to: adjust the on-resistance of the switching transistor according to the first control voltage after one-way conduction, so as to control the current of the output direct current output by the switching transistor to be less than a preset threshold, and control the switching transistor to transmit the input direct current according to the second control voltage after one-way conduction, so as to output the input direct current as the output direct current.

[0038] By conducting the first control signal and the second control signal in one direction, the possibility of the first control signal current flowing back into the chip output port of the voltage control circuit is reduced, and the possibility of the second control signal current flowing back into the chip output port of the current control circuit is also reduced, improving the reliability and safety of the capacitive load start circuit.

[0039] In some embodiments, it further includes:

[0040] A drive circuit, connected to the output circuit, the current control circuit and the voltage control circuit, and configured to amplify the first control voltage or the second control voltage;

[0041] The output circuit is specifically configured as follows: adjusting the on-resistance of the switching transistor according to the amplified first control voltage to control the current of the output direct current output by the switching transistor to be less than a preset threshold, and controlling the switching transistor to transmit the input direct current according to the amplified second control voltage so as to output the input direct current as the output direct current.

[0042] By amplifying the first control signal or the second control signal, the voltages of the first control signal and the second control signal can be adapted to the voltage of a high-power output circuit, realizing the startup of a high-power capacitive load and expanding the application scenarios of the capacitive load startup circuit.

[0043] In some embodiments, the drive circuit includes a first triode and a second triode;

[0044] The collector of the first triode is connected to the second power supply;

[0045] The base of the first triode and the base of the second triode are connected and jointly constitute the first control signal input terminal and the second control signal input terminal of the drive circuit, and are connected to the current control circuit and the voltage control circuit to access the first control signal or the second control signal;

[0046] The emitter of the first triode and the emitter of the second triode are connected and jointly constitute the first control signal output terminal and the second control signal output terminal of the drive circuit, and are connected to the output circuit to output the amplified first control signal or the amplified second control signal;

[0047] The second triode is connected to the power supply ground.

[0048] The above drive circuit is simple and reliable.

[0049] In a second aspect, an embodiment of the present invention further provides an electronic device, and the electronic device includes a capacitive load and the above capacitive load startup circuit.

[0050] By adopting the above solution, since the electronic device includes the capacitive load startup circuit of any of the above solutions, the safety and reliability of the capacitive load startup circuit can be improved, and it can be applied to high-power scenarios.

[0051] The above description is only an overview of the technical solution of this application. In order to be able to understand the technical means of this application more clearly, it can be implemented according to the content of the specification. And in order to make the above and other purposes, features and advantages of this application more obvious and understandable, the following specifically gives the specific implementation manners of this application. Brief Description of the Drawings

[0052] Upon reading the following detailed description of the preferred embodiments, various other advantages and benefits will become apparent to those of ordinary skill in the art. The drawings are only for the purpose of illustrating the preferred embodiments and are not considered to be a limitation of the present application. Moreover, in all the drawings, the same reference numerals are used to denote the same components. In the drawings:

[0053] Figure 1 FIG. 4 is a schematic structural diagram of a capacitive load starting circuit provided by an embodiment of the present application;

[0054] Figure 2 FIG. 5 is another schematic structural diagram of a capacitive load starting circuit provided by an embodiment of the present application;

[0055] Figure 3 FIG. 6 is another schematic structural diagram of a capacitive load starting circuit provided by an embodiment of the present application;

[0056] Figure 4 FIG. 7 is another schematic structural diagram of a capacitive load starting circuit provided by an embodiment of the present application;

[0057] Figure 5 FIG. 8 is another schematic structural diagram of a capacitive load starting circuit provided by an embodiment of the present application;

[0058] Figure 6 FIG. 9 is another schematic structural diagram of a capacitive load starting circuit provided by an embodiment of the present application;

[0059] Figure 7 FIG. 10 is another schematic structural diagram of a capacitive load starting circuit provided by an embodiment of the present application;

[0060] Figure 8 FIG. 11 is a schematic diagram of a partial circuit example of a capacitive load starting circuit provided by an embodiment of the present application. Detailed Embodiments

[0061] The embodiments of the technical solutions of the present application will be described in detail below with reference to the drawings. The following embodiments are only used to illustrate the technical solutions of the present application more clearly, and therefore are only examples and cannot be used to limit the protection scope of the present application.

[0062] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification and claims of this application and the above drawings are intended to cover non-exclusive inclusion.

