Suppression circuit for surge current during power supply starting

Abstract

The utility model provides a suppression circuit for surge current during power supply starting. The suppression circuit comprises a power supply insurance module, a rectification module, an auxiliary power supply module and a main power circuit module. The input end of the rectifier module is connected with a power supply through the power supply fuse module, the output end of the rectifier module is sequentially connected with the auxiliary power supply module and the main power circuit module, and the auxiliary power supply module is connected with the main power circuit module so as to provide VCC power supply for the main power circuit module; the input end of the auxiliary power supply module is connected with the output end of the rectification module, and the grounding end is grounded through an NTC resistor. The input end of the main power circuit module is connected with the output end of the rectification module, and the grounding end is grounded through at least one surge protection module. The suppression circuit for the surge current when the power supply is started has the advantages of being simple in structure, flexible to use and high in applicability.

Description

Technical Field

[0001] The utility model belongs to the field of electronic technology, and in particular relates to a circuit for suppressing surge current when a power supply is started. Background Art

[0002] Surge current is the culprit for the short life and failure of electrical equipment and electronic components, and is also a potential threat to the stability of the power supply network and personal safety. Adding a surge current suppression circuit to the power supply can effectively avoid the impact of surge current and ensure the safety of equipment and personnel.

[0003] The existing power supply will generate a high surge current when it is powered on. Therefore, a soft start device to prevent surge current must be installed at the input end of the power supply to effectively reduce the surge current to the allowable range. The surge current is mainly caused by the charging of the filter capacitor. At the moment when the switch tube starts to conduct, the capacitor presents a low impedance. If no protective measures are taken, the surge current is large and may cause failure of fuses and other electrical equipment. Therefore, a specific circuit is required to suppress the large surge current.

[0004] Conventional surge current suppression circuits usually connect an NTC resistor in series with the power filter capacitor to suppress surge current by using its characteristics. However, after the power supply enters normal operation, the NTC is still connected in series with the circuit, which causes large power consumption of the whole machine, reduces efficiency, and is also prone to cause additional temperature rise of the whole machine. Some power supplies are connected to relay control, and after the power supply enters normal operation, the NTC is short-circuited to reduce overall losses. Although this method avoids the problem of high working losses after connecting the NTC resistor, it introduces timing control, which is also a test for relays for some high-current circuits, indirectly increasing the difficulty of production and production costs, resulting in poor flexibility and applicability of existing surge current suppression circuits in actual use. Utility Model Content

[0005] In view of this, the utility model aims to provide a surge current suppression circuit for power startup, so as to solve the problem that the existing surge current suppression circuit has poor flexibility and applicability in actual use.

[0006] In order to achieve the above object, the technical solution of the utility model is implemented as follows:

[0007] A circuit for suppressing surge current when a power supply is started, comprising a power supply fuse module, a rectifier module, an auxiliary power supply module, and a main power circuit module; the input end of the rectifier module is connected to a power supply through the power supply fuse module, and the output end is connected to the auxiliary power supply module and the main power circuit module in sequence, and the auxiliary power supply module is connected to the main power circuit module to provide VCC power supply for the main power circuit module;

[0008] The input end of the auxiliary power module is connected to the output end of the rectifier module, and the ground end is grounded through an NTC resistor;

[0009] The input end of the main power circuit module is connected to the output end of the rectifier module, and the ground end is grounded through at least one surge protection module;

[0010] The surge protection module includes a MOS tube Qn, a voltage-regulating diode ZDn, and a voltage-dividing resistor Rn; the G pole of the MOS tube Qn receives a power supply signal VCC through the voltage-dividing resistor Rn, the D pole is connected to the ground end of the main power circuit module, and the S pole is grounded; the cathode of the voltage-regulating diode ZDn is connected to the G pole of the MOS tube Qn, and the anode is grounded.

[0011] Furthermore, one end of the voltage-dividing resistor Rn is connected to the G pole of the MOS tube Qn, and the other end is grounded through the bus electrolytic capacitor C3.

[0012] Furthermore, one end of the voltage-dividing resistor Rn is connected to the G pole of the MOS tube Qn, and the other end receives the power supply signal VCC through the voltage-dividing resistor R0.

[0013] Furthermore, a plurality of surge protection modules are provided, and after being connected in parallel, the input end of each surge protection module is connected to the ground end of the main power circuit module, and the ground end is grounded.

