Surge current suppression circuit, switching power supply circuit and charger

Abstract

The utility model discloses a surge current suppression circuit, a switching power supply circuit and a charger, the surge current suppression circuit is arranged between a rectifier module and an electrolytic capacitor, and the surge current suppression circuit comprises a control chip, a voltage detection module and a switch module; the voltage detection module is used for outputting a sampling voltage to the control chip according to the DC voltage output by the rectifier module; the switch module is arranged between the cathode output end of the rectifier module and the second end of the electrolytic capacitor; the control chip is further connected with the switch module and used for controlling the switch module to be switched on when the sampling voltage is smaller than the reference voltage. The surge current suppression circuit can judge whether the direct-current voltage output by the rectifier module is close to the zero phase or not, and when the phase of the direct-current voltage is close to the zero phase, the rectifier module is controlled to charge the electrolytic capacitor, so that surge current formed by high-voltage large-current charging of the electrolytic capacitor can be prevented, and power loss is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of switching power supplies, in particular to a surge current suppression circuit, a switching power supply circuit and a charger. Background Art

[0002] The switching power supply circuit will have a large surge current at the moment of power on. If no measures are taken, it is easy to cause the electronic components in the circuit to fail, greatly reducing the reliability of the product.

[0003] In the prior art, a thermistor is usually added between the rectifier module and the electrolytic capacitor of the switching power supply to suppress the surge current. However, the added thermistor is prone to generate large power loss and may also cause problems such as circuit heating, resulting in poor surge suppression effect. Utility Model Content

[0004] The embodiments of the utility model provide an inrush current suppression circuit, a switching power supply circuit and a charger to solve the problem that the inrush current suppression effect of the switching power supply is poor.

[0005] The utility model embodiment provides a surge current suppression circuit, which is arranged between a rectifier module and an electrolytic capacitor, and includes a control chip, a voltage detection module and a switch module;

[0006] The first end of the voltage detection module is connected to the connection node between the positive output end of the rectifier module and the first end of the electrolytic capacitor, and the second end of the voltage detection module is connected to the control chip, and is used to output a sampling voltage to the control chip according to the DC voltage output by the rectifier module;

[0007] The switch module is arranged between the positive output terminal of the rectifier module and the first end of the electrolytic capacitor, or the switch module is arranged between the negative output terminal of the rectifier module and the second end of the electrolytic capacitor;

[0008] The control chip is also connected to the switch module, and is used to control the switch module to be turned on when the sampled voltage is less than the reference voltage.

[0009] Preferably, the voltage detection module includes a first resistor and a second resistor;

[0010] The first end of the first resistor is connected to a connection node between the positive output end of the rectifier module and the first end of the electrolytic capacitor, the second end of the first resistor is connected to the first end of the second resistor, and the second end of the second resistor is grounded;

[0011] A connection node between the first resistor and the second resistor is connected to a first sampling terminal of the control chip, and is used to output a sampling voltage to the control chip.

[0012] Preferably, the voltage detection module further includes a filter capacitor;

[0013] A first end of the filter capacitor is connected to a connection node between the first resistor and the second resistor, and a second end of the filter capacitor is grounded.

[0014] Preferably, the switch module comprises a switch tube;

[0015] The first end of the switch tube is connected to the positive output end of the rectifier module, and the second end of the switch tube is connected to the first end of the electrolytic capacitor, or the first end of the switch tube is connected to the second end of the electrolytic capacitor, and the second end of the switch tube is grounded;

[0016] The third end of the switch tube is connected to the control end of the control chip and is used for being turned on or off under the control of the control chip.

[0017] Preferably, the switch module further includes a third resistor;

[0018] The first end of the third resistor is connected to the second end of the switch tube, and the second end of the third resistor is connected to the third end of the switch tube.

[0019] Preferably, the surge current suppression circuit further includes a reference voltage generation module;

[0020] The input end of the reference voltage generation module is connected to the input end of the rectifier module, and the output end of the reference voltage generation module is connected to the second sampling end of the control chip for outputting the reference voltage to the control chip.

