Slow start circuit and communication equipment

Abstract

The utility model relates to the technical field of communication equipment power supply, and provides a slow start circuit and communication equipment, the slow start circuit comprises a slow start control module and an enabling module; the slow start control module is used for connecting an external power supply and a power supply input end of communication equipment, and changing a level signal output by the enabling module when the external power supply is connected; and the enabling module is used for controlling power supply enabling of a post-stage power supply of the communication equipment according to the changed level signal so as to input the external power supply to a post-stage circuit of the communication equipment in a delayed manner. According to the slow start circuit, the power-on time of the communication equipment is prolonged, part of input pulse current is absorbed, the communication equipment is protected, and meanwhile, loss caused by inner resistance of a switching tube in the slow start circuit is avoided.

Description

Technical Field

[0001] The present application relates to the technical field of power supply for communication equipment, and in particular to a soft start circuit and communication equipment. Background Art

[0002] When designing the power supply of communication equipment, a common method is to use DCDC to convert the input power into the multi-branch power supply required by the equipment. However, at the moment of power-on, a large pulse current may be generated, and communication equipment often plugs and unplugs the power-on terminal during use. When plugging and unplugging, the power input will fluctuate, which may cause damage to the power chip. The current design of the power supply power-on slow start circuit is often implemented by connecting a MOS tube in series at the input end. Since the MOS tube has internal resistance when it is turned on, it will generate loss on the MOS tube connected in series to the external power input circuit when it is powered on. Utility Model Content

[0003] In view of this, the purpose of the present application is to provide a slow start circuit and a communication device to achieve slow start of the subsequent circuit of the communication device, while reducing the pulse current when the external power supply is powered on, and solving the problem of excess loss caused by the MOS switch tube being connected in series on the external power supply input circuit in the existing design.

[0004] A soft start circuit provided in an embodiment of the present application includes a soft start control module and an enabling module;

[0005] The soft start control module is used to connect the external power supply and the power input terminal of the communication device, and when the external power supply is connected, changes the level signal output by the enabling module;

[0006] The enabling module is used to control the power supply enabling of the subsequent power supply of the communication device according to the changed level signal, so as to delay the input of the external power supply into the subsequent circuit of the communication device.

[0007] In combination with the first aspect, the embodiment of the present application provides a first possible implementation of the first aspect, wherein the slow start control module includes an energy storage unit, a filter delay unit, a switch unit and a voltage divider unit, the energy storage unit and the voltage divider unit are both connected to the external power supply, the energy storage unit is connected to the switch unit, the switch unit is connected to the filter delay unit, and the filter delay unit is connected to the voltage divider unit;

[0008] The energy storage unit is used to enter a charging state when connected to the external power supply, and is in an open circuit state after charging is completed, so that the enabling module outputs the level signal in a high level state when the energy storage unit is in the open circuit state;

[0009] The filtering delay unit is used to filter out the interference signal of the slow start control module and extend the conduction time of the switch unit;

[0010] The voltage dividing unit is used to divide the voltage of the external power supply to obtain a divided voltage;

[0011] The switch unit is used to be turned on after receiving the divided voltage, so as to conduct the external power supply to the communication device.

[0012] In combination with the first aspect, an embodiment of the present application provides a second possible implementation of the first aspect, wherein the energy storage unit includes an electrolytic capacitor, the positive electrode of the electrolytic capacitor is connected to the power input terminal of the communication device, and the negative electrode of the electrolytic capacitor is connected to the switching unit.

[0013] In combination with the first aspect, an embodiment of the present application provides a third possible implementation of the first aspect, wherein the switching unit includes a switching tube, a drain of the switching tube is connected to the electrolytic capacitor of the energy storage unit, and a source of the switching tube is grounded.

[0014] In combination with the first aspect, an embodiment of the present application provides a fourth possible implementation of the first aspect, wherein the voltage divider unit includes a first voltage divider resistor and a second voltage divider resistor, one end of the first voltage divider resistor is connected to the power input terminal of the communication device, the other end of the first voltage divider resistor is connected to one end of the second voltage divider resistor, and the other end of the second voltage divider resistor is grounded.

[0015] In combination with the first aspect, an embodiment of the present application provides a fifth possible implementation of the first aspect, wherein the filter delay unit includes a filter capacitor, the filter capacitor is connected in parallel with the gate and source of the switching tube, and the filter capacitor is connected in parallel with the second voltage-dividing resistor of the voltage-dividing unit.

