Power-on current limiting circuit

Abstract

The utility model provides a power-on current limiting circuit. The power-on current limiting circuit comprises a voltage stabilizing module; the voltage stabilizing module and the first switch control module are respectively connected with the power supply input end; the input end of the first delay control module is connected to the output end of the voltage stabilizing module, and the output end of the first delay control module is connected with the first switch control module; the input end of the constant-current charging module is connected with the input end of the power supply; the output end of the constant current charging module and the output end of the first switch control module are connected in parallel to the input end of the DC-DC conversion module; the input end of the second switch control module is connected with the output end of the DC-DC conversion module; and the input end of the second delay control module is connected with the output end of the DC-DC conversion module, and the output end of the second delay control module is connected with the second switch control module.

Description

Technical Field

[0001] This utility model relates to the field of electronic circuit technology, specifically to an on-current limiting circuit. Background Technology

[0002] With the rapid development of modern communication technologies, the application of communication equipment in various fields has become increasingly widespread and profound. From traditional telecommunications base stations to emerging Internet of Things (IoT) devices, and then to 5G and future 6G communication systems, the types and quantities of communication equipment are increasing dramatically. This trend has not only driven the progress of global information technology but also profoundly changed people's lifestyles and social operating models.

[0003] In related technologies, large transient currents are generated when equipment in a communication system is powered on. This is mainly due to the combined effect of factors such as the charging of the large-capacity capacitor at the power input terminal, the initial low impedance characteristics of the load, and the startup characteristics of the power module. The large transient current can cause the power supply voltage to drop instantly, which may cause the communication equipment to reset or become unstable, affecting communication quality and system reliability. In addition, excessive transient currents may also damage the power supply lines and the power module inside the equipment, shortening the service life of the equipment. Utility Model Content

[0004] In view of the above problems, this utility model provides a power-on current limiting circuit, the power-on current limiting circuit including: a device body;

[0005] Voltage regulator module;

[0006] The first switch control module is connected to the power input terminal, and the voltage regulator module and the first switch control module are respectively connected to the power input terminal.

[0007] A first delay control module, the input terminal of which is connected to the output terminal of the voltage regulator module, and the output terminal of which is connected to the first switch control module and used to control the on / off state of the first switch control module;

[0008] A constant current charging module, wherein the input terminal of the constant current charging module is connected to the power input terminal;

[0009] The output terminal of the constant current charging module and the output terminal of the first switch control module are connected in parallel to the input terminal of the DC-DC converter module.

[0010] The second switch control module has its input terminal connected to the output terminal of the DC-DC converter module;

[0011] The second delay control module has its input terminal connected to the output terminal of the DC-DC converter module, and its output terminal connected to the second switch control module and used to control the on / off state of the second switch control module.

[0012] In one embodiment, the power-on current limiting circuit further includes:

[0013] A linear voltage regulator module is provided, wherein the output terminal of the second switch control module is connected to the input terminal of the linear voltage regulator module, and the output terminal of the linear voltage regulator module is used to connect to the load.

[0014] In one embodiment, the second switch control module includes: a second P-MOS switch;

[0015] The gate of the second P-MOS switch is connected to the second delay control module and is used to receive the delay control signal. The source of the second P-MOS switch is connected to the output terminal of the DC-DC converter module, and the drain of the second P-MOS switch is connected to the input terminal of the linear regulator module.

[0016] In one embodiment, the linear regulator module employs a low-dropout linear regulator, the input of which is connected to the output of the second switch control module, and the output of which is used to connect to the load.

[0017] In one embodiment, the voltage regulator module includes: a Zener diode, a first voltage divider resistor, a second voltage divider resistor, and a Zener transistor;

[0018] The anode of the Zener diode is grounded, and the cathode of the Zener diode is connected to the power input terminal after being connected in series with the first voltage divider resistor and the second voltage divider resistor.

[0019] The collector of the Zener transistor is connected to the voltage divider node between the first voltage divider resistor and the second voltage divider resistor. The base of the Zener transistor is connected to the junction point between the cathode of the Zener diode and the first voltage divider resistor. The emitter of the Zener transistor is used to output a regulated voltage signal.