[0021] Preferably, the reference voltage generating module comprises a rectifying unit and a voltage stabilizing unit;

[0022] The input end of the rectifier unit is connected to the input end of the rectifier module, and the output end of the rectifier unit is connected to the first end of the voltage stabilizing unit and the power supply end of the control chip, so as to provide a power supply voltage to the voltage stabilizing unit and the control chip;

[0023] The second end of the voltage stabilizing unit is connected to the second sampling end of the control chip, and is used to output a reference voltage to the control chip.

[0024] Preferably, the voltage stabilizing unit comprises a voltage stabilizing tube and a fourth resistor;

[0025] The first end of the voltage regulator is connected to the output end of the rectifier unit through a fourth resistor, the second end of the voltage regulator is grounded, and the first end of the voltage regulator is connected to the control chip for clamping the voltage of the second sampling end of the control chip to a reference voltage.

[0026] The embodiment of the utility model further provides a switching power supply circuit, comprising a rectifier module, an electrolytic capacitor and any one of the above-mentioned surge current suppression circuits;

[0027] The input end of the rectifier module is used to connect to the mains circuit;

[0028] The positive output end of the rectifier module is connected to the first end of the electrolytic capacitor through the switch module, the second end of the electrolytic capacitor is grounded, the voltage detection module is connected to the connection node between the rectifier module and the switch module, or the positive output end of the rectifier module is connected to the voltage detection module and the first end of the electrolytic capacitor, and the second end of the electrolytic capacitor is connected to the switch module.

[0029] An embodiment of the utility model further provides a charger, comprising the above-mentioned switching power supply circuit.

[0030] The inrush current suppression circuit, switching power supply circuit and charger provided by the embodiments of the utility model can determine whether the DC voltage output by the rectifier module is near the 0 phase by sampling the DC voltage output by the rectifier module and comparing the sampled voltage obtained by sampling with the reference voltage. When the phase of the DC voltage is close to the 0 phase, the rectifier module is controlled to charge the electrolytic capacitor, which can prevent high voltage from charging the electrolytic capacitor with a large current to form a surge current. There is no need to add a thermistor in the circuit to prevent the generation of surge current, thereby reducing power loss. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions of the embodiments of the utility model, the drawings required for use in the description of the embodiments of the utility model will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0032] Figure 1 This is a circuit diagram of a switching power supply circuit in one embodiment of the utility model;

[0033] Figure 2 It is a voltage waveform diagram of a DC voltage in one embodiment of the utility model.

[0034] In the figure: 1. voltage detection module; 2. switch module; 3. reference voltage generation module; 31. voltage stabilization unit. DETAILED DESCRIPTION

[0035] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0036] It should be understood that the utility model can be implemented in different forms and should not be construed as being limited to the embodiments presented herein. On the contrary, providing these embodiments will make the disclosure thorough and complete, and fully convey the scope of the utility model to those skilled in the art. In the accompanying drawings, the sizes and relative sizes of layers and regions may be exaggerated for clarity. The same reference numerals throughout represent the same elements.

[0037] It should be understood that when an element or layer is referred to as being "on, adjacent to, connected to or coupled to other elements or layers, it may be directly on, adjacent to, connected to or coupled to other elements or layers, or there may be intervening elements or layers. On the contrary, when an element is referred to as being "directly on, directly adjacent to, directly connected to or directly coupled to other elements or layers, there are no intervening elements or layers. It should be understood that although the terms first, second, third, etc. may be used to describe various elements, components, regions, layers and / or parts, these elements, components, regions, layers and / or parts should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or part from another element, component, region, layer or part. Therefore, without departing from the teachings of the present invention, the first element, component, region, layer or part discussed below may be represented as a second element, component, region, layer or part.

[0038] Spatially relative terms such as "under," "beneath," "below," "under," "above," "above," and the like may be used herein for ease of description to describe the relationship of an element or feature shown in the figures to other elements or features. It should be understood that the spatially relative terms are intended to include different orientations of the device in use and operation in addition to the orientations shown in the figures. For example, if the device in the accompanying drawings is flipped, then the elements or features described as "under other elements" or "under" or "under" will be oriented as "above" the other elements or features. Thus, the exemplary terms "under" and "under" may include both upper and lower orientations. The device may be otherwise oriented (rotated 90 degrees or other orientations) and the spatial descriptors used herein are interpreted accordingly.