[0063] In the description of the embodiments of the present application, technical terms such as "first" and "second" are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity, specific order or primary-secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "a plurality of" is more than two, unless otherwise specifically defined.

[0064] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in connection with the embodiments can be included in at least one embodiment of the present application. The phrase appears in various places in the specification and does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive of other embodiments. Those skilled in the art will explicitly and implicitly understand that the embodiments described herein can be combined with other embodiments.

[0065] In the description of the embodiments of the present application, the term "and / or" is merely a description of the association relationship between associated objects, indicating that three relationships can exist. For example, A and / or B can represent three situations: A exists alone, A and B exist simultaneously, and B exists alone. Additionally, the character " / " in this text generally represents an "or" relationship between the associated objects before and after.

[0066] In the description of the embodiments of the present application, the term "a plurality of" refers to more than two (including two). Similarly, "a plurality of groups" refers to more than two groups (including two groups), and "a plurality of pieces" refers to more than two pieces (including two pieces).

[0067] Currently, from the perspective of the development of the market situation, the applications starting with capacitive loads are becoming more and more widespread. Capacitive loads are widely used in transportation means such as electric bicycles, motorcycles, and automobiles, as well as in multiple fields such as military equipment and aerospace. With the continuous expansion of the application fields of capacitive loads, the market demand is also continuously increasing.

[0068] To solve the problems of poor reliability and safety, the applicant has found through research that in the design, during the power startup stage, the on-resistance of the switching tube can be adjusted first to control the current of the output direct current output by the switching tube to be less than a preset threshold. After the output voltage of the energy storage circuit is greater than a first preset voltage, the switching tube is controlled to be fully turned on, thereby improving the safety and reliability of the capacitive load startup circuit and the efficiency in high-power application scenarios.

[0069] The capacitive load starting circuit disclosed in the embodiments of the present application can be used in an electrical device with a capacitive load as the load. The electrical device can be, but is not limited to, an electric toy, an electric tool, a battery car, an electric vehicle, a ship, a spacecraft, and the like. Among them, the electric toy can include a fixed or mobile electric toy, such as a game console, an electric vehicle toy, an electric ship toy, and an electric aircraft toy, etc. The spacecraft can include an airplane, a rocket, a space shuttle, and a spaceship, etc.

[0070] According to some embodiments of the present application, referring to Figure 1 , Figure 1 FIG. shows a schematic structural diagram of a capacitive load starting circuit provided by an embodiment of the present application. For the convenience of description, only the parts related to this embodiment are shown and are described in detail as follows:

[0071] The above capacitive load starting circuit is connected to a capacitive load (not shown in the figure) and includes a current control circuit 11, a voltage control circuit 12, an output circuit 13, a switching transistor 14, and an energy storage circuit 15;

[0072] The current control circuit 11 is configured to output a first control voltage in response to the current of the output direct current being less than a first preset current.

[0073] The voltage control circuit 12 is configured to output a second control voltage in response to the voltage of the supplied direct current being greater than a first preset voltage.

[0074] The output circuit 13 is connected to the switching transistor 14, the current control circuit 11, and the voltage control circuit 12, and is configured to adjust the on-resistance of the switching transistor 14 according to the first control voltage to control the current of the output direct current output by the switching transistor 14 to be less than a preset threshold, and control the switching transistor 14 to transfer the input direct current VIN according to the second control voltage to output the input direct current VIN as the output direct current to the energy storage circuit 15.

[0075] The energy storage circuit 15 is connected to the current control circuit 11 and the voltage control circuit 12, and is configured to be charged according to the output direct current to output a supplied direct current, and the supplied direct current is used to supply power to the capacitive load.

[0076] It can be understood that the power supply outputs and inputs direct current VIN. When the power supply is started, the voltage of the supplied direct current output by the energy storage circuit 15 is less than the first preset voltage. At this time, the voltage control circuit 12 stops outputting the second control voltage in response to the voltage of the supplied direct current being less than or equal to the first preset voltage, while the current control circuit 11 outputs the first control voltage in response to the current of the output direct current being less than the first preset current. The output circuit 13 adjusts the on-resistance of the switching transistor 14 according to the first control voltage to control the current of the output direct current output by the switching transistor 14 to be less than the preset threshold; the output direct current less than the preset threshold charges the energy storage circuit 15 until the output voltage of the energy storage circuit 15 (the voltage of the supplied direct current) is greater than the first preset voltage; at this time, the voltage control circuit 12 outputs the second control voltage in response to the voltage of the supplied direct current being greater than the first preset voltage; the output circuit 13 controls the switching transistor 14 to transmit the input direct current VIN according to the second control voltage to output the input direct current VIN as the output direct current, and the output direct current charges the energy storage circuit 15 to make the energy storage circuit 15 output the supplied direct current, and the supplied direct current supplies power to the capacitive load.