[0020] In one embodiment, the first delay control module includes: a first series resistor network, a first delay capacitor, and a first delay transistor;

[0021] The first end of the first series resistor network is connected to the output terminal of the voltage regulator module, and the second end of the first series resistor network is grounded through the first delay capacitor;

[0022] The base of the first delay transistor is connected to the middle voltage divider node of the first series resistor network, the emitter of the first delay transistor is directly connected to the output terminal of the voltage regulator module, and the collector of the first delay transistor is used to output a delay control signal.

[0023] In one embodiment, the first switch control module includes: a cascaded drive transistor group and a first P-MOS switch;

[0024] The cascaded driving transistor group includes at least a front-stage transistor and a final-stage transistor connected in series. The base of the front-stage transistor is used to receive a delay control signal, and the output terminal of the final-stage transistor is connected to the gate of the first P-MOS switch.

[0025] The source of the first P-MOS switch is connected to the power input terminal, and the drain of the first P-MOS switch is output to the DC-DC converter module.

[0026] In one embodiment, the constant current charging module includes: a constant current transistor, a reference voltage regulator, and a current setting resistor network;

[0027] The emitter of the constant current transistor is connected to the power input terminal through the current setting resistor network, the base of the constant current transistor is connected to the reference voltage established by the reference voltage regulator, and the collector of the constant current transistor is used to output a constant current charging current.

[0028] In one embodiment, the DC-DC converter module includes: a buck controller chip, an input filter capacitor, and an output filter capacitor;

[0029] The input filter capacitor is connected in parallel to the input terminal of the buck controller chip, and the output filter capacitor is connected in parallel to the output terminal of the buck controller chip.

[0030] In one embodiment, the second delay control module includes: a second series resistor network, a second delay capacitor, and a second delay transistor;

[0031] The first end of the second series resistor network is connected to the output terminal of the DC-DC converter module, and the second end of the second series resistor network is grounded through the second delay capacitor;

[0032] The base of the second delay transistor is connected to the middle voltage divider node of the second series resistor network, the emitter of the second delay transistor is directly connected to the output terminal of the DC-DC converter module, and the collector of the second delay transistor is used to output a delay control signal.

[0033] The above-described one or more technical solutions in the embodiments of this application have at least one or more of the following technical effects:

[0034] In this embodiment of the invention, a power-on current limiting circuit is provided. During the initial power-on phase, the power supply voltage is first connected to the circuit. After being regulated by a voltage regulator module, a stable voltage is output to the first delay control module. Due to the control function of the first delay control module, the first switch control module is in the off state, and the power supply voltage cannot directly supply power to subsequent circuits through the first switch control module. At this time, the power supply voltage charges the DC-DC converter module with a constant current through a constant current charging module. The function of the constant current charging module is to limit the charging current, preventing transient large currents from impacting the power lines and equipment. This constant current charging method effectively controls the current during power-on, preventing voltage drops and equipment restarts, thereby improving the stability and reliability of the system. During the constant current charging process, the charged voltage is converted by the DC-DC converter module and a voltage signal is provided to the second delay control module. Upon receiving the voltage signal, the second delay control module starts timing and controls the second switch control module to remain in the off state, preventing the load from receiving power. When the charging time of the first and second delay control modules reaches a preset value, the first delay control module controls the first switch control module to turn on, allowing the power supply voltage to be directly supplied to the DC-DC converter module through the first switch control module. Simultaneously, the second delay control module controls the second switch control module to turn on, allowing the voltage output from the DC-DC converter module to be directly supplied to the load. At this time, the constant current charging module no longer charges the DC-DC converter module and remains in standby mode, waiting for the next power-on process. Through this design, the circuit effectively limits transient large currents during power-on through constant current charging and delay control, avoiding voltage drops and device restarts, ensuring that each part of the circuit gradually stabilizes during power-on, and avoiding voltage fluctuations caused by excessive instantaneous load, thereby improving the stability and reliability of the communication equipment. This power-on current limiting circuit can be widely used in various communication devices to ensure stable operation of the equipment during power-on.