[0039] The purpose of the terms used herein is only to describe specific embodiments and is not intended to be a limitation of the present invention. When used herein, the singular forms "one", "an" and "said / the" are also intended to include plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "consisting of" and / or "comprising" when used in this specification determine the presence of the features, integers, steps, operations, elements and / or parts, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, parts and / or groups. When used herein, the term "and / or" includes any and all combinations of the relevant listed items.

[0040] In order to thoroughly understand the present invention, detailed structures and steps will be presented in the following description to illustrate the technical solution proposed by the present invention. The preferred embodiments of the present invention are described in detail below, but in addition to these detailed descriptions, the present invention may also have other implementations.

[0041] The utility model provides a surge current suppression circuit. Figure 1 As shown, the surge current suppression circuit is arranged between the rectifier module BD1 and the electrolytic capacitor EC1, including a control chip U1, a voltage detection module 1 and a switch module 2; the first end of the voltage detection module 1 is connected to the connection node between the positive output end of the rectifier module BD1 and the first end of the electrolytic capacitor EC1, and the second end of the voltage detection module 1 is connected to the control chip U1, and is used to output a sampling voltage to the control chip U1 according to the DC voltage Uo output by the rectifier module BD1; the switch module 2 is arranged between the positive output end of the rectifier module BD1 and the first end of the electrolytic capacitor EC1, or the switch module 2 is arranged between the negative output end of the rectifier module BD1 and the second end of the electrolytic capacitor EC1; the control chip U1 is also connected to the switch module 2, and is used to control the switch module 2 to be turned on when the sampling voltage is less than the reference voltage.

[0042] The sampling voltage is the voltage obtained by the voltage detection module 1 according to the DC voltage Uo output by the rectifier module BD1, and there is a proportional conversion relationship between the voltage value of the sampling voltage and the voltage value of the DC voltage Uo. The reference voltage is a pre-set voltage used to determine whether the phase of the DC voltage Uo output by the rectifier module BD1 corresponding to the sampling voltage is close to the 0 phase voltage.

[0043] As an example, the surge current suppression circuit can be arranged between the rectifier module BD1 and the electrolytic capacitor EC1 in the switching power supply circuit, and includes a control chip U1, a voltage detection module 1 and a switch module 2. The first end of the voltage detection module 1 is connected to the connection node between the positive output terminal of the rectifier module BD1 and the first end of the electrolytic capacitor EC1, and the second end of the voltage detection module 1 is connected to the first sampling terminal IN- of the control chip U1. The first end of the switch module 2 can be connected to the positive output terminal of the rectifier module BD1, and the second end of the switch module 2 is connected to the first end of the electrolytic capacitor EC1, or the first end of the switch module 2 can also be connected to the second end of the electrolytic capacitor EC1, and the second end of the switch module 2 is connected to the negative output terminal of the rectifier module BD1, and the third end of the switch module 2 is connected to the control terminal Gate of the control chip U1.

[0044] In this example, the rectifier module BD1 is used to convert the input 50HZ sine wave AC voltage into Figure 2 The DC voltage Uo shown only contains the positive half-wave of the sine wave, and the period of the DC voltage Uo is 10ms. When the phase is 90 degrees, the voltage value is the highest, and when the phase is 0 degrees, the voltage value is the lowest. The voltage detection module 1 is used to output a sampling voltage corresponding to the magnitude of the DC voltage Uo to the control chip U1 according to the rectified DC voltage Uo output by the rectifier module BD1. After the switching power supply circuit is turned on, when the control chip U1 detects that the sampling voltage is less than the reference voltage, it indicates that the phase of the DC voltage Uo output by the current rectifier module BD1 is close to the 0 phase. At this time, the control chip U1 controls the switch module 2 to form a complete charging circuit between the rectifier module BD1 and the electrolytic capacitor EC1, which can prevent the high voltage from charging the electrolytic capacitor EC1 with a large current to form a surge current, avoid adding a thermistor in the circuit to prevent the generation of surge current, and reduce power loss.