[0077] In the technical solution of the embodiment of the present application, when the voltage of the supplied direct current is less than the first preset voltage, the current control circuit 11 outputs the first control voltage in response to the current of the output direct current being less than the first preset current. The output circuit 13 adjusts the on-resistance of the switching transistor 14 according to the first control voltage to control the current of the output direct current output by the switching transistor 14 to be less than the preset threshold, so that when charging the subsequent capacitor (energy storage circuit 15), the power device (switching transistor 14) operates in a high resistance state, the charging current is controllable, the influence of the inrush current is eliminated, the reliability and safety of the capacitive load starting circuit are improved, and at the same time, the energy storage circuit 15 can be designed as a large capacitor, thereby improving the dynamic adjustment ability of the output; when the voltage of the supplied direct current is greater than the first preset voltage, the voltage control circuit 12 outputs the second control voltage, and the output circuit 13 controls the switching transistor 14 to transmit the input direct current VIN according to the second control voltage to output the input direct current VIN as the output direct current, so that after the subsequent capacitor (energy storage circuit 15) is charged, the power device (switching transistor 14) is fully turned on (low on-impedance), improving the efficiency in high-current application scenarios.

[0078] In some embodiments, optionally, please continue to refer to Figure 2 , the current control circuit 11 includes a current sampling circuit 111, a voltage-controlled voltage source 112, and a first comparison circuit 113.

[0079] The current sampling circuit 111 is connected to the switching transistor 14, the voltage control circuit 12, and the energy storage circuit 15, and is configured to sample the current of the output direct current to output a current sampling signal.

[0080] A voltage-controlled voltage source 112, connected to the current sampling circuit 111, is configured to output a first voltage according to the current sampling signal.

[0081] A first comparison circuit 113, connected to the voltage-controlled voltage source 112 and the output circuit 13, is configured to output a first control voltage in response to the first voltage being less than a second preset voltage.

[0082] It can be understood that the first comparison circuit 113 is connected to a first reference module, and the first reference module is used to provide the second preset voltage.

[0083] In a specific implementation, the output voltage of the voltage-controlled voltage source 112 is controlled by the input voltage of the voltage-controlled voltage source 112 and satisfies: Uo = u * Ui; where Uo is the output voltage of the voltage-controlled voltage source 112, Ui is the input voltage of the voltage-controlled voltage source 112, and u is a constant.

[0084] The current sampling circuit 111 may include a sampling resistor or a current transformer.

[0085] By adopting the above scheme, when the output direct current is less than the first preset current, the first control voltage is output, and voltage adaptation is performed through the voltage-controlled voltage source 112, which can be applied to high-power application scenarios.

[0086] In some embodiments, optionally, please continue to refer to Figure 3 , the voltage control circuit 12 includes a voltage sampling circuit 121 and a second comparison circuit 122.

[0087] The voltage sampling circuit 121, connected to the switching transistor 14, the current control circuit 11, and the energy storage circuit 15, is configured to sample the voltage of the supplied direct current to output a sampled voltage.

[0088] The second comparison circuit 122, connected to the voltage sampling circuit 121 and the output circuit 13, is configured to output a second control voltage in response to the sampled voltage being greater than a third preset voltage.

[0089] In a specific implementation, the voltage sampling circuit 121 may be a voltage dividing circuit, and the voltage dividing circuit divides the voltage of the supplied direct current to output a sampled voltage.

[0090] It can be understood that the second comparison circuit 122 is connected to a second reference module, and the second reference module is used to provide the third preset voltage.

[0091] By sampling the above scheme, when the voltage of the supplied direct current is less than the first preset voltage, the second control voltage is output; through voltage adaptation by the voltage sampling circuit 121, the application in high-power scenarios is realized.