[0016] In combination with the first aspect, the embodiment of the present application provides a sixth possible implementation of the first aspect, wherein the enabling module includes a current limiting resistor and a transistor;

[0017] One end of the current limiting resistor is respectively connected to the drain of the switch tube and the negative electrode of the electrolytic capacitor, the other end of the current limiting resistor is connected to the base of the transistor, the collector of the transistor is connected to the enable end of the subsequent circuit, and the emitter of the transistor is grounded.

[0018] In combination with the first aspect, an embodiment of the present application provides a seventh possible implementation of the first aspect, wherein the transistor is used to be in a conducting state when the electrolytic capacitor is charged, the collector of the transistor is at a low level, and an enable signal in a low level state is output to a subsequent circuit of the communication device;

[0019] The transistor is also used to be in a cut-off state after the electrolytic capacitor is completely charged, and the collector of the transistor is converted to a high level to output an enable signal in a high level state to a subsequent circuit of the communication device.

[0020] In a second aspect, an embodiment of the present application further provides a communication device, comprising the above-mentioned soft start circuit.

[0021] In combination with the second aspect, an embodiment of the present application provides a first possible implementation of the second aspect, wherein the communication device further includes a power input terminal and a post-stage circuit respectively connected to both ends of the soft start circuit.

[0022] The embodiments of the present application have the following beneficial effects:

[0023] The slow start circuit of the embodiment of the present application can be used to control the slow start of a communication device when it is connected to an external power supply. The slow start circuit includes a slow start control module and an enable module; the slow start control module is used to connect the external power supply and the power input terminal of the communication device, and when the external power supply is connected, the level signal output by the enable module is changed; the enable module is used to control the power supply enable of the subsequent power supply of the communication device according to the changed level signal, so as to delay the input of the external power supply to the subsequent circuit of the communication device. Based on the above scheme, the slow start circuit realizes a slow start when the communication device is powered on, preventing the instability and fluctuation caused by the large current and voltage jitter during instantaneous startup from affecting the subsequent circuit. At the same time, the slow start circuit can also realize the delay of the enable control of the subsequent circuit, reducing the loss of the communication device, and improving the efficiency and stability of the communication device. At the same time, there is no MOS tube in the slow start circuit connected in series in the circuit, which avoids the loss caused by the internal resistance of the MOS tube in the circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solution of the present application, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present application and should not be regarded as limiting the scope of protection of the present application. In each of the drawings, similar components are numbered similarly.

[0025] Figure 1 A circuit block diagram of a slow start circuit provided in an embodiment of the present application is shown;

[0026] Figure 2 A circuit diagram of a slow start circuit provided in an embodiment of the present application is shown.

[0027] Description of main component symbols:

[0028] 100 - slow start circuit; 110 - slow start control module; 120 - enabling module; 111 - energy storage unit; 112 - filtering delay unit; 113 - switch unit; 114 - voltage dividing unit. DETAILED DESCRIPTION

[0029] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments.

[0030] The components of the embodiments of the present application generally described and shown in the drawings herein may be arranged and designed in various configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the application claimed for protection, but merely represents the selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without making creative work belong to the scope of protection of the present application.

[0031] Hereinafter, the terms "including", "having" and their cognates, which may be used in various embodiments of the present application, are intended only to indicate specific features, numbers, steps, operations, elements, components, or combinations of the foregoing items, and should not be understood as first excluding the existence of one or more other features, numbers, steps, operations, elements, components, or combinations of the foregoing items or adding the possibility of one or more features, numbers, steps, operations, elements, components, or combinations of the foregoing items.

[0032] Furthermore, the terms “first”, “second”, “third”, etc. are merely used for distinguishing descriptions and are not to be understood as indicating or implying relative importance.

[0033] Unless otherwise defined, all terms (including technical terms and scientific terms) used herein have the same meanings as those generally understood by those skilled in the art to which the various embodiments of the present application belong. The terms (such as those defined in generally used dictionaries) will be interpreted as having the same meanings as the contextual meanings in the relevant technical field and will not be interpreted as having idealized meanings or overly formal meanings unless clearly defined in the various embodiments of the present application.

