A DC inrush current suppression circuit with automatic adjustment

Abstract

This utility model discloses an automatically adjustable DC inrush current suppression circuit, relating to the field of power electronics technology. The suppression circuit includes: an auxiliary module for connecting to a power supply and controlling the consistency during charging to prevent circuit damage caused by reverse connection; an RC network module for receiving circuit signals and dynamically adjusting the charging time constant based on the circuit signals to control the opening of a switch; a switch for limiting inrush current and ensuring normal power supply; a current detection module for detecting inrush current, converting it into a voltage signal, and providing feedback on the current level; the output terminal of the auxiliary module is connected to the input terminal of the RC network module, the output terminal of the RC network module is connected to the input terminal of the switch, and the output terminal of the switch is connected to the input terminal of the current detection module. This utility model ensures that the voltage of the MOSFET Q1 does not fluctuate due to changes in load current when it is turned on.

Description

Technical Field

[0001] This utility model relates to the field of power electronics technology, and more specifically, to a DC inrush current suppression circuit with automatic adjustment. Background Technology

[0002] Currently, most control systems use a large number of filters and energy storage capacitors. When the system starts up, it will generate inrush current. The instantaneous current provided by the power supply system needs to be several times higher than the rated current to meet the system requirements. Therefore, it is necessary to design an inrush current suppression circuit at the power input port. However, the inrush current suppression circuit will slow down the system startup time, especially for systems with large load capacitive reactance changes, making it difficult to control the system startup time.

[0003] Currently, commonly used inrush current suppression circuits have relatively simple functions, only suppressing inrush current. They cannot adjust the start-up time according to the load current, nor do they have modularity. The circuit parameters need to be adjusted in the system design to adapt to the balance between inrush current and start-up time during the start-up of the control system. In the process of control system development, there is a need for a standardized and modular circuit module to meet the needs of different control systems, thereby shortening the system development cycle and improving system performance.

[0004] The circuit modules in the existing technology have a fixed time constant, which makes them unable to adapt to changes in capacitive loads. They require manual parameter adjustment, have thermal inertia issues, require high intervals between repeated starts, and have limited mechanical contact lifespan.

[0005] No effective solutions have yet been proposed to address the problems in the relevant technologies. Utility Model Content

[0006] In view of the problems in the related technologies, this utility model proposes a DC inrush current suppression circuit with automatic adjustment to overcome the above-mentioned technical problems existing in the existing related technologies.

[0007] Therefore, the specific technical solution adopted by this utility model is as follows:

[0008] A DC inrush current suppression circuit with automatic adjustment, the suppression circuit comprising:

[0009] The auxiliary module is used to connect to the power supply and control the consistency during the charging process to prevent circuit damage caused by reverse power connection.

[0010] An RC network module is used to receive circuit signals and dynamically adjust the charging time constant according to the circuit signals to control the opening of the switch.

[0011] A switch is used to limit inrush current and ensure normal power supply.

[0012] The current detection module is used to detect inrush current and convert it into a voltage signal, providing feedback on the current level.

[0013] The output of the auxiliary module is connected to the input of the RC network module, the output of the RC network module is connected to the input of the switch, and the output of the switch is connected to the input of the current detection module.

[0014] Preferably, the auxiliary module includes a reverse polarity protection diode D1, an isolation diode D2, a gate protection Zener diode D3, resistors R3 and R2, capacitors C2 and C4; one end of the reverse polarity protection diode D1 is connected to one end of the RC network module and one end of the isolation diode D2, the other end of the isolation diode D2 is connected to one end of the capacitor C4 and one end of the current detection module, and the other end of the capacitor C4 is connected to one end of the switch; one end of the resistor R2 is connected to one end of the RC network module, one end of the gate protection Zener diode D3 and one end of the resistor R3, the other end of the resistor R2 is connected to the other end of the RC network module, the other end of the gate protection Zener diode D3 and one end of the capacitor C2, and the other end of the capacitor C2 is connected to the other end of the resistor R3 and one end of the switch.