[0092] According to some embodiments of the present application, optionally, please continue to refer to Figure 4 , Figure 4 which shows a schematic structural diagram of a capacitive load starting circuit provided by another embodiment of the present application. For the sake of convenience of description, only the parts related to this embodiment are shown and are described in detail as follows:

[0093] In addition to all the components and assemblies of the capacitive load starting circuit as shown in Figure 1 , the capacitive load starting circuit further includes a first unidirectional conduction circuit 16.

[0094] The first unidirectional conduction circuit 16 is connected to the current control circuit 11, the voltage control circuit 12, and the energy storage circuit 15, and is configured to access the supply direct current and conduct the supply direct current unidirectionally.

[0095] It can be understood that the first unidirectional conduction circuit 16 may include a diode.

[0096] Since the supply direct current is conducted unidirectionally, the possibility of current backflow caused by the discharge of the capacitive load at the moment of power-off is reduced, and the safety and reliability are further improved.

[0097] According to some embodiments of the present application, optionally, please continue to refer to Figure 5 , Figure 5 which shows a schematic structural diagram of a capacitive load starting circuit provided by another embodiment of the present application. For the sake of convenience of description, only the parts related to this embodiment are shown and are described in detail as follows:

[0098] In addition to all the components and assemblies of the capacitive load starting circuit as shown in Figure 4 , the capacitive load starting circuit further includes a soft start circuit 17 and a second unidirectional conduction circuit 18.

[0099] The soft start circuit 17 is connected to the switching transistor 14 and outputs a soft start voltage according to the input direct current VIN.

[0100] The second unidirectional conduction circuit 18 is connected to the first unidirectional conduction circuit 16 and the soft start circuit 17, and is configured to conduct the soft start voltage unidirectionally.

[0101] It can be understood that the second unidirectional conduction circuit 18 may include a diode. The soft start circuit 17 may include a capacitor.

[0102] It should be noted that since the output ends of the first unidirectional conduction circuit 16 and the second unidirectional conduction circuit 18 are commonly connected and then connected to the capacitive load, the larger of the soft start voltage and the supply direct current supplies power to the capacitive load.

[0103] Through the above technical solution, when the power supply is started, the capacitive load is powered by the soft start circuit 17 and the second unidirectional conduction circuit 18, which improves the power supply efficiency. At the same time, the soft start circuit 17 reduces the possibility of the occurrence of input inrush current and improves the reliability and safety of the capacitive load start circuit.

[0104] According to some embodiments of the present application, optionally, please continue to refer to Figure 6 , Figure 6 FIG. shows a schematic structural diagram of a capacitive load start circuit provided by another embodiment of the present application. For the sake of convenience of description, only the parts related to this embodiment are shown and are described in detail as follows:

[0105] In addition to all the components and assemblies of the capacitive load start circuit as shown in Figure 1 , the capacitive load start circuit further includes a third unidirectional conduction circuit 19 and a fourth unidirectional conduction circuit 20.

[0106] The third unidirectional conduction circuit 19 is connected to the current control circuit 11 and the output circuit 13 and is configured to conduct the first control voltage unidirectionally.

[0107] The fourth unidirectional conduction circuit 20 is connected to the voltage control circuit 12 and the output circuit 13 and is configured to conduct the second control voltage unidirectionally.

[0108] The output circuit 13 is specifically configured to: adjust the on-resistance of the switching transistor 14 according to the first control voltage after unidirectional conduction to control the current of the output direct current output by the switching transistor 14 to be less than a preset threshold, and control the switching transistor 14 to transmit the input direct current VIN according to the second control voltage after unidirectional conduction, so as to output the input direct current VIN as the output direct current.

[0109] It can be understood that both the third unidirectional conduction circuit 19 and the fourth unidirectional conduction circuit 20 may include diodes.

[0110] It should be noted that since the output ends of the third unidirectional conduction circuit 19 and the fourth unidirectional conduction circuit 20 are commonly connected and then connected to the output circuit 13, the larger of the first control voltage and the second control voltage is input to the output circuit 13.

[0111] By unidirectionally conducting the first control signal and the second control signal, the possibility of the first control signal current flowing back into the chip output port of the voltage control circuit 12 is reduced, and the possibility of the second control signal current flowing back into the chip output port of the current control circuit 11 is also reduced, improving the reliability and safety of the capacitive load start circuit.