[0035] The above description is merely an overview of the technical solution of this utility model. In order to better understand the technical means of this utility model and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this utility model more obvious and understandable, specific embodiments of this utility model are given below. Attached Figure Description

[0036] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0037] Figure 1 This is a schematic diagram of the power-on current limiting circuit module in an embodiment of this utility model;

[0038] Figure 2 This is a schematic diagram of the power-on current limiting circuit in an embodiment of this utility model.

[0039] Explanation of reference numerals in the attached figures: 100, voltage regulator module; 200, first switch control module; 300, power input terminal; 400, first delay control module; 500, constant current charging module; 600, DC-DC converter module; 700, second switch control module; 800, second delay control module; 900, linear voltage regulator module. Detailed Implementation

[0040] The overall concept of the technical solution provided by this utility model is as follows:

[0041] Please see Figure 1 The power-on current limiting circuit includes:

[0042] Voltage regulator module 100; After the power supply voltage is connected to the circuit, the voltage regulator module 100 is used to regulate the power supply voltage to ensure that a stable voltage is provided to the subsequent circuit and to avoid voltage fluctuations from affecting the subsequent circuit.

[0043] The first switch control module 200 and the voltage regulator module 100 are respectively connected to the power input terminal 300; the first switch control module 200 is used to control the on and off of the circuit;

[0044] The first delay control module 400 has its input terminal connected to the output terminal of the voltage regulator module 100, and its output terminal connected to the first switch control module 200 and used to control the on / off state of the first switch control module 200. The first delay control module 400 is used to control the first switch control module 200 to be on and off within a preset time. For example, at the initial stage of power-on, the first delay control module 400 controls the first switch control module 200 to be in the off state, and after the preset time, controls it to be on.

[0045] The constant current charging module 500 is connected to the power input terminal 300. The constant current charging module 500 is used to charge the DC-DC converter module 600 with a constant current during the initial power-on period, limiting the charging current and avoiding the impact of transient large current on the power lines and equipment.

[0046] The output terminals of the DC-DC converter module 600, the constant current charging module 500, and the first switch control module 200 are connected in parallel to the input terminal of the DC-DC converter module 600; the DC-DC converter module 600 is used to perform voltage conversion and provide a voltage signal to the second delay control module 800.

[0047] The second switch control module 700 has its input terminal connected to the output terminal of the DC-DC converter module 600; the second switch control module 700 is used to control the on / off state of the circuit.

[0048] A second delay control module 800 has its input connected to the output of the DC-DC converter module 600, and its output connected to the second switch control module 700 to control the on / off state of the second switch control module 700. The second delay control module 800 controls the on / off state of the second switch control module 700. For example, during the initial power-on phase, after receiving a voltage signal, it starts timing and controls the second switch control module 700 to be in the off state. After a preset time, it controls the second switch control module 700 to be turned on, allowing the voltage output from the DC-DC converter module 600 to be directly supplied to the load.

[0049] Specifically, during the initial power-on phase, the power supply voltage is first connected to the circuit. After being regulated by the voltage regulator module 100, a stable voltage is output to the first delay control module 400. Due to the control function of the first delay control module 400, the first switch control module 200 is in the off state, and the power supply voltage cannot directly supply power to subsequent circuits through the first switch control module 200. At this time, the power supply voltage charges the DC-DC converter module 600 with a constant current through the constant current charging module 500. The function of the constant current charging module 500 is to limit the charging current and avoid transient large currents from impacting the power lines and equipment. Through this constant current charging method, the current during power-on can be effectively controlled to avoid voltage drops and equipment restarts, thereby improving the stability and reliability of the system. During the constant current charging process, the charged voltage is converted by the DC-DC converter module 600 and a voltage signal is provided to the second delay control module 800. After receiving the voltage signal, the second delay control module 800 starts timing and controls the second switch control module 700 to remain in the off state, preventing the load from receiving power. When the charging time of the first delay control module 400 and the second delay control module 800 reaches the preset value, the first delay control module 400 controls the first switch control module 200 to be turned on, so that the power supply voltage is directly supplied to the DC-DC converter module 600 through the first switch control module 200. Simultaneously, the second delay control module 800 controls the second switch control module 700 to turn on, allowing the voltage output from the DC-DC converter module 600 to be directly supplied to the load. At this time, the constant current charging module 500 no longer charges the DC-DC converter module 600 and remains in standby mode, waiting for the next power-on process. Through this design, the circuit effectively limits transient large currents during power-on by using constant current charging and delay control, avoiding voltage drops and device restarts. This ensures that each part of the circuit gradually stabilizes during power-on, avoiding voltage fluctuations caused by excessive instantaneous load, thereby improving the stability and reliability of the communication equipment. This power-on current limiting circuit can be widely used in various communication devices to ensure stable operation of the equipment during power-on.