[0014] Compared with the prior art, the circuit for suppressing surge current when the power supply is started described in the utility model has the following advantages:

[0015] The utility model discloses a surge current suppression circuit for power supply startup, which has the advantages of simple structure, flexible use, strong applicability and no voltage limitation. By connecting the surge protection module in series in the protected circuit, the surge current value generated during the power supply startup process can be effectively suppressed, thereby achieving effective protection of the circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation on the present invention. In the accompanying drawings:

[0017] Figure 1 It is a circuit structure schematic diagram of an existing conventional surge current suppression circuit;

[0018] Figure 2 A schematic diagram of the circuit structure of an existing relay control surge current suppression circuit;

[0019] Figure 3A schematic diagram of a circuit structure when a surge protection module is provided in a circuit for suppressing surge current when a power supply is started according to an embodiment of the utility model;

[0020] Figure 4 The present invention is a schematic diagram of a circuit structure in which n surge protection modules are arranged in a circuit for suppressing surge current when a power supply is started, as described in an embodiment of the present invention. DETAILED DESCRIPTION

[0021] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other.

[0022] In the description of the present utility model, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present utility model. In addition, the terms "first", "second", etc. are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, features defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of the present utility model, unless otherwise specified, "multiple" means two or more.

[0023] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood by specific circumstances.

[0024] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments.

[0025] An embodiment of the present invention provides a circuit for suppressing surge current when a power supply is started, comprising a power supply fuse module, a rectifier module, an auxiliary power supply module, and a main power circuit module; the input end of the rectifier module is connected to the power supply through the power supply fuse module, and the output end is connected to the auxiliary power supply module and the main power circuit module in sequence, and the auxiliary power supply module is connected to the main power circuit module to provide VCC power supply for the main power circuit module.

[0026] Figure 1 The following is a schematic diagram of the circuit structure of an existing conventional surge current suppression circuit. Figure 1 The existing conventional surge current suppression circuit is the same as the Forbidden City. An NTC resistor is connected in series with the power filter capacitor to utilize its characteristics to suppress the surge current.

[0027] Figure 2 This is a schematic diagram of the circuit structure of an existing relay control surge current suppression circuit. Figure 2 The existing relay controls the surge current suppression circuit. By accessing the relay control, after the power supply enters normal operation, the NTC is short-circuited to reduce the overall loss.

[0028] The main improvement of the utility model lies in the improvement of the surge protection module and the overall design of the suppression circuit, and does not involve improvements to the power fuse module, the rectifier module, the auxiliary power module, and the main power circuit module. The power fuse module can adopt the fuse circuit in the existing power supply, the rectifier module can adopt the existing rectifier bridge circuit, and the auxiliary power module and the main power circuit module can both adopt the existing circuits, so they are not repeated here.

[0029] Specifically, Figure 3 and Figure 4 As shown, the input end of the auxiliary power module is connected to the output end of the rectifier module, and the ground end is grounded through an NTC resistor, wherein C2 is the busbar electrolysis of the auxiliary power module. The input end of the main power circuit module is connected to the output end of the rectifier module, and the ground end is grounded through at least one surge protection module, wherein C1 is the busbar electrolysis of the main power module. The surge protection module includes a MOS tube Qn, a voltage-regulating diode ZDn, and a voltage-dividing resistor Rn; the G pole of the MOS tube Qn receives the power supply signal VCC through the voltage-dividing resistor Rn, the D pole is connected to the ground end of the main power circuit module, and the S pole is grounded; the cathode of the voltage-regulating diode ZDn is connected to the G pole of the MOS tube Qn, and the anode is grounded. Among them, at least one surge protection module is set, and the surge protection modules can be used in a superimposed manner according to different application requirements.

[0030] In the actual application process, this suppression circuit can utilize the working mode of the MOS transistor. The power supply is rectified and then supplied to the auxiliary power supply module. During this process, since there is no chip power supply signal VCC on the main path output, the main path will not start working. When the auxiliary power supply module starts, it provides the power supply signal VCC. The gate of the MOS transistor Qn is charged through the voltage-dividing resistor Rn. When VGS > VGS(th) and VDS < VGS - VGS(th) are satisfied, the MOS transistor Qn enters the variable resistance region; in the variable resistance region, ID increases as VDS increases, and the two are basically linearly related. In addition, the resistance value of RDS will be different for different VGS. The RDS(ON) parameter generally seen in the MOS transistor data sheet is the on-resistance value in the variable resistance region. By utilizing the working characteristics of the saturation region of the MOS transistor Qn, the large inrush current during the startup of the power supply can be effectively suppressed.

[0031] Optionally, one end of the voltage-dividing resistor Rn is connected to the G pole of the MOS transistor Qn, and the other end is grounded through the bus electrolytic capacitor C3.

[0032] Optionally, one end of the voltage-dividing resistor Rn is connected to the G pole of the MOS transistor Qn, and the other end receives the power supply signal VCC through the voltage-dividing resistor R0. Among them, the power supply signal VCC can be provided by the auxiliary power supply module.