[0112] According to some embodiments of the present application, optionally, please continue to refer to Figure 7 ,Figure 7 The structural schematic diagram of the capacitive load starting circuit provided by another embodiment of the present application is shown. For the sake of convenience of description, only the parts related to this embodiment are shown and are described in detail as follows:

[0113] In addition to all the components and assemblies of the capacitive load starting circuit as Figure 1 shown, the capacitive load starting circuit further includes a driving circuit 21.

[0114] The driving circuit 21 is connected to the output circuit 13, the current control circuit 11, and the voltage control circuit 12, and is configured to amplify the first control voltage or the second control voltage.

[0115] The output circuit 13 is specifically configured to: adjust the on-resistance of the switching transistor 14 according to the amplified first control voltage to control the current of the output direct current output by the switching transistor 14 to be less than a preset threshold, and control the switching transistor 14 to transmit the input direct current VIN according to the amplified second control voltage to output the input direct current VIN as the output direct current.

[0116] It should be noted that the driving circuit 21 can be a triode amplifier circuit to amplify the voltage of the first control signal or the second control signal.

[0117] By amplifying the first control signal or the second control signal, the voltages of the first control signal and the second control signal can be adapted to the voltage of the high-power output circuit 13, realizing the start of the high-power capacitive load and expanding the application scenarios of the capacitive load starting circuit.

[0118] In some embodiments, optionally, please continue to refer to Figure 8 , the first comparison circuit 113 includes a first comparator U1 and a first resistor R1;

[0119] The non-inverting input terminal of the first comparator U1 and the first end of the first resistor R1 are connected and jointly form the second preset voltage input terminal of the first comparison circuit 113 to access the second preset voltage.

[0120] The inverting input terminal of the first comparator U1 forms the first voltage input terminal of the first comparison circuit 113 and is connected to the voltage-controlled voltage source 112 to access the first voltage.

[0121] The output terminal of the first comparator U1 and the second end of the first resistor R1 are connected and jointly form the first control voltage output terminal of the first comparison circuit 113, which is connected to the output circuit 13 to output the first control voltage.

[0122] It can be understood that the first resistor R1 plays a role in improving the stability of the first comparison circuit 113.

[0123] The first comparison circuit 113 has a simple circuit and low cost.

[0124] In some embodiments, optionally, please continue to refer to Figure 8 , the driving circuit 21 includes a first triode Q1 and a second triode Q2.

[0125] The collector of the first triode Q1 is connected to the second power supply VBB; the bases of the first triode Q1 and the second triode Q2 are connected and jointly form the first control signal input terminal of the driving circuit 21 and the second control signal input terminal of the driving circuit 21, which are connected to the current control circuit 11 and the voltage control circuit 12 to access the first control signal or the second control signal; the emitters of the first triode Q1 and the second triode Q2 are connected and jointly form the first control signal output terminal of the driving circuit 21 and the second control signal output terminal of the driving circuit 21, which are connected to the output circuit 13 to output the amplified first control signal or the amplified second control signal; the second triode Q2 is connected to the power ground.

[0126] In specific implementation, the driving circuit 21 may further include a third capacitor C3; the first end of the third capacitor C3 is connected to the second power supply VBB and the collector of the first triode Q1, and the second end of the third capacitor C3 is connected to the power ground.

[0127] It should be noted that the driving circuit 21 including the first triode Q1 and the second triode Q2 has a high voltage amplification factor.

[0128] The above driving circuit 21 is simple and reliable.

[0129] In some embodiments, optionally, please continue to refer to Figure 8 , the output circuit 13 is specifically configured to further amplify the amplified first control signal of the driving circuit 21 and the amplified second control signal of the driving circuit 21 to output the further amplified first control signal and the further amplified second control signal; wherein, the further amplified first control signal is used to adjust the on-resistance of the switching tube 14 to control the current of the output direct current output by the switching tube 14 to be less than a preset threshold; the further amplified second control signal is used to control the switching tube 14 to transmit the input direct current VIN to output the input direct current VIN as the output direct current.

[0130] The switching transistor 14 is a first field-effect transistor M1; the source of the first field-effect transistor M1 serves as the input DC power supply VIN input terminal of the switching transistor 14 to connect to the input DC power supply VIN; the drain of the first field-effect transistor M1 serves as the output DC power supply output terminal of the switching transistor 14 and is connected to the current control circuit 11 to output the output DC power supply; the gate of the first field-effect transistor M1 serves as the first control signal input terminal and the second control signal input terminal of the switching transistor 14 and is connected to the output circuit 13 to connect to the first control signal after being amplified again or the second control signal after being amplified again.