[0015] Preferably, the reverse connection protection diode D1 is used to prevent the circuit from being damaged by reverse power connection, the isolation diode D2 is used to prevent the load-side capacitor C4 from affecting the charging consistency of the RC network module, the gate protection Zener diode D3 is used to prevent the switch from being over-voltaged and broken down, and the capacitor C2 and resistor R3 are used to stabilize the switch drive signal.

[0016] Preferably, the RC network module includes a resistor R1 and a capacitor C1; one end of the resistor R1 is connected to one end of the reverse polarity protection diode D1 and one end of the isolation diode D2, respectively; the other end of the resistor R1 is connected to one end of the capacitor C1, one end of the resistor R2 and one end of the resistor R3, respectively; the other end of the capacitor C1 is connected to the other end of the resistor R2, the other end of the capacitor C2 and one end of the switch, respectively.

[0017] Preferably, the switch is connected in series at the negative line of the circuit and presents high impedance when the gate voltage does not reach the threshold, limiting the inrush current. After being fully turned on, the impedance drops to the minimum to ensure normal power supply.

[0018] Preferably, the switch is a field-effect transistor Q1, and the source of the field-effect transistor Q1 is connected to one end of capacitor C2, one end of gate protection Zener diode D3, one end of resistor R2 and one end of capacitor C1, respectively. The gate of the field-effect transistor Q1 is connected to one end of resistor R3 and the other end of capacitor C2, respectively. The drain of the field-effect transistor Q1 is connected to one end of capacitor C4.

[0019] Preferably, the current detection module is connected in series with the sampling resistor R5 of the output positive line to detect the inrush current and convert it into a voltage signal, which is then output to the control circuit of the RC network module and the current level is fed back.

[0020] The beneficial effects of this utility model are as follows:

[0021] 1. This utility model automatically controls the RC parameters of the surge suppression circuit based on the starting current, thereby adjusting the starting time. It also designs a current detection circuit to detect the system current and feeds it back to the starting control circuit. The control circuit adjusts the RC time constant according to the system current level to control the starting time of the field-effect transistor. At the same time, the reverse connection protection diode D1 and the isolation diode D2 can ensure the unidirectionality of the power supply current and ensure the consistency of the RC time constant during cold and hot starts, thereby ensuring the consistency of the system starting time. Furthermore, the Zener diode D3 is set to ensure the minimum turn-on voltage of the field-effect transistor Q1. The resistor R3 and the capacitor C2 are used to ensure the steady-state turn-on and turn-off of the field-effect transistor Q1.

[0022] 2. This utility model can ensure the consistency of RC parameters during cold and hot starts of the system by designing anti-reverse connection diode D1 and isolation diode D2. At the same time, based on the RC network and control circuit, the turn-on time of field-effect transistor Q1 is automatically adjusted. Furthermore, field-effect transistor Q1 is designed on the negative terminal of the circuit to ensure that the voltage of field-effect transistor Q1 will not fluctuate due to changes in load current when it is turned on. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a block diagram of a DC inrush current suppression circuit with automatic adjustment according to an embodiment of the present utility model;

[0025] Figure 2 This is a schematic diagram of a DC inrush current suppression circuit with automatic adjustment according to an embodiment of the present invention.

[0026] In the picture:

[0027] 1. Auxiliary module; 2. RC network module; 3. Switch; 4. Current detection module. Detailed Implementation

[0028] To further illustrate the various embodiments, the present invention provides accompanying drawings, which are part of the disclosure of the present invention. These drawings are mainly used to illustrate the embodiments and can be used in conjunction with the relevant descriptions in the specification to explain the operating principles of the embodiments. With reference to these drawings, those skilled in the art should be able to understand other possible implementation methods and the advantages of the present invention.

[0029] According to an embodiment of the present invention, a DC inrush current suppression circuit with automatic adjustment is provided.

[0030] The present invention will now be further described in conjunction with the accompanying drawings and specific embodiments, such as... Figure 1 As shown, according to an embodiment of the present invention, a DC inrush current suppression circuit with automatic adjustment is provided, the suppression circuit comprising:

[0031] Auxiliary module 1 is used to connect to the power supply and control the consistency during the charging process to prevent circuit damage caused by reverse power connection.