[0034] Example 1

[0035] Please refer to Figure 1, is a structural diagram of a slow start circuit 100 provided in an embodiment of the present application. Exemplarily, the slow start circuit 100 includes a slow start control module 110 and an enable module 120; wherein, the input end of the slow start control module 110 is connected to an external power supply, the slow start control module 110 is used to realize the slow start of the power-on of the rear-stage power supply of the communication device, and the slow start control module 110 is also used to realize the power supply enablement of the rear-stage power supply, wherein the slow start control module 110 includes an energy storage unit 111, a filter delay unit 112, a switch unit 113 and a voltage divider unit 114. The energy storage unit 111 and the voltage divider unit 114 are both connected to the external power supply, the energy storage unit 111 is connected to the switch unit 113, the switch unit 113 is connected to the filter delay unit 112, and the filter delay unit 112 is connected to the voltage divider unit 114.

[0036] In this embodiment, the slow start control module 110 is mainly used to connect the external power supply and the power input terminal of the communication device, and when the external power supply is connected, the level signal output by the enable module 120 is changed. The enable module 120 is mainly used to control the power supply enable of the subsequent power supply of the communication device according to the changed level signal, so as to delay the input of the external power supply into the subsequent circuit of the communication device. The energy storage unit 111 is used to enter the charging state when the external power supply is connected, and is in the open circuit state after the charging is completed, so that the enable module 120 outputs a level signal in the high level state when the energy storage unit 111 is in the open circuit state; the filtering delay unit 112 is used to filter out the interference signal of the slow start control module 110 and extend the conduction time of the switch unit 113; the voltage divider unit 114 is used to divide the external power supply to obtain the divided voltage; the switch unit 113 is used to turn on after receiving the divided voltage to conduct the external power supply to the communication device. Therefore, the soft start circuit 100 in this embodiment enables the communication device to be connected to an external power source, and the external power source first charges the energy storage unit 111 to implement soft start control.

[0037] In order to better understand the soft start circuit 100 according to the embodiment of the present application, the structures of the soft start control module 110 and the enabling module 120 are briefly described here.

[0038] like Figure 1As shown, in this embodiment, the energy storage unit 111 uses an electrolytic capacitor EC1 connected to the positive pole of the external power supply, and the switch tube Q2 in the switch unit 113 is turned on by controlling the positive pole of the external power supply, thereby extending the charging time of the energy storage unit 111, extending the power-on time of the subsequent circuit, and realizing the slow start of the power-on of the subsequent power supply of the communication equipment. Specifically, the charging of the electrolytic capacitor EC1 is a process of connecting an electrolytic capacitor to an external power supply circuit, introducing current through the external power supply, allowing the capacitor to store energy and start charging. When the external power supply is just connected, the electrolytic capacitor EC1 is completely free of charge. At this time, the voltage across the electrolytic capacitor EC1 is zero, which can be regarded as the electrolytic capacitor EC1 being in a short-circuit state. When the external power supply is connected, an instantaneous voltage will be generated, causing the current to flow from the external power supply into the electrolytic capacitor EC1. At this time, the electrolytic capacitor EC1 begins to store charge and voltage and starts to charge. At this time, the switch tube Q2 is turned on, the transistor Q1 of the enabling module 120 is turned on, and the collector of the transistor Q1 outputs a low-level enabling signal, and the enabling output of the subsequent circuit of the communication device is low. The electrolytic capacitor EC1 continues to charge. After charging is completed, the electrolytic capacitor EC1 is in an open circuit state, and the collector of the transistor Q1 can be switched to a high level according to the subsequent power supply. The external power supply starts to supply power to the subsequent power supply of the communication device, realizing the slow start control of the subsequent circuit.

[0039] The enabling module 120 uses a transistor Q1 to control the enabling output of the subsequent power supply of the communication device. Specifically, the base of the transistor Q1 is connected to the negative electrode of the electrolytic capacitor EC1, and the collector of the transistor Q1 is used as the enabling control output. When the electrolytic capacitor EC1 is charged, due to being in a short-circuit state, the base of the transistor Q1 is at a high level, the base voltage is higher than the emitter voltage, the transistor Q1 is turned on, and the collector outputs an enabling signal of a low level to the subsequent power supply. After the electrolytic capacitor EC1 is charged, it is in an open circuit state, the base of the transistor Q1 is switched from a high level to a low level, the transistor Q1 is cut off, and the collector can switch to a high level according to the subsequent power supply, thereby enabling the power supply to the subsequent circuit.