[0131] The output circuit 13 includes a second field-effect transistor M2, a third resistor R3, and a fourth resistor R4; the first end of the fourth resistor R4 constitutes the first control signal input terminal and the second control signal input terminal of the output circuit 13 and is connected to the drive circuit 21 to connect to the amplified first control signal or the amplified second control signal; the second end of the fourth resistor R4 is connected to the gate of the second field-effect transistor M2, the drain of the second field-effect transistor M2 is connected to the first end of the third resistor R3, and the second end of the third resistor R3 constitutes the first control signal output terminal and the second control signal output terminal of the output circuit 13 and is connected to the switching transistor 14 to output the first control signal after being amplified again or the second control signal after being amplified again; the source of the second field-effect transistor M2 is connected to the power ground.

[0132] The current sampling circuit 111 includes a second resistor R2; the first end and the second end of the second resistor R2 together constitute the current sampling signal output terminal of the current sampling circuit 111 and are connected to the voltage-controlled voltage source 112 to output the current sampling signal.

[0133] The energy storage circuit 15 includes a first capacitor C1; the first end of the first capacitor C1 constitutes the input DC power supply VIN input terminal and the power supply DC output terminal of the energy storage circuit 15 and is connected to the voltage control circuit 12, the first unidirectional conduction circuit 16, and the current control circuit 11 to connect to the input DC power supply VIN and output the power supply DC.

[0134] The first unidirectional conduction circuit 16 includes a first diode D1; the positive electrode of the first diode D1 constitutes the power supply DC input terminal of the first unidirectional conduction circuit 16 and is connected to the voltage control circuit 12, the energy storage circuit 15, and the current control circuit 11 to connect to the power supply DC; the negative electrode of the first diode D1 constitutes the power supply DC output terminal of the first unidirectional conduction circuit 16 to output the power supply DC after unidirectional conduction.

[0135] The second unidirectional conduction circuit 18 includes a second diode D2; the positive electrode of the second diode D2 forms the soft start voltage input end of the second unidirectional conduction circuit 18, and is connected to the soft start circuit 17 and the switching tube 14 to access the soft start voltage; the negative electrode of the second diode D2 forms the soft start voltage output end of the second unidirectional conduction circuit 18 to output the soft start voltage after unidirectional conduction.

[0136] The soft start circuit 17 includes a second capacitor C2; the first end of the second capacitor C2 forms the input DC voltage VIN input end of the soft start circuit 17 and the soft start voltage output end of the soft start circuit 17, and is connected to the switching tube 14 and the second unidirectional conduction circuit 18 to access the input DC voltage VIN and output the soft start voltage; the first end of the second capacitor C2 is connected to the power ground.

[0137] The third unidirectional conduction circuit 19 includes a third diode D3; the positive electrode of the third diode D3 forms the first control voltage input end of the third unidirectional conduction circuit 19, and is connected to the current control circuit 11 to access the first control voltage; the negative electrode of the third diode D3 forms the first control voltage output end of the third unidirectional conduction circuit 19 to output the first control voltage after unidirectional conduction.

[0138] The fourth unidirectional conduction circuit 20 includes a fourth diode D4; the positive electrode of the fourth diode D4 forms the second control voltage input end of the third unidirectional conduction circuit 19, and is connected to the voltage control circuit 12 to access the second control voltage; the negative electrode of the fourth diode D4 forms the second control voltage output end of the fourth unidirectional conduction circuit 20 to output the second control voltage after unidirectional conduction.

[0139] The voltage sampling circuit 121 includes a fifth resistor R5 and a sixth resistor R6; the first end of the fifth resistor R5 forms the power supply DC voltage input end of the voltage sampling circuit 121, and is connected to the current control circuit 11 and the energy storage circuit 15 to access the power supply DC voltage; the second end of the fifth resistor R5 and the first end of the sixth resistor R6 are connected and jointly form the sampling voltage output end of the voltage sampling circuit 121, and are connected to the second comparison circuit 122 to output the sampling voltage; the second end of the sixth resistor R6 is connected to the power ground.

[0140] The second comparison circuit 122 includes a second comparator U2.