[0032] RC network module 2 is used to receive circuit signals and dynamically adjust the charging time constant according to the circuit signals to control the opening of switch 3;

[0033] Switch 3 is used to limit inrush current and ensure normal power supply;

[0034] Current detection module 4 is used to detect inrush current and convert it into voltage signal, and provide feedback on current level;

[0035] The output of auxiliary module 1 is connected to the input of RC network module 2, the output of RC network module 2 is connected to the input of switch 3, and the output of switch 3 is connected to the input of current detection module 4.

[0036] like Figure 2 As shown, in one embodiment, the auxiliary module 1 includes a reverse connection protection diode D1, an isolation diode D2, a gate protection Zener diode D3, resistors R3 and R2, capacitors C2 and C4; one end of the reverse connection protection diode D1 is connected to one end of the RC network module 2 and one end of the isolation diode D2, the other end of the isolation diode D2 is connected to one end of the capacitor C4 and one end of the current detection module 4, and the other end of the capacitor C4 is connected to one end of the switch 3; one end of the resistor R2 is connected to one end of the RC network module 2, one end of the gate protection Zener diode D3 and one end of the resistor R3, the other end of the resistor R2 is connected to the other end of the RC network module 2, the other end of the gate protection Zener diode D3 and one end of the capacitor C2, and the other end of the capacitor C2 is connected to the other end of the resistor R3 and one end of the switch 3.

[0037] like Figure 2As shown, in one embodiment, the RC network module 2 includes a resistor R1 and a capacitor C1; one end of the resistor R1 is connected to one end of the reverse connection protection diode D1 and one end of the isolation diode D2, respectively; the other end of the resistor R1 is connected to one end of the capacitor C1, one end of the resistor R2 and one end of the resistor R3, respectively; the other end of the capacitor C1 is connected to the other end of the resistor R2, the other end of the capacitor C2 and one end of the switch 3, respectively.

[0038] like Figure 2 As shown, in one embodiment, switch 3 is a field-effect transistor Q1, and the source of field-effect transistor Q1 is connected to one end of capacitor C2, one end of gate protection Zener diode D3, one end of resistor R2 and one end of capacitor C1, respectively. The gate of field-effect transistor Q1 is connected to one end of resistor R3 and the other end of capacitor C2, respectively. The drain of field-effect transistor Q1 is connected to one end of capacitor C4.

[0039] like Figure 2 As shown in the diagram, IN+ / IN- represent the DC power input terminal; OUT+ / OUT- represent the DC power output terminal; D1 represents the reverse polarity protection diode; R1 / C1 network represents the adjustable RC network, the control circuit; Q1 represents the N-channel MOSFET; R5 represents the current sampling resistor; D2 represents the isolation diode; D3 represents the gate protection Zener diode; R3 / C2 represents the MOSFET gate filter circuit; and C4 represents the DC power filter capacitor.

[0040] To facilitate understanding of the above-mentioned technical solutions of this utility model, the working principle or operation method of this utility model in actual process will be described in detail below.

[0041] In practical applications, the DC inrush current suppression circuit with automatic adjustment proposed in this embodiment includes a current detection circuit connected in series on the positive output line of the circuit to test the power supply current of the circuit. The current detection module 4 is also connected to the RC parameter control circuit to feed back the current level to the RC parameter control circuit. The RC parameter control circuit is connected to the power input circuit and the switching MOSFET control stage. It adjusts the RC parameters according to the load current level and controls the turn-on time of the switching MOSFET Q1. The reverse connection protection diode D1 and the isolation diode D2 are used to prevent the energy storage C4 in the circuit from affecting the RC parameters and to ensure the consistency of the RC parameter circuit in cold start and hot start. The switching MOSFET Q1 is connected in series on the negative line of the circuit to control the circuit start-up current and start-up time.