[0050] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0051] Please see Figure 1 The power-on current limiting circuit also includes:

[0052] The output terminal of the second switch control module 700 is connected to the input terminal of the linear voltage regulator module 900, and the output terminal of the linear voltage regulator module 900 is used to connect to the load. The linear voltage regulator module 900 is used to further regulate the input voltage, ensuring that the voltage output to the load is more stable and accurate. By introducing the linear voltage regulator module 900, the stability and reliability of the system are further improved.

[0053] Furthermore, the second switch control module 700 includes: a second P-MOS switch;

[0054] The gate of the second P-MOS switch is connected to the second delay control module 800 and is used to receive delay control signals. The source of the second P-MOS switch is connected to the output terminal of the DC-DC converter module 600, and the drain of the second P-MOS switch is connected to the input terminal of the linear regulator module 900. For details, please refer to [link to relevant documentation]. Figure 2 The second P-MOS switch includes MOS transistor Q50A. MOS transistor Q50A acts as a switching element to control the on / off state of current. The gate of MOS transistor Q50A is connected to the second delay control module 800 to receive the delay control signal sent by the second delay control module 800. The high and low levels of the delay control signal determine the on and off states of MOS transistor Q50A. The source of MOS transistor Q50A is connected to the output terminal of DC-DC converter module 600 as the current input terminal. The drain of MOS transistor Q50A is connected to the input terminal of linear regulator module 900 as the current output terminal.

[0055] For further details, please refer to Figure 2 The linear regulator module 900 employs a low-dropout linear regulator VR1. The input of VR1 is connected to the output of the second switching control module 700, while its output is used to connect to the load. Specifically, VR1 provides a stable output voltage, exhibiting low dropout characteristics and enabling normal operation even when the input voltage is slightly higher than the output voltage. VR1's input is connected to the output of the second switching control module 700, specifically the drain of the MOSFET Q50A, receiving the output voltage from the DC-DC converter module 600. VR1's output is connected to the load, and the output voltage, after being regulated by VR1, provides a stable power supply voltage to the load, ensuring voltage stability and accuracy.

[0056] For further details, please refer to Figure 2 The voltage regulator module 100 includes: a Zener diode D112, a first voltage divider resistor R116, a second voltage divider resistor R115, and a Zener transistor Q107.

[0057] The anode of the Zener diode D112 is grounded, and the cathode of the Zener diode D112 is connected in series with the first voltage divider resistor R116 and the second voltage divider resistor R115 and then connected to the power input terminal 300.

[0058] The collector of the Zener transistor Q107 is connected to the voltage divider node between the first voltage divider resistor R116 and the second voltage divider resistor R115. The base of the Zener transistor Q107 is connected to the junction of the cathode of the Zener diode D112 and the first voltage divider resistor R116. The emitter of the Zener transistor Q107 is used to output a regulated voltage signal.

[0059] Specifically, the Zener diode D112 operates in reverse breakdown mode, providing a stable reference voltage. For example, if the Zener diode D112 has a Zener voltage of 5.1V, then under normal operating conditions, its cathode voltage will be stable at 5.1V. The first voltage divider resistor R116 and the second voltage divider resistor R115 form a voltage divider network, which divides the power input voltage and provides it to the collector of the Zener transistor Q107. The Zener transistor Q107 operates in the amplification region, and its base voltage is provided by the Zener diode D112. When the power input voltage changes, the voltage at the voltage divider node also changes. The Zener transistor Q107 maintains the stability of the output voltage by adjusting its own conduction level. For example, if the input voltage increases, the voltage at the voltage divider node will also increase, and the Zener transistor Q107 will increase its conduction level to decrease the output voltage; conversely, the emitter of the Zener transistor Q107 outputs a regulated signal, which is provided to the subsequent circuits. Due to the regulating effect of the Zener transistor Q107, the output voltage can remain stable and is not affected by fluctuations in the power input voltage.