[0141] The inverting input end of the second comparator U2 forms the third preset voltage input end of the second comparison circuit 122 to access the third preset voltage;

[0142] The non-inverting input end of the second comparator U2 forms the sampling voltage input end of the second comparison circuit 122, and is connected to the voltage sampling circuit 121 to access the sampling voltage;

[0143] The output terminal of the first comparator U1 constitutes the second control voltage output terminal of the second comparison circuit 122, and is connected to the output circuit 13 to output the second control voltage.

[0144] It should be noted that the capacitive load starting circuit further includes a second resistor R2; the first end of the second resistor R2 is connected to the cathode of the third diode D3, the cathode of the fourth diode D4, the base of the first triode Q1, and the base of the second triode Q2; the first end of the second resistor R2 is connected to the power ground; the second resistor R2 is used to improve the stability of the voltage at the base of the first triode Q1 and the voltage at the base of the second triode Q2, thereby improving the stability of the capacitive load starting circuit.

[0145] The capacitive load starting circuit further includes a second capacitor C2, a seventh resistor R7, and a voltage stabilizing diode Z1 connected in parallel between the gate and the source of the first field effect transistor M1; the second capacitor C2, the seventh resistor R7, and the voltage stabilizing diode Z1 are used to improve the stability of the gate-source voltage of the first field effect transistor M1.

[0146] The capacitive load starting circuit is connected to the capacitive load 80, and the capacitive load 80 includes a load capacitor CL and a load resistor RL.

[0147] The following combines Figure 8 shown to illustrate its circuit principle:

[0148] The power supply outputs and inputs direct current VIN. When the power supply is started, the voltage of the supplied direct current output by the first capacitor C1 is less than the first preset voltage. At this time, the sampled voltage output by the voltage sampling circuit 121 is less than or equal to the third preset voltage, and the second comparator U2 stops outputting the second control voltage. The current sampling signal is output at both ends of the second resistor R2. The voltage-controlled voltage source 112 outputs a first voltage according to the current sampling signal. When the first voltage is less than the second preset voltage, the first comparator U2 outputs the first control voltage. The first triode Q1 and the second triode Q2 amplify the first control voltage. The second field-effect transistor M2 adjusts the on-resistance of the first field-effect transistor M1 according to the amplified first control voltage to control the current of the output direct current output by the drain of the first field-effect transistor M1 to be less than the preset threshold. The output direct current less than the preset threshold charges the first capacitor C1 until the output voltage of the first capacitor C1 (the voltage of the supplied direct current) is greater than the first preset voltage. At this time, the sampled voltage output by the voltage sampling circuit 121 is greater than the third preset voltage, and the second comparator U2 outputs the second control voltage. The first triode Q1 and the second triode Q2 amplify the second control voltage. The second field-effect transistor M2 controls the first field-effect transistor M1 to transmit the input direct current VIN according to the amplified second control voltage to output the input direct current VIN as the output direct current. The output direct current charges the energy storage circuit 15 so that the energy storage circuit 15 outputs the supplied direct current. The first diode D1 conducts the supplied direct current unidirectionally. It can be understood that in the above process, the second capacitor C2 outputs a soft start voltage according to the input direct current VIN, and the second diode D2 conducts the soft start voltage unidirectionally. The supplied direct current after unidirectional conduction and the soft start voltage after unidirectional conduction jointly supply power to the capacitive load.

[0149] According to some embodiments of the present application, the present application also provides an electronic device, including a capacitive load and the capacitive load starting circuit of any of the above solutions.

[0150] Since the electronic device includes the capacitive load starting circuit of any of the above solutions, the safety and reliability of the capacitive load starting circuit can be improved, and it can be applied to high-power scenarios.

[0151] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than limiting them; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the various embodiments of the present application, and they should all be covered within the scope of the claims and the description of the present application. In particular, as long as there is no structural conflict, the technical features mentioned in each embodiment can be combined in any way. The present application is not limited to the specific embodiments disclosed in the text, but includes all technical solutions that fall within the scope of the claims.

Claims

1. A capacitive load starting circuit, characterized in that, Connected to a capacitive load, including a current control circuit, a voltage control circuit, an output circuit, a switching transistor, and an energy storage circuit; The current control circuit is configured to output a first control voltage in response to the current of the output direct current being less than a first preset current; The voltage control circuit is configured to output a second control voltage in response to the voltage of the supplied direct current being greater than a first preset voltage; The output circuit is connected to the switching transistor, the current control circuit, and the voltage control circuit, and is configured to adjust the on-resistance of the switching transistor according to the first control voltage to control the current of the output direct current output by the switching transistor to be less than a preset threshold, and control the switching transistor to transfer the input direct current according to the second control voltage to output the input direct current as the output direct current to the energy storage circuit; The energy storage circuit is connected to the current control circuit and the voltage control circuit, and is configured to be charged according to the output direct current to output the supplied direct current, and the supplied direct current is used to supply power to the capacitive load.