[0040] It can be understood that when the electrolytic capacitor EC1 is charged, the voltage of the electrolytic capacitor EC1 is equal to the base voltage of the transistor Q1, and the transistor Q1 starts to conduct, so that the enable signal outputs a low level, and the subsequent power supply is turned off. When the electrolytic capacitor EC1 finishes charging, the voltage of the base of the transistor Q1 is a low level, and the transistor Q1 is in a cut-off state. When the transistor Q1 is cut off, the collector level of the transistor Q1 will drift to a high level according to the subsequent power supply, so that the subsequent power supply is activated, the enable signal is output, and the enable control of the subsequent circuit is realized.

[0041] The structure and working process of each component in the slow start circuit 100 are described below.

[0042] like Figure 2 As shown, a circuit diagram of a slow start circuit 100 provided in an embodiment of the present application is shown. When the communication device is connected to the external power supply and powered on, the energy storage unit is an electrolytic capacitor EC1, which is in a short-circuit state, and the switch unit is a switch tube Q2, and the drain voltage of the switch tube Q2 is equal to the positive voltage of the electrolytic capacitor EC1. The voltage-dividing unit is a first voltage-dividing resistor R1 and a second voltage-dividing resistor R2, and the first voltage-dividing resistor R1 and the second voltage-dividing resistor R2 are used to divide the voltage of the external power supply. Among them, the switch tube Q2 is an NMOS tube, the gate level of the switch tube Q2 is greater than the source level, and the switch tube Q2 is turned on. At this time, the negative electrode of the electrolytic capacitor EC1 is grounded, and the electrolytic capacitor EC1 is still in a charging state until the electrolytic capacitor EC1 is fully charged, and the electrolytic capacitor EC1 is in an open circuit state. The external power supply starts to supply power to the rear-stage power supply of the communication device, realizing the delayed input of the power supply to the rear-stage power supply, and realizing the slow start function.

[0043] Exemplarily, the filter delay unit 112 is a filter capacitor C1. As a power supply filter element, the filter capacitor C1 can play a certain role in filtering out noise. Its role is mainly reflected in two aspects: smoothing power supply fluctuations: as a capacitor element, the filter capacitor C1 can respond to high-frequency fluctuations in the input power supply in the slow-start circuit 100 and rise the transient current network, playing the role of smoothing the input power supply fluctuations, making the input power supply voltage more stable, thereby avoiding the problem of incorrect switching of the switch tube Q2 due to input power supply fluctuations; filtering out external interference: the filter capacitor C1 can also respond to and filter out high-frequency interference signals in the input power supply, thereby reducing the impact of external noise on the slow-start circuit 100 and improving the anti-interference ability of the slow-start circuit 100.

[0044] At the same time, according to the Miller effect, the filter capacitor C1 is used to increase the driving pulse width of the switch tube Q2, thereby extending the conduction time, making the current rise of the switch tube Q2 when it is turned on and the current drop when it is cut off more moderate, reducing the switching loss and electromagnetic interference of the switch tube Q2, and extending the life of the switch tube Q2.

[0045] Exemplarily, the voltage divider unit 114 uses a first voltage divider resistor R1 and a second voltage divider resistor R2, and is widely used in actual circuit design for voltage division of an external power supply. The working principle of the voltage divider unit 114 is to divide the input external power supply voltage into two different voltages by connecting the first voltage divider resistor R1 and the second voltage divider resistor R2 in series. The voltage divider unit 114 is used to obtain different output voltages by changing the resistance values ​​of the first voltage divider resistor R1 and the second voltage divider resistor R2, thereby meeting different application requirements.

[0046] For example, in one embodiment, the energy storage unit 111 includes an electrolytic capacitor EC1, the positive electrode of the electrolytic capacitor EC1 is connected to the power input terminal of the communication device, and the negative electrode of the electrolytic capacitor EC1 is connected to the switch unit 113. The switch unit 113 includes a switch tube Q2, the drain of the switch tube Q2 is connected to the electrolytic capacitor EC1 of the energy storage unit 111, and the source of the switch tube Q2 is grounded GND. The voltage divider unit 114 includes a first voltage divider resistor R1 and a second voltage divider resistor R2, one end of the first voltage divider resistor R1 is connected to the power input terminal of the communication device, the other end of the first voltage divider resistor R1 is connected to one end of the second voltage divider resistor R2, and the other end of the second voltage divider resistor R2 is grounded GND. The filter delay unit 112 includes a filter capacitor C1, the filter capacitor C1 is connected in parallel to the gate and source of the switch tube Q2 of the switch unit 113, and the filter capacitor C1 is connected in parallel to the second voltage divider resistor R2 of the voltage divider unit 114.