[0060] For further details, please refer to Figure 2 The first delay control module 400 includes: a first series resistor network, a first delay capacitor C121 and a first delay transistor Q108;

[0061] The first end of the first series resistor network is connected to the output terminal of the voltage regulator module 100, and the second end of the first series resistor network is grounded through the first delay capacitor C121.

[0062] The base of the first delay transistor Q108 is connected to the middle voltage divider node of the first series resistor network, the emitter of the first delay transistor Q108 is directly connected to the output terminal of the voltage regulator module 100, and the collector of the first delay transistor Q108 is used to output the delay control signal.

[0063] Specifically, the first series resistor network consists of multiple resistors connected in series, used for voltage division and current limiting, such as... Figure 2As shown, the first series resistor network can be formed by resistors R119 and R121 connected in series. The first delay capacitor C121 is used to control the delay time, and the first delay transistor Q108 is used to output the delay control signal. At the initial power-on stage, the power supply voltage is connected to the circuit. After being regulated by the voltage regulator module 100, a stable voltage is output to the first series resistor network. The first series resistor network and the first delay capacitor C121 form an RC delay circuit. When the power supply voltage is connected, the first delay capacitor C121 begins to charge, and the charging current flows through... The first series resistor network flows to the first delay capacitor C121. Due to the presence of the resistor, the charging process is gradual, and the voltage gradually increases. The base voltage of the first delay transistor Q108 is provided by the intermediate voltage divider node of the first series resistor network (such as the node between resistor R119 and resistor R121). When the first delay capacitor C121 is charged to a certain voltage, the voltage of the intermediate voltage divider node reaches the conduction threshold of the first delay transistor Q108, and the first delay transistor Q108 starts to conduct, and the collector outputs a delay control signal.

[0064] For further details, please refer to Figure 2 The first switch control module 200 includes: a cascaded drive transistor group and a first P-MOS switch Q110;

[0065] The cascaded drive transistor group includes at least a front-stage transistor Q112 and a final-stage transistor Q111 connected in series. The base of the front-stage transistor Q112 is used to receive a delay control signal, and the output of the final-stage transistor Q111 is connected to the gate of the first P-MOS switch Q110.

[0066] The source of the first P-MOS switch Q110 is connected to the power input terminal 300, and the drain of the first P-MOS switch Q110 is output to the DC-DC converter module 600.

[0067] Specifically, the cascaded drive transistor group consists of at least two transistors connected in series, such as the front-stage transistor Q112 and the final-stage transistor Q111 connected in series, used to amplify and control the delay control signal; the first P-MOS switch Q110 acts as the main switching element, used to control the on / off state of the power supply voltage; for example, at the initial stage of power-on, the first delay control module 400 outputs a delay control signal, such as a high-level output, which controls the front-stage transistor Q112 to conduct, and the front-stage transistor Q112 controls the final-stage transistor Q111 to be cut off, thus the final-stage transistor Q111... When the first P-MOS switch Q110 is turned off, the first delay control module 400 starts timing. The state of the cascaded drive transistor group and the first P-MOS switch Q110 remains unchanged. When the delay time reaches the preset value, the first delay control module 400 outputs a low-level delay control signal. At this time, the front-stage transistor Q112 is turned off, the final-stage transistor Q111 is turned on, and the first P-MOS switch Q110 is also turned on. The power supply voltage is supplied to the DC-DC converter module 600 through the first P-MOS switch Q110.

[0068] For further details, please refer to Figure 2 The constant current charging module 500 includes: a constant current transistor Q109, a reference voltage regulator D116, and a current setting resistor network;

[0069] The emitter of the constant current transistor Q109 is connected to the power input terminal 300 through a current setting resistor network. The base of the constant current transistor Q109 is connected to the reference voltage established by the reference voltage regulator D116. The collector of the constant current transistor Q109 is used to output a constant current charging current.