[0042] The current detection module 4 is connected in series with the sampling resistor R5 on the positive output line (IN+). It detects the inrush current and converts it into a voltage signal, which is output to the RC parameter control circuit to provide feedback on the current level. The RC network module 3 is composed of resistor R1 and capacitor C1. It receives the current detection signal and controls the dynamic adjustment of the charging time constant, controls the turn-on delay of MOSFET Q1 in switch 3, and adjusts its on-resistance. MOSFET Q1 is connected in series on the negative circuit line (IN-). When the gate voltage does not reach the threshold, it presents a high impedance to limit the inrush current. After it is fully turned on, the impedance drops to the minimum to ensure normal power supply. In the auxiliary module 1, the reverse connection protection diode D1 is used to prevent the circuit from being damaged by reverse connection of the power supply. The isolation diode D2 is used to prevent the load-side capacitor C4 from affecting the charging consistency of the RC network. The protection turn-on protection circuit D3 is used to prevent the gate overvoltage breakdown. The filter circuit (R3, C2) is used to stabilize the gate drive signal of Q1.

[0043] IN+ and IN- are the power input terminals. The input power is connected to the RC network through the anti-reverse diode D1. The power supply charges capacitor C1 through resistor R1. When the charging voltage on capacitor C1 reaches the turn-on threshold of MOSFET Q1, MOSFET Q1 is turned on through resistor R3. During the charging of capacitor C1, MOSFET Q1 is not fully turned on, and the impedance between the source and drain of MOSFET Q1 is relatively large, thereby limiting the input inrush current. When MOSFET Q1 is turned on, the impedance between the source and drain of MOSFET Q1 is relatively small, thereby ensuring that the input power supply works normally.

[0044] The RC network module 2 contains a selection control circuit. By selecting different values ​​of resistor R1 and capacitor C1 through the switching circuit, the charging delay time of the RC network is adjusted, thereby controlling the suppression time of the power-on inrush current. This ensures that MOSFET Q1 is turned on only after the inrush current is completely suppressed.

[0045] Since different load characteristics correspond to different inrush current magnitudes, the delay time of the corresponding RC network needs to be set differently. A sampling resistor R5 is connected in series at the IN+ terminal. The magnitude of the power-on inrush current is determined by detecting the voltage across R5. Therefore, the detection value is fed back to the control circuit of the RC network through the inrush current detection module. The control circuit adjusts the delay time of the RC network to adjust the magnitude of the inrush current, thereby realizing adaptive adjustment of the inrush current magnitude for different loads.

[0046] During the initial power-on phase, capacitor C1 is slowly charged through resistor R1. MOSFET Q1 is in the linear region, and Rds impedance is high, thereby suppressing the inrush current. The current detection circuit monitors the magnitude of the inrush current through resistor R5 and feeds it back to RC network module 2.

[0047] During the adaptive adjustment phase, if the inrush current is large, the control circuit increases the value of resistor R1 or capacitor C1 to extend the soft-start time of MOSFET Q1. If the inrush current is small, the delay is shortened to quickly turn on MOSFET Q1.

[0048] During the steady-state phase, after capacitor C1 is charged to the threshold voltage of MOSFET Q1, MOSFET Q1 is fully turned on, the Rds value is small, and the circuit enters a low-loss operating mode.

[0049] In summary, by utilizing the above-mentioned technical solution of this utility model, the RC parameters of the surge suppression circuit are automatically controlled based on the starting current to adjust the starting time. A current detection module 4 is designed to detect the system current and feed it back to the starting control circuit. The control circuit adjusts the RC time constant according to the system current level to control the starting time of the field-effect transistor Q1. Simultaneously, the reverse connection protection diode D1 and the isolation diode D2 ensure the unidirectionality of the supply current, guaranteeing the consistency of the RC time constant during cold and hot starts, thus ensuring consistent system starting time. Furthermore, the Zener diode D3 ensures the minimum turn-on voltage of the field-effect transistor Q1. Resistor R3 and capacitor C2 ensure the steady-state turn-on and turn-off of the field-effect transistor Q1. This utility model, by designing the reverse connection protection diode D1 and the isolation diode D2, ensures the consistency of RC parameters during cold and hot starts. Based on the RC network and control circuit, it automatically adjusts the turn-on time of Q1. The field-effect transistor Q1 is placed on the negative terminal of the circuit to ensure that its turn-on voltage does not fluctuate due to changes in load current.

