Surge suppression circuit, switching power supply circuit and charger

Abstract

This utility model discloses a surge suppression circuit, a switching power supply circuit, and a charger. The surge suppression circuit includes a voltage conversion circuit, a first capacitor circuit, a second capacitor circuit, an anti-backflow circuit, a first switching circuit, and a main control circuit. By setting the capacitance value of the first capacitor circuit to be greater than that of the second capacitor circuit, the second capacitor circuit is charged before its capacitor voltage exceeds a first preset voltage. When the capacitor voltage of the second capacitor circuit exceeds the first preset voltage and the voltage phase corresponding to the AC voltage is at a zero-crossing point, the first switching circuit is controlled to conduct, charging the first capacitor circuit. This replaces the surge suppression method of PTC thermistor plus relay, achieving surge suppression and reducing the space occupied by the surge suppression circuit.

Description

Technical Field

[0001] This utility model relates to the field of switching power supply technology, and in particular to a surge suppression circuit, a switching power supply circuit, and a charger. Background Technology

[0002] With the increasing power density of server power supplies, the inrush current generated by the large capacitor charging in the PFC (Power Factor Correction) circuit during startup is becoming increasingly serious, potentially damaging components and affecting the power grid. Current technologies generally employ a PTC thermistor plus relay solution to suppress surges, such as using a PTC thermistor and relay in parallel; the PTC limits the current during startup, and the relay conducts after stabilization. While this solution can suppress surges, it has significant drawbacks, such as large space requirements, poor relay reliability, slow response of thermistors, and high cost, thus hindering the improvement of power density. Utility Model Content

[0003] This utility model provides a surge suppression circuit, a switching power supply circuit, and a charger to solve the problem of large space occupation of existing surge suppression circuits.

[0004] A surge suppression circuit includes a voltage conversion circuit, a first capacitor circuit, a second capacitor circuit, an anti-backflow circuit, a first switching circuit, and a main control circuit. The input terminal of the voltage conversion circuit is used to connect to the voltage input terminal, and the output terminal of the voltage conversion circuit is used to connect to the voltage output terminal, for converting the AC voltage input to the voltage input terminal and outputting DC voltage to the voltage output terminal; The first capacitor circuit and the first switch circuit are connected in series between the output terminal of the voltage conversion circuit and ground; The first terminal of the anti-backflow circuit is connected to the output terminal of the voltage conversion circuit, the second terminal of the anti-backflow circuit is connected to the first terminal of the second capacitor circuit, and the second terminal of the second capacitor circuit is grounded. The main control circuit is connected to the first switching circuit and is used to control the first switching circuit to conduct when the capacitor voltage of the second capacitor circuit is greater than the first preset voltage and the voltage phase corresponding to the AC voltage is at a zero crossing point.

[0005] Furthermore, the voltage conversion circuit includes a rectifier circuit and a boost circuit; The rectifier circuit is connected to the voltage input terminal and is used to convert the AC voltage into a DC rectified voltage. The boost circuit is connected to the rectifier circuit and is used to boost the DC rectified voltage to output the DC voltage.

[0006] Furthermore, the boost circuit includes a first inductor, a first diode, and a second switching circuit; The first end of the first inductor is connected to the rectifier circuit, the second end of the first inductor is connected to the anode of the first diode, and the cathode of the first diode is the output terminal of the voltage conversion circuit. The first terminal of the second switching circuit is connected to the second terminal of the first inductor and the anode of the first diode. The second terminal of the second switching circuit is grounded. The control terminal of the second switching circuit is connected to the main control circuit.

[0007] Furthermore, the surge suppression circuit also includes a second diode; The anode of the second diode is connected to the first terminal of the first inductor, and the cathode of the second diode is connected to the cathode of the first diode.

[0008] Furthermore, the capacitance value exhibited by the first capacitor circuit is greater than the capacitance value exhibited by the second capacitor circuit.

[0009] Furthermore, the anti-backflow circuit includes a third diode.

[0010] Furthermore, the first switching circuit includes a first switching transistor; The first terminal of the first capacitor circuit is connected to the output terminal of the voltage conversion circuit, the second terminal of the first capacitor circuit is connected to the first terminal of the first switching transistor, the second terminal of the first switching transistor is grounded, and the third terminal of the first switching transistor is connected to the main control circuit.

[0011] Furthermore, the surge suppression circuit also includes a third capacitor circuit; The first terminal of the third capacitor circuit is connected to the third terminal of the first switching transistor, and the second terminal of the third capacitor circuit is grounded.

[0012] Furthermore, the surge suppression circuit also includes a first voltage divider circuit; the first terminal of the first voltage divider circuit is connected to the main control circuit, the second terminal of the first voltage divider circuit is grounded, and the third terminal of the first voltage divider circuit is connected to the third terminal of the first switching transistor.