[0047] Exemplarily, the enabling module 120 uses a transistor Q1, which is specifically an NPN transistor. When the external power supply starts to charge the electrolytic capacitor EC1, the electrolytic capacitor EC1 will act as a short circuit, and the resistance value is very small, causing the voltage of the electrolytic capacitor EC1 to rise very quickly. At this time, the base voltage of the transistor Q1 is higher than the emitter voltage, and the transistor Q1 is turned on, thereby pulling the enabling signal low, so that the enabling module 120 outputs a low level to the subsequent circuit, and the subsequent power supply of the communication device is in a closed state. As time goes by, the voltage of the electrolytic capacitor EC1 will slowly rise until it exceeds the base voltage of the transistor Q1, and the transistor Q1 begins to cut off. At this time, the enabling signal can be converted from a low level to a high level, so that the enabling module 120 outputs a high level to the subsequent circuit, starts the subsequent power supply, and thus realizes the enabling control of the subsequent power supply.

[0048] The enabling module 120 also uses a current limiting resistor R3 as the current limiting resistor of the base of the transistor Q1. In the base input circuit of the transistor Q1, the current limiting resistor R3 is connected between the base of the transistor Q1 and the negative electrode of the electrolytic capacitor EC1. When the voltage of the external power supply is small, the amplification factor of the transistor Q1 is low, and the influence of the current limiting resistor R3 is not great. However, when the voltage of the external power supply increases, since the amplification factor of the transistor Q1 will increase, if there is no current limiting resistor R3 to control, the input current will increase sharply, which may cause damage to the transistor Q1. Therefore, by setting a current limiting resistor R3 of an appropriate size, the size of the input current can be limited to a certain extent, protecting the normal operation of the transistor Q1 and other components.

[0049] For example, in one embodiment, the enabling module 120 includes a current limiting resistor R3 and a transistor Q1; one end of the current limiting resistor R3 is respectively connected to the drain of the switching tube Q2 and the negative electrode of the electrolytic capacitor EC1, the other end of the current limiting resistor R3 is connected to the base of the transistor Q1, the collector of the transistor Q1 is connected to the enable terminal EN of the subsequent circuit, and the emitter of the transistor Q1 is grounded GND.

[0050] For example, in one embodiment, the transistor Q1 is used to be in the on state when the electrolytic capacitor EC1 is charged, the collector of the transistor Q1 is at a low level, and an enable signal in the low level state is output to the subsequent circuit of the communication device; the transistor Q1 is also used to be in the off state after the electrolytic capacitor EC1 is completely charged, the collector of the transistor Q1 is converted to a high level, and an enable signal in the high level state is output to the subsequent circuit of the communication device.

[0051] Example 2

[0052] The present application also relates to a communication device, including the soft start circuit as described in the above-mentioned embodiment 1.

[0053] Exemplarily, the slow start circuit is used for the power control circuit of the communication equipment, and is used to control the startup transient process of the power input end of the communication equipment at the moment of power-on, so as to prevent the instantaneous impact current from damaging the circuit and the communication equipment. The working principle of the slow start circuit is to use the switch tube as a switch at the power input end, and slowly boost the external power input through the filter capacitor, so that the communication equipment will not be subjected to excessive voltage and current impact during the startup process, thereby improving the reliability and stability of the communication equipment.

[0054] For example, in one implementation, the communication device further includes a power input terminal and a subsequent circuit respectively connected to two ends of the soft start circuit.

[0055] Exemplarily, the output end of the slow-start circuit can be directly connected to the rear-stage circuit and the power input end of the communication device to achieve control of the external power supply and alleviate the voltage and current impact when the communication device starts; the slow-start circuit can also be connected in series between the power input end and the rear-stage circuit of the communication device to play a buffering role; the slow-start circuit can also be connected in parallel between the power input end and the rear-stage circuit of the communication device to achieve dual protection of the external power supply and the communication device. Among them, the above-mentioned communication equipment can be various gateway devices and devices for communication such as routers and switches. The rear-stage circuit of the communication equipment refers to the back-end circuit parts such as signal distribution, driving and amplification, which can be a demodulation circuit, a driving circuit, an amplification circuit, etc.