2. The capacitive load starting circuit according to claim 1, wherein The current control circuit includes: A current sampling circuit, connected to the switching transistor, the voltage control circuit, and the energy storage circuit, and configured to sample the current of the output direct current to output a current sampling signal; A voltage-controlled voltage source, connected to the current sampling circuit, and configured to output a first voltage according to the current sampling signal; A first comparison circuit, connected to the voltage-controlled voltage source and the output circuit, and configured to output the first control voltage in response to the first voltage being less than a second preset voltage.

3. The capacitive load starting circuit according to claim 2, characterized in that, The first comparison circuit includes a first comparator and a first resistor; The positive input terminal of the first comparator and the first end of the first resistor are connected and jointly form the second preset voltage input terminal of the first comparison circuit to access the second preset voltage; The inverting input terminal of the first comparator forms the first voltage input terminal of the first comparison circuit, and is connected to the voltage-controlled voltage source to access the first voltage; The output terminal of the first comparator and the second end of the first resistor are connected and jointly form the first control voltage output terminal of the first comparison circuit, and are connected to the output circuit to output the first control voltage.

4. The capacitive load starting circuit according to claim 1, characterized in that, The voltage control circuit includes: A voltage sampling circuit, connected to the switching transistor, the current control circuit, and the energy storage circuit, and configured to sample the voltage of the supplied direct current to output a sampling voltage; A second comparison circuit, connected to the voltage sampling circuit and the output circuit, and configured to output the second control voltage in response to the sampling voltage being greater than a third preset voltage.

5. The capacitive load starting circuit according to claim 1, wherein It further includes: A first unidirectional conduction circuit, connected to the current control circuit, the voltage control circuit, and the energy storage circuit, and configured to access the supplied direct current and perform unidirectional conduction on the supplied direct current.

6. The capacitive load starting circuit according to claim 5, wherein It further includes: A soft start circuit, connected to the switching transistor, and outputting a soft start voltage according to the input direct current; A second unidirectional conduction circuit, connected to the first unidirectional conduction circuit and the soft start circuit, and configured to perform unidirectional conduction on the soft start voltage.

7. The capacitive load starting circuit according to any one of claims 1 to 6, characterized in that It further includes: The third unidirectional conduction circuit, connected to the current control circuit and the output circuit, is configured to conduct the first control voltage unidirectionally; The fourth unidirectional conduction circuit, connected to the voltage control circuit and the output circuit, is configured to conduct the second control voltage unidirectionally; The output circuit is specifically configured to: adjust the on-resistance of the switching transistor according to the unidirectionally conducted first control voltage to control the current of the output direct current output by the switching transistor to be less than a preset threshold, and control the switching transistor to transfer the input direct current according to the unidirectionally conducted second control voltage to output the input direct current as the output direct current.

8. The capacitive load starting circuit according to any one of claims 1 to 6, characterized in that, It further includes: The drive circuit, connected to the output circuit, the current control circuit, and the voltage control circuit, is configured to amplify the first control voltage or the second control voltage; The output circuit is specifically configured to: adjust the on-resistance of the switching transistor according to the amplified first control voltage to control the current of the output direct current output by the switching transistor to be less than a preset threshold, and control the switching transistor to transfer the input direct current according to the amplified second control voltage to output the input direct current as the output direct current.

9. The capacitive load starting circuit according to claim 8, characterized in that, The drive circuit includes a first triode and a second triode; The collector of the first triode is connected to the second power supply; The base of the first triode and the base of the second triode are connected and jointly form the first control signal input terminal and the second control signal input terminal of the drive circuit, connected to the current control circuit and the voltage control circuit to access the first control signal or the second control signal; The emitter of the first triode and the emitter of the second triode are connected and jointly form the first control signal output terminal and the second control signal output terminal of the drive circuit, connected to the output circuit to output the amplified first control signal or the amplified second control signal; The second triode is connected to the power supply ground.

10. An electronic device, characterized in that, The electronic device includes a capacitive load and the capacitive load starting circuit according to any one of claims 1 to 9.

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