[0045] In order to further control the inrush current when the switching power supply circuit is turned on, the control chip U1 can control the switch module 2 to be turned on for a first time period in each half-wave cycle of the sine wave of the DC voltage Uo before the first time after the power is turned on, and control the switch module 2 to be turned on continuously after the first time. For example, the control chip U1 can control the switch module 2 to be turned on for 3.5ms in each cycle in the first five cycles after the power is turned on, and control the switch module 2 to be turned on continuously after the start of the sixth cycle, that is, when the sampling voltage is detected to be less than the reference voltage for the first five times, the switch module 2 is controlled to be turned on continuously for 3.5ms, and when the sampling voltage is detected to be less than the reference voltage for the sixth time, the switch module 2 is controlled to be turned on continuously to reduce the inrush current and protect the electronic components.

[0046] In one embodiment, the voltage detection module 1 includes a first resistor R1 and a second resistor R2; the first end of the first resistor R1 is connected to the connection node between the positive output end of the rectifier module BD1 and the first end of the electrolytic capacitor EC1, the second end of the first resistor R1 is connected to the first end of the second resistor R2, and the second end of the second resistor R2 is grounded; the connection node between the first resistor R1 and the second resistor R2 is connected to the first sampling terminal IN- of the control chip U1, for outputting the sampling voltage to the control chip U1.

[0047] As an example, the voltage detection module 1 includes a first resistor R1 and a second resistor R2; the first end of the first resistor R1 is connected to the connection node between the positive output end of the rectifier module BD1 and the first end of the electrolytic capacitor EC1, the second end of the first resistor R1 is connected to the first end of the second resistor R2, and the second end of the second resistor R2 is grounded; the connection node between the first resistor R1 and the second resistor R2 is connected to the first sampling terminal IN- of the control chip U1. During the operation of the circuit, the first resistor R1 and the second resistor R2 form a voltage dividing effect on the DC voltage Uo output by the rectifier module BD1, and the sampling voltage output to the control chip U1 is the same as the voltage across the second resistor R2.

[0048] In one embodiment, the voltage detection module 1 further includes a filter capacitor C1 ; a first end of the filter capacitor C1 is connected to a connection node between the first resistor R1 and the second resistor R2 , and a second end of the filter capacitor C1 is grounded.

[0049] As an example, the voltage detection module 1 further includes a filter capacitor C1. A first end of the filter capacitor C1 is connected to a connection node between the first resistor R1 and the second resistor R2, and a second end of the filter capacitor C1 is grounded, for filtering interference signals in the sampled voltage.

[0050] In one embodiment, the switch module 2 includes a switch tube Q1; the first end of the switch tube Q1 is connected to the positive output end of the rectifier module BD1, and the second end of the switch tube Q1 is connected to the first end of the electrolytic capacitor EC1, or the first end of the switch tube Q1 is connected to the second end of the electrolytic capacitor EC1, and the second end of the switch tube Q1 is grounded; the third end of the switch tube Q1 is connected to the control end Gate of the control chip U1, and is used to turn on or off under the control of the control chip U1.

[0051] As an example, the switch module 2 includes a switch tube Q1. The switch tube Q1 may be an NMOS tube, the first end of the switch tube Q1 is the drain of the NMOS tube, the second end of the switch tube Q1 is the source of the NMOS tube, and the third end of the switch tube Q1 is the gate of the NMOS tube. The drain of the NMOS tube is connected to the positive output end of the rectifier module BD1, and the source of the NMOS tube is connected to the first end of the electrolytic capacitor EC1, or, as Figure 1As shown, the drain of the NMOS tube is connected to the second end of the electrolytic capacitor EC1, and the source of the NMOS tube is grounded. The gate of the NMOS tube is connected to the control terminal Gate of the control chip U1. When the sampling voltage is less than the reference voltage, the control chip U1 outputs a high level to the gate of the NMOS tube, controls the NMOS tube to be turned on, and forms a complete current loop between the rectifier module BD1 and the electrolytic capacitor EC1.

[0052] In order to further control the surge current when the switching power supply circuit is turned on, the control chip U1 can control the opening time of the NMOS tube to 3.5ms in the first five cycles after power-on, and continuously output a high level to the NMOS tube after the start of the sixth cycle, so that the NMOS tube is in a continuously turned-on state to reduce the surge current and protect the electronic components.

[0053] In one embodiment, the switch module 2 further includes a third resistor R3; a first end of the third resistor R3 is connected to the second end of the switch tube Q1, and a second end of the third resistor R3 is connected to the third end of the switch tube Q1.