[0070] Specifically, the constant current transistor Q109 is used to output a constant charging current, and the reference voltage regulator D116 is used to provide a stable reference voltage. The reference voltage regulator D116 can be a Zener diode. The current setting resistor network consists of multiple resistors used to set the constant current value. For example, the current setting resistor network can be composed of parallel resistors R123 and R124. The reference voltage regulator D116 provides a stable reference voltage, such as 5.1V. This reference voltage is used to set the operating point of the constant current transistor Q109. The constant current transistor Q109 operates in the amplification region, and its collector current is mainly determined by the base voltage and the emitter resistor. The base voltage is provided by the reference voltage regulator D116, and the emitter resistor is determined by the current setting resistor network. The constant current transistor Q109 outputs a constant charging current to charge the DC-DC converter module 600. Because the charging current is constant, it can effectively limit transient large currents and avoid impacting the power supply line and equipment.

[0071] For further details, please refer to Figure 2The DC-DC converter module 600 includes: a buck controller chip U1, an input filter capacitor C106, and an output filter capacitor C7;

[0072] The input filter capacitor C106 is connected in parallel to the input terminal of the buck controller chip U1, and the output filter capacitor C7 is connected in parallel to the output terminal of the buck controller chip U1.

[0073] Specifically, the buck controller chip U1 serves as the core control element, realizing voltage conversion and regulation functions. The input filter capacitor C106 and the output filter capacitor C7 are used to filter out noise and ripple from the input power supply and to filter out noise and ripple from the output voltage, respectively.

[0074] For further details, please refer to Figure 2 The second delay control module 800 includes: a second series resistor network, a second delay capacitor C52, and a second delay transistor Q53;

[0075] The first end of the second series resistor network is connected to the output of the DC-DC converter module 600, and the second end of the second series resistor network is grounded through the second delay capacitor C52.

[0076] The base of the second delay transistor Q53 is connected to the middle voltage divider node of the second series resistor network, the emitter of the second delay transistor Q53 is directly connected to the output terminal of the DC-DC converter module 600, and the collector of the second delay transistor Q53 is used to output the delay control signal.

[0077] Specifically, the second series resistor network consists of multiple resistors (such as resistors R57 and R58) connected in series, used for voltage division and current limiting. The second delay capacitor C52 is used to control the delay time, and the second delay transistor Q53 is used to output the delay control signal. At the initial power-on stage, the DC-DC converter module 600 starts working, and the output voltage gradually rises. The second series resistor network and the second delay capacitor C52 form an RC delay circuit. When the output voltage of the DC-DC converter module 600 rises, the second delay capacitor C52 begins to charge. The charging current flows through the second series resistor network to the second delay capacitor C52. Due to the resistance, the charging... The process is gradual, with the voltage gradually increasing. The base voltage of the second delay transistor Q53 is provided by the intermediate voltage divider node of the second series resistor network. When the second delay capacitor C52 is charged to a certain voltage, the voltage of the intermediate voltage divider node reaches the conduction threshold of the second delay transistor Q53, and the second delay transistor Q53 begins to conduct. The collector outputs a delay control signal, which controls the on / off state of the second switch control module 700. For example, when the delay control signal is high, the second switch control module 700 is off; when the delay control signal is low, the second switch control module 700 is on.

[0078] Although preferred embodiments of the present invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of the present invention.

[0079] Obviously, those skilled in the art can make various modifications and variations to the embodiments of this utility model without departing from the spirit and scope of the embodiments of this utility model. Therefore, if these modifications and variations to the embodiments of this utility model fall within the scope of the claims of this utility model and their equivalents, then this utility model also intends to include these modifications and variations.

Claims

1. A current limiting circuit, characterized in that, include: Voltage regulator module; The first switch control module is connected to the power input terminal, and the voltage regulator module and the first switch control module are respectively connected to the power input terminal. A first delay control module, the input terminal of which is connected to the output terminal of the voltage regulator module, and the output terminal of which is connected to the first switch control module and used to control the on / off state of the first switch control module; A constant current charging module, wherein the input terminal of the constant current charging module is connected to the power input terminal; The output terminal of the constant current charging module and the output terminal of the first switch control module are connected in parallel to the input terminal of the DC-DC converter module. The second switch control module has its input terminal connected to the output terminal of the DC-DC converter module; The second delay control module has its input terminal connected to the output terminal of the DC-DC converter module, and its output terminal connected to the second switch control module and used to control the on / off state of the second switch control module.