[0056] In several embodiments provided in the present application, it should be understood that the disclosed apparatus and method can also be implemented in other ways. The apparatus embodiments described above are merely schematic, for example, the flowcharts and structure diagrams in the accompanying drawings show the possible architecture, functions and operations of the apparatus, method and computer program product according to multiple embodiments of the present application. In this regard, each box in the flowchart or block diagram can represent a module, a program segment or a part of a code, and a module, a program segment or a part of a code contains one or more executable instructions for implementing a specified logical function. It should also be noted that in an alternative implementation, the functions marked in the box can also occur in a different order from that marked in the accompanying drawings. For example, two consecutive boxes can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the structure diagram and / or the flow diagram, and the combination of boxes in the structure diagram and / or the flow diagram, can be implemented with a dedicated hardware-based system that performs a specified function or action, or can be implemented with a combination of dedicated hardware and computer instructions.

[0057] In addition, the functional modules or units in the various embodiments of the present application may be integrated together to form an independent part, or each module may exist separately, or two or more modules may be integrated to form an independent part.

[0058] If the function is implemented in the form of a software function module and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application can be essentially or partly embodied in the form of a software product that contributes to the prior art. The computer software product is stored in a storage medium, including several instructions for a computer device (which can be a smart phone, a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the various embodiments of the present application. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk and other media that can store program codes.

[0059] The above are only specific implementation methods of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be covered by the protection scope of the present application.

Claims

1. A slow start circuit, characterized in that: Including a slow start control module and an enabling module; The soft start control module is used to connect the external power supply and the power input terminal of the communication device, and when the external power supply is connected, changes the level signal output by the enabling module; The enabling module is used to control the power supply enabling of the subsequent power supply of the communication device according to the changed level signal, so as to delay the input of the external power supply into the subsequent circuit of the communication device.

2. The slow start circuit according to claim 1, characterized in that: The slow start control module comprises an energy storage unit, a filtering delay unit, a switch unit and a voltage dividing unit, wherein the energy storage unit and the voltage dividing unit are both connected to the external power supply, the energy storage unit is connected to the switch unit, the switch unit is connected to the filtering delay unit, and the filtering delay unit is connected to the voltage dividing unit; The energy storage unit is used to enter a charging state when connected to the external power supply, and is in an open circuit state after charging is completed, so that the enabling module outputs the level signal in a high level state when the energy storage unit is in the open circuit state; The filtering delay unit is used to filter out the interference signal of the slow start control module and extend the conduction time of the switch unit; The voltage dividing unit is used to divide the voltage of the external power supply to obtain a divided voltage; The switch unit is used to be turned on after receiving the divided voltage, so as to conduct the external power supply to the communication device.

3. The slow start circuit according to claim 2, characterized in that: The energy storage unit includes an electrolytic capacitor, a positive electrode of the electrolytic capacitor is connected to a power input terminal of the communication device, and a negative electrode of the electrolytic capacitor is connected to the switch unit.

4. The slow start circuit according to claim 2, characterized in that: The switch unit comprises a switch tube, a drain of the switch tube is connected to the electrolytic capacitor of the energy storage unit, and a source of the switch tube is grounded.

5. The slow start circuit according to claim 2, characterized in that: The voltage dividing unit includes a first voltage dividing resistor and a second voltage dividing resistor, one end of the first voltage dividing resistor is connected to the power input end of the communication device, the other end of the first voltage dividing resistor is connected to one end of the second voltage dividing resistor, and the other end of the second voltage dividing resistor is grounded.

6. The slow start circuit according to claim 4, characterized in that: The filtering delay unit includes a filtering capacitor, the filtering capacitor is connected in parallel to the gate and source of the switching tube, and the filtering capacitor is connected in parallel to the second voltage-dividing resistor of the voltage-dividing unit.

7. The slow start circuit according to claim 4, characterized in that: The enabling module includes a current limiting resistor and a triode; One end of the current limiting resistor is respectively connected to the drain of the switch tube and the negative electrode of the electrolytic capacitor, the other end of the current limiting resistor is connected to the base of the transistor, the collector of the transistor is connected to the enable end of the subsequent circuit, and the emitter of the transistor is grounded.

8. The slow start circuit according to claim 7, characterized in that: The transistor is used to be in a conducting state when the electrolytic capacitor is charged, the collector of the transistor is at a low level, and outputs an enable signal in a low level state to the subsequent circuit of the communication device; The transistor is also used to be in a cut-off state after the electrolytic capacitor is completely charged, and the collector of the transistor is converted to a high level to output an enable signal in a high level state to a subsequent circuit of the communication device.

9. A communication device, characterized in that: The invention comprises a slow start circuit as claimed in any one of claims 1 to 8.

10. The communication device according to claim 9, characterized in that The communication device also includes a power input terminal and a subsequent circuit respectively connected to two ends of the soft start circuit.

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