[0054] As an example, the switch module 2 further includes a third resistor R3, which is disposed between the second end and the third end of the switch tube Q1, and is used to provide a bias voltage to the switch tube Q1 to ensure its normal operation. For example, when the switch tube Q1 is an NMOS tube, the first end of the third resistor R3 is connected to the source of the NMOS tube, and the second end of the third resistor R3 is connected to the gate of the NMOS tube, and is used to provide a bias voltage to the NMOS tube.

[0055] In one embodiment, the surge current suppression circuit also includes a reference voltage generating module 3; the input end of the reference voltage generating module 3 is connected to the input end of the rectifier module BD1, and the output end of the reference voltage generating module 3 is connected to the second sampling end IN+ of the control chip U1, for outputting a reference voltage to the control chip U1.

[0056] As an example, the surge current suppression circuit also includes a reference voltage generation module 3. The input end of the reference voltage generation module 3 is connected to the input end of the rectifier module BD1, and is used to be connected to the mains circuit when the input end of the rectifier module BD1 is connected to the mains circuit. The output end of the reference voltage generation module 3 is connected to the second sampling end IN+ of the control chip U1, and is used to output a reference voltage to the control chip U1. When the rectifier module BD1 is connected to the mains circuit, the reference voltage generation module 3 is synchronously connected to the mains circuit, converts the alternating current into a reference voltage, and outputs it to the second sampling end IN+ of the control chip U1. When the sampling voltage received by the control chip U1 at the first sampling end IN- is less than the reference voltage, the switch module 2 is controlled to be turned on, so that a complete charging circuit is formed between the rectifier module BD1 and the electrolytic capacitor EC1, which can prevent the high voltage from charging the electrolytic capacitor EC1 with a large current to form a surge current, avoid adding a thermistor in the circuit to prevent the generation of surge current, and reduce power loss.

[0057] In one embodiment, the reference voltage generating module 3 includes a rectifier unit BD2 and a voltage stabilizing unit 31; the input end of the rectifier unit BD2 is connected to the input end of the rectifier module BD1, and the output end of the rectifier unit BD2 is connected to the first end of the voltage stabilizing unit 31 and the power supply end VCC of the control chip U1, so as to provide a power supply voltage to the voltage stabilizing unit 31 and the control chip U1; the second end of the voltage stabilizing unit 31 is connected to the second sampling end IN+ of the control chip U1, so as to output a reference voltage to the control chip U1.

[0058] As an example, the reference voltage generating module 3 includes a rectifier unit BD2 and a voltage stabilizing unit 31. The input end of the rectifier unit BD2 is connected to the input end of the rectifier module BD1, the output end of the rectifier unit BD2 is connected to the first end of the voltage stabilizing unit 31 and the power supply end VCC of the control chip U1, and the second end of the voltage stabilizing unit 31 is connected to the second sampling end IN+ of the control chip U1. When the rectifier module BD1 is connected to the mains circuit, the rectifier unit BD2 in the reference voltage generating module 3 is synchronously connected to the mains circuit, converting the AC power into DC power and outputting it to the voltage stabilizing unit 31 and the power supply terminal VCC of the control chip U1, providing the control chip U1 with a power supply voltage. The voltage stabilizing unit 31 clamps the DC power output to the control chip U1 to a fixed value to form a reference voltage output to the control chip U1. When the sampling voltage received by the control chip U1 at the first sampling terminal IN- is less than the reference voltage, the switch module 2 is controlled to be turned on, so that a complete charging circuit is formed between the rectifier module BD1 and the electrolytic capacitor EC1, which can prevent the high voltage from charging the electrolytic capacitor EC1 with a large current to form a surge current, avoid adding a thermistor in the circuit to prevent the generation of surge current, and reduce power loss.

[0059] In one embodiment, the voltage stabilizing unit 31 includes a voltage stabilizing tube ZD1 and a fourth resistor R4; the first end of the voltage stabilizing tube ZD1 is connected to the output end of the rectifier unit BD2 through the fourth resistor R4, the second end of the voltage stabilizing tube ZD1 is grounded, and the first end of the voltage stabilizing tube ZD1 is connected to the control chip U1, and is used to clamp the voltage of the second sampling terminal IN+ of the control chip U1 to the reference voltage.