2. The power-on current limiting circuit according to claim 1, characterized in that, Also includes: A linear voltage regulator module is provided, wherein the output terminal of the second switch control module is connected to the input terminal of the linear voltage regulator module, and the output terminal of the linear voltage regulator module is used to connect to the load.

3. The power-on current limiting circuit according to claim 2, characterized in that, The second switch control module includes: a second P-MOS switch; The gate of the second P-MOS switch is connected to the second delay control module and is used to receive the delay control signal. The source of the second P-MOS switch is connected to the output terminal of the DC-DC converter module, and the drain of the second P-MOS switch is connected to the input terminal of the linear regulator module.

4. The power-on current limiting circuit according to claim 2, characterized in that, The linear voltage regulator module uses a low-dropout linear regulator. The input terminal of the low-dropout linear regulator is connected to the output terminal of the second switch control module, and the output terminal of the low-dropout linear regulator is used to connect to the load.

5. The power-on current limiting circuit according to claim 1, characterized in that, The voltage regulator module includes: a Zener diode, a first voltage divider resistor, a second voltage divider resistor, and a Zener transistor; The anode of the Zener diode is grounded, and the cathode of the Zener diode is connected to the power input terminal after being connected in series with the first voltage divider resistor and the second voltage divider resistor. The collector of the Zener transistor is connected to the voltage divider node between the first voltage divider resistor and the second voltage divider resistor. The base of the Zener transistor is connected to the junction point between the cathode of the Zener diode and the first voltage divider resistor. The emitter of the Zener transistor is used to output a regulated voltage signal.

6. The power-on current limiting circuit according to claim 1, characterized in that, The first delay control module includes: a first series resistor network, a first delay capacitor, and a first delay transistor; The first end of the first series resistor network is connected to the output terminal of the voltage regulator module, and the second end of the first series resistor network is grounded through the first delay capacitor; The base of the first delay transistor is connected to the middle voltage divider node of the first series resistor network, the emitter of the first delay transistor is directly connected to the output terminal of the voltage regulator module, and the collector of the first delay transistor is used to output a delay control signal.

7. The power-on current limiting circuit according to claim 1, characterized in that, The first switch control module includes: a cascaded drive transistor group and a first P-MOS switch; The cascaded driving transistor group includes at least a front-stage transistor and a final-stage transistor connected in series. The base of the front-stage transistor is used to receive a delay control signal, and the output terminal of the final-stage transistor is connected to the gate of the first P-MOS switch. The source of the first P-MOS switch is connected to the power input terminal, and the drain of the first P-MOS switch is output to the DC-DC converter module.

8. The power-on current limiting circuit according to claim 1, characterized in that, The constant current charging module includes: a constant current transistor, a reference voltage regulator, and a current setting resistor network; The emitter of the constant current transistor is connected to the power input terminal through the current setting resistor network, the base of the constant current transistor is connected to the reference voltage established by the reference voltage regulator, and the collector of the constant current transistor is used to output a constant current charging current.

9. The power-on current limiting circuit according to claim 1, characterized in that, The DC-DC converter module includes: a buck controller chip, an input filter capacitor, and an output filter capacitor; The input filter capacitor is connected in parallel to the input terminal of the buck controller chip, and the output filter capacitor is connected in parallel to the output terminal of the buck controller chip.

10. The power-on current limiting circuit according to claim 1, characterized in that, The second delay control module includes: a second series resistor network, a second delay capacitor, and a second delay transistor; The first end of the second series resistor network is connected to the output terminal of the DC-DC converter module, and the second end of the second series resistor network is grounded through the second delay capacitor; The base of the second delay transistor is connected to the middle voltage divider node of the second series resistor network, the emitter of the second delay transistor is directly connected to the output terminal of the DC-DC converter module, and the collector of the second delay transistor is used to output a delay control signal.

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