[0033] Optionally, one surge protection module is set, as Figure 3 shown. Then the surge protection module includes the MOS transistor Q1, the zener diode ZD1, and the voltage-dividing resistor R1; the G pole of the MOS transistor Q1 receives the power supply signal VCC through the voltage-dividing resistor R1, the D pole is connected to the grounding end of the main power circuit module, and the S pole is grounded; the cathode of the zener diode ZD1 is connected to the G pole of the MOS transistor Q1, and the anode is grounded. Among them, one end of the voltage-dividing resistor R1 is connected to the G pole of the MOS transistor Q1, and the other end is grounded through the bus electrolytic capacitor C3 and receives the power supply signal VCC through the voltage-dividing resistor R0.

[0034] Optionally, multiple surge protection modules are set, as Figure 4 shown. After the input ends of the surge protection modules are connected in parallel, they are connected to the grounding end of the main power circuit module, and the grounding end is grounded. Exemplarily, two, three, or n surge protection modules can be set. When n surge protection modules are set, the grounding end of the main power circuit module is grounded through n surge protection modules connected in parallel. Among them, the corresponding MOS transistor Qn, zener diode ZDn, and voltage-dividing resistor Rn, where n is equal to 1, 2, 3......

[0035] In the actual application process, this suppression circuit can utilize the working characteristics of the MOS transistor in the variable resistance region to effectively suppress the large inrush current during the cold start of the power supply.

[0036] Specifically, C2 is the bus electrolytic capacitor of the auxiliary power supply module, and C1 is the bus electrolytic capacitor of the main power circuit module. The auxiliary power supply module provides VCC power supply for the main power circuit module. At the moment of startup, the capacitor presents a low impedance, and a large inrush current will be generated in the circuit. The addition of the NTC resistor effectively reduces the inrush current of the auxiliary power supply circuit. F1 and F2 are the fuses for power input (i.e., the power supply fuse module), and BD1 is the rectifier bridge (i.e., the rectifier bridge module).

[0037] Among them, R0 and Rn are voltage-dividing resistors. By adjusting the resistance values, the MOS transistor Qn in the surge protection module operates in the variable resistance region, that is, VGS > VGS(th), and VDS < VGS - VGS(th). In this stage, the inrush current in the main power loop can be effectively suppressed. As the VDS voltage continuously rises, when VDS > VGS - VGS(th), the MOS transistor Qn presents a fully conducting state. At this time, since the bus electrolytic capacitor C1 has accumulated a certain amount of charge and the impedance increases, no large inrush current is generated in the main loop, and the circuit operates normally at this time.

[0038] In addition, it is worth noting that this type of circuit has requirements for the drain-source current of the MOS transistor Qn. The maximum current when the circuit is stable needs to be less than the maximum withstand value of the drain-source current of the MOS transistor Qn. Multiple MOS transistors Qn can be selected in parallel in this circuit to increase the bearing capacity and compatibility of the circuit.

[0039] The inrush current suppression circuit for power startup described in the present utility model has the advantages of simple structure, flexible use, strong applicability, and no voltage limitation. By connecting the surge protection module in series in the protected circuit, the inrush current value generated during the power-on process of the power supply startup can be effectively suppressed, thereby achieving effective protection for the circuit.

[0040] The above are only the preferred embodiments of the present utility model and are not intended to limit the present utility model. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present utility model shall be included in the protection scope of the present utility model.

Claims

1. A circuit for suppressing surge current when a power supply is started, comprising a power supply fuse module, a rectifier module, an auxiliary power supply module, and a main power circuit module; the input end of the rectifier module is connected to the power supply through the power supply fuse module, and the output end is connected to the auxiliary power supply module and the main power circuit module in sequence, the auxiliary power supply module is connected to the main power circuit module to provide VCC power supply for the main power circuit module, characterized in that: The input end of the auxiliary power module is connected to the output end of the rectifier module, and the ground end is grounded through an NTC resistor; The input end of the main power circuit module is connected to the output end of the rectifier module, and the ground end is grounded through at least one surge protection module; The surge protection module includes a MOS tube Qn, a voltage-regulating diode ZDn, and a voltage-dividing resistor Rn; the G pole of the MOS tube Qn receives a power supply signal VCC through the voltage-dividing resistor Rn, the D pole is connected to the ground end of the main power circuit module, and the S pole is grounded; the cathode of the voltage-regulating diode ZDn is connected to the G pole of the MOS tube Qn, and the anode is grounded.

2. The circuit for suppressing surge current when a power supply is started according to claim 1, characterized in that: One end of the voltage-dividing resistor Rn is connected to the G pole of the MOS tube Qn, and the other end is grounded through the bus electrolytic capacitor C3.

3. The circuit for suppressing surge current when a power supply is started according to claim 1, characterized in that: One end of the voltage-dividing resistor Rn is connected to the G pole of the MOS tube Qn, and the other end receives the power supply signal VCC through the voltage-dividing resistor R0.

4. A circuit for suppressing surge current when a power supply is started according to any one of claims 1 to 3, characterized in that: There are multiple surge protection modules, and after the surge protection modules are connected in parallel, the input end is connected to the ground end of the main power circuit module, and the ground end is grounded.

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