[0060] As an example, the voltage stabilizing unit 31 includes a voltage stabilizing tube ZD1 and a fourth resistor R4. The voltage stabilizing tube ZD1 may be a voltage stabilizing diode, the cathode of the voltage stabilizing diode is connected to the output end of the rectifier unit BD2 through the fourth resistor R4, the anode of the voltage stabilizing diode is grounded, and the cathode of the voltage stabilizing diode is connected to the second sampling end IN+ of the control chip U1. According to the reverse working characteristics of the voltage stabilizing diode, after the voltage stabilizing diode is reversely broken down, the voltage at both ends can be stabilized at a fixed voltage, so a fixed reference voltage can be formed at the second sampling end IN+ of the control chip U1.

[0061] An embodiment of the utility model also provides a switching power supply circuit, including a rectifier module BD1, an electrolytic capacitor EC1 and the surge current suppression circuit in any of the above embodiments; the input end of the rectifier module BD1 is used to connect to the AC power circuit; the positive output end of the rectifier module BD1 is connected to the first end of the electrolytic capacitor EC1 through the switch module 2, the second end of the electrolytic capacitor EC1 is grounded, the voltage detection module 1 is connected to the connection node between the rectifier module BD1 and the switch module 2, or the positive output end of the rectifier module BD1 is connected to the voltage detection module 1 and the first end of the electrolytic capacitor EC1, and the second end of the electrolytic capacitor EC1 is connected to the switch module 2.

[0062] As an example, the switching power supply circuit includes a rectifier module BD1, an electrolytic capacitor EC1 and an inrush current suppression circuit in any of the above examples. The input end of the rectifier module BD1 is used to connect to the mains circuit, and the switch module 2 in the inrush current suppression circuit is arranged on the current loop formed by the output end of the rectifier module BD1 and the electrolytic capacitor EC1, which can specifically include the following two connection modes: 1. The positive output end of the rectifier module BD1 is connected to the first end of the electrolytic capacitor EC1 through the switch module 2, the second end of the electrolytic capacitor EC1 is grounded, and the voltage detection module 1 in the inrush current suppression circuit is connected to the connection node between the rectifier module BD1 and the switch module 2; 2. The positive output end of the rectifier module BD1 is connected to the voltage detection module 1 and the first end of the electrolytic capacitor EC1, the second end of the electrolytic capacitor EC1 is connected to the first end of the switch module 2, and the second end of the switch module 2 is connected to the negative output end of the rectifier module BD1.

[0063] In this example, the rectifier module BD1 is used to convert the input 50HZ sine wave AC voltage into Figure 2The DC voltage Uo shown only contains the positive half-wave of the sine wave, and the period of the DC voltage Uo is 10ms. When the phase is 90 degrees, the voltage value is the highest, and when the phase is 0 degrees, the voltage value is the lowest. The electrolytic capacitor EC1 is used to make the pulsating DC voltage Uo output by the rectifier module BD1 smoother and reduce voltage fluctuations and noise. The voltage detection module 1 is used to output a sampling voltage corresponding to the magnitude of the DC voltage Uo to the control chip U1 according to the rectified DC voltage Uo output by the rectifier module BD1. After the switching power supply circuit is turned on, when the control chip U1 detects that the sampling voltage is less than the reference voltage, it indicates that the phase of the DC voltage Uo output by the current rectifier module BD1 is close to the 0 phase. At this time, the control chip U1 controls the switch module 2 to form a complete charging circuit between the rectifier module BD1 and the electrolytic capacitor EC1, which can prevent the high voltage from charging the electrolytic capacitor EC1 with a large current to form a surge current, avoid adding a thermistor in the circuit to prevent the generation of surge current, and reduce power loss.

[0064] An embodiment of the utility model further provides a charger, comprising the switching power supply circuit in the above embodiment.

[0065] As an example, the charger includes the switching power supply circuit in the above example. In this example, by adding an inrush current suppression circuit to the switching power supply circuit, the rectifier module BD1 can charge the electrolytic capacitor EC1 when the phase of the output DC voltage Uo is close to the 0 phase, preventing the high voltage from charging the electrolytic capacitor EC1 with a large current to form an inrush current, and there is no need to add a thermistor in the circuit to prevent the generation of inrush current, thereby reducing power loss.