[0013] A switching power supply circuit includes the surge suppression circuit described above.

[0014] A charger comprising the aforementioned switching power supply circuit.

[0015] This utility model provides a surge suppression circuit, a switching power supply circuit, and a charger. The surge suppression circuit includes a voltage conversion circuit, a first capacitor circuit, a second capacitor circuit, an anti-backflow circuit, a first switching circuit, and a main control circuit. By setting the capacitance value of the first capacitor circuit to be greater than that of the second capacitor circuit, the second capacitor circuit is charged before its voltage exceeds a first preset voltage. When the voltage of the second capacitor circuit exceeds the first preset voltage and the phase of the AC voltage is at a zero-crossing point, the first switching circuit is turned on to charge the first capacitor circuit. This replaces the surge suppression method of using a PTC thermistor and relay, achieving surge suppression and reducing the space occupied by the surge suppression circuit. Attached Figure Description

[0016] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the description of the embodiments of this utility model 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.

[0017] Figure 1 This is a schematic diagram of a surge suppression circuit in one embodiment of the present invention.

[0018] In the diagram: 11. Voltage conversion circuit; 111. Rectifier circuit; 112. Boost circuit; 1121. Second switching circuit; 12. First capacitor circuit; 13. Second capacitor circuit; 14. Anti-backflow circuit; 15. First switching circuit; 16. Third capacitor circuit; 17. First voltage divider circuit. Detailed Implementation

[0019] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present utility model.

[0020] It should be understood that this invention can be embodied in various forms and should not be construed as being limited to the embodiments set forth herein. Rather, providing these embodiments will make the disclosure thorough and complete, and will fully convey the scope of this invention to those skilled in the art.

[0021] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of the invention. When used herein, the singular forms “a,” “an,” and “ / the” are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms “comprising” and / or “comprising,” when used in this specification, identify the presence of features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups. When used herein, the term “and / or” includes any and all combinations of the associated listed items.

[0022] To fully understand this utility model, detailed structures and steps will be presented in the following description to illustrate the technical solution proposed by this utility model. Preferred embodiments of this utility model are described in detail below; however, in addition to these detailed descriptions, this utility model may have other embodiments.

[0023] This embodiment provides a surge suppression circuit, such as Figure 1 As shown, the circuit includes a voltage conversion circuit 11, a first capacitor circuit 12, a second capacitor circuit 13, an anti-backflow circuit 14, a first switch circuit 15, and a main control circuit (not shown in the figure). The capacitance value of the first capacitor circuit 12 is greater than that of the second capacitor circuit 13. The input terminal of the voltage conversion circuit 11 is connected to the voltage input terminal, and the output terminal of the voltage conversion circuit 11 is connected to the voltage output terminal. It is used to convert the AC voltage input to the voltage input terminal and output DC voltage to the voltage output terminal. The first capacitor circuit 12 and the first switch circuit 15 are connected in series between the output terminal of the voltage conversion circuit 11 and ground. The first terminal of the anti-backflow circuit 14 is connected to the output terminal of the voltage conversion circuit 11, and the second terminal of the anti-backflow circuit 14 is connected to the first terminal of the second capacitor circuit 13. The second terminal of the second capacitor circuit 13 is grounded. The main control circuit is connected to the first switch circuit 15 and is used to control the first switch circuit 15 to conduct when the capacitor voltage B+AUX of the second capacitor circuit 13 is greater than a first preset voltage and the voltage phase corresponding to the AC voltage is at a zero crossing point.

[0024] As an example, the input terminal of the voltage conversion circuit 11 is connected to a voltage input terminal, and the output terminal of the voltage conversion circuit 11 is connected to a voltage output terminal. It is used to convert the AC voltage input at the voltage input terminal to a DC voltage output at the voltage output terminal. Exemplarily, the voltage input terminal is connected to an AC power source. Optionally, the AC power source can be the mains grid. The voltage conversion circuit 11 performs DC-DC conversion and boosting processing on the AC voltage provided by the AC power source, outputting a DC voltage. The voltage output terminal is used to connect to an electrical load.

[0025] As an example, the first capacitor circuit 12 and the first switching circuit 15 are connected in series between the output terminal of the voltage conversion circuit 11 and ground. Exemplarily, the first capacitor circuit 12 includes a first capacitor C1. The number of first capacitors C1 can be set according to actual needs. Multiple first capacitors C1 can be connected in series and / or in parallel.

[0026] As an example, the first terminal of the anti-backflow circuit 14 is connected to the output terminal of the voltage conversion circuit 11, and the second terminal of the anti-backflow circuit 14 is connected to the first terminal of the second capacitor circuit 13, the second terminal of the second capacitor circuit 13 being grounded. In this example, the anti-backflow circuit 14 is used