[0050] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A direct current surge current suppression circuit with automatic adjustment, characterized by, The suppression circuit includes: The auxiliary module (1) is used to connect to the power supply and control the consistency during the charging process to avoid circuit damage caused by reverse connection of the power supply. The RC network module (2) is used to receive circuit signals and dynamically adjust the charging time constant according to the circuit signals to control the opening of the switch (3); Switch (3) is used to limit the inrush current and ensure normal power supply; The current detection module (4) is used to detect the inrush current and convert it into a voltage signal, and to provide feedback on the current level. The output terminal of the auxiliary module (1) is connected to the input terminal of the RC network module (2), the output terminal of the RC network module (2) is connected to the input terminal of the switch (3), and the output terminal of the switch (3) is connected to the input terminal of the current detection module (4).

2. The DC inrush current suppression circuit with automatic adjustment according to claim 1, characterized in that, The auxiliary module (1) includes a reverse polarity protection diode D1, an isolation diode D2, a gate protection Zener diode D3, a resistor R3, a resistor R2, a capacitor C2, and a capacitor C4. One end of the anti-reverse connection diode D1 is connected to one end of the RC network module (2) and one end of the isolation diode D2, respectively. The other end of the isolation diode D2 is connected to one end of the capacitor C4 and one end of the current detection module (4), respectively. The other end of the capacitor C4 is connected to one end of the switch (3). One end of the resistor R2 is connected to one end of the RC network module (2), one end of the gate protection Zener diode D3 and one end of the resistor R3 respectively. The other end of the resistor R2 is connected to the other end of the RC network module (2), the other end of the gate protection Zener diode D3 and one end of the capacitor C2 respectively. The other end of the capacitor C2 is connected to the other end of the resistor R3 and one end of the switch (3) respectively.

3. The DC inrush current suppression circuit with automatic adjustment according to claim 2, characterized in that, The reverse connection protection diode D1 is used to prevent the circuit from being damaged by reverse connection of the power supply. The isolation diode D2 is used to prevent the capacitor C4 on the load side from affecting the charging consistency of the RC network module (2). The gate protection Zener diode D3 is used to prevent the switch (3) from being over-voltaged and broken down. The capacitor C2 and the resistor R3 are used to stabilize the drive signal of the switch (3).

4. The DC inrush current suppression circuit with automatic adjustment according to claim 3, characterized in that, The RC network module (2) includes a resistor R1 and a capacitor C1; One end of the resistor R1 is connected to one end of the reverse polarity protection diode D1 and one end of the isolation diode D2, respectively; the other end of the resistor R1 is connected to one end of the capacitor C1, one end of the resistor R2 and one end of the resistor R3, respectively. The other end of the capacitor C1 is connected to the other end of the resistor R2, the other end of the capacitor C2, and one end of the switch (3).

5. A DC inrush current suppression circuit with automatic adjustment according to claim 1, characterized in that, The switch (3) is connected in series at the negative line of the circuit and presents high impedance when the gate voltage does not reach the threshold, limiting the inrush current. After being fully turned on, the impedance drops to the minimum, ensuring normal power supply.

6. A DC inrush current suppression circuit with automatic adjustment according to claim 4, characterized in that, The switch (3) is a field-effect transistor Q1, and the source of the field-effect transistor Q1 is connected to one end of the capacitor C2, one end of the gate protection Zener diode D3, one end of the resistor R2 and one end of the capacitor C1, respectively. The gate of the field-effect transistor Q1 is connected to one end of the resistor R3 and the other end of the capacitor C2, respectively. The drain of the field-effect transistor Q1 is connected to one end of the capacitor C4.

7. A DC inrush current suppression circuit with automatic adjustment according to claim 1, characterized in that, The current detection module (4) is connected in series with the sampling resistor R5 of the output positive line to detect the inrush current and convert it into a voltage signal, which is then output to the control circuit of the RC network module (2) and feedback the current level.

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