[0066] The embodiments described above are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention, and should be included in the protection scope of the present invention.

Claims

1. A surge current suppression circuit, arranged between a rectifier module and an electrolytic capacitor, characterized in that: Including control chip, voltage detection module and switch module; The first end of the voltage detection module is connected to the connection node between the positive output end of the rectifier module and the first end of the electrolytic capacitor, and the second end of the voltage detection module is connected to the control chip, and is used to output a sampling voltage to the control chip according to the DC voltage output by the rectifier module; The switch module is arranged between the positive output terminal of the rectifier module and the first end of the electrolytic capacitor, or the switch module is arranged between the negative output terminal of the rectifier module and the second end of the electrolytic capacitor; The control chip is also connected to the switch module, and is used to control the switch module to be turned on when the sampled voltage is less than the reference voltage.

2. The surge current suppression circuit according to claim 1, characterized in that: The voltage detection module includes a first resistor and a second resistor; The first end of the first resistor is connected to a connection node between the positive output end of the rectifier module and the first end of the electrolytic capacitor, the second end of the first resistor is connected to the first end of the second resistor, and the second end of the second resistor is grounded; A connection node between the first resistor and the second resistor is connected to a first sampling terminal of the control chip, and is used to output a sampling voltage to the control chip.

3. The surge current suppression circuit according to claim 2, characterized in that: The voltage detection module also includes a filter capacitor; A first end of the filter capacitor is connected to a connection node between the first resistor and the second resistor, and a second end of the filter capacitor is grounded.

4. The surge current suppression circuit according to claim 1, characterized in that: The switch module includes a switch tube; The first end of the switch tube is connected to the positive output end of the rectifier module, and the second end of the switch tube is connected to the first end of the electrolytic capacitor, or the first end of the switch tube is connected to the second end of the electrolytic capacitor, and the second end of the switch tube is grounded; The third end of the switch tube is connected to the control end of the control chip and is used for being turned on or off under the control of the control chip.

5. The surge current suppression circuit according to claim 4, characterized in that: The switch module also includes a third resistor; The first end of the third resistor is connected to the second end of the switch tube, and the second end of the third resistor is connected to the third end of the switch tube.

6. The surge current suppression circuit according to claim 1, characterized in that: The surge current suppression circuit also includes a reference voltage generation module; The input end of the reference voltage generation module is connected to the input end of the rectifier module, and the output end of the reference voltage generation module is connected to the second sampling end of the control chip for outputting the reference voltage to the control chip.

7. The surge current suppression circuit according to claim 6, characterized in that: The reference voltage generation module includes a rectification unit and a voltage stabilization unit; The input end of the rectifier unit is connected to the input end of the rectifier module, and the output end of the rectifier unit is connected to the first end of the voltage stabilizing unit and the power supply end of the control chip, so as to provide a power supply voltage to the voltage stabilizing unit and the control chip; The second end of the voltage stabilizing unit is connected to the second sampling end of the control chip, and is used to output a reference voltage to the control chip.

8. The surge current suppression circuit according to claim 7, characterized in that: The voltage stabilizing unit includes a voltage stabilizing tube and a fourth resistor; The first end of the voltage regulator is connected to the output end of the rectifier unit through a fourth resistor, the second end of the voltage regulator is grounded, and the first end of the voltage regulator is connected to the control chip for clamping the voltage of the second sampling end of the control chip to a reference voltage.

9. A switching power supply circuit, characterized in that: It comprises a rectifier module, an electrolytic capacitor and the surge current suppression circuit according to any one of claims 1 to 8; The input end of the rectifier module is used to connect to the mains circuit; The positive output end of the rectifier module is connected to the first end of the electrolytic capacitor through the switch module, the second end of the electrolytic capacitor is grounded, the voltage detection module is connected to the connection node between the rectifier module and the switch module, or the positive output end of the rectifier module is connected to the voltage detection module and the first end of the electrolytic capacitor, and the second end of the electrolytic capacitor is connected to the switch module.

10. A charger, characterized in that: Includes the switching power supply circuit as claimed in claim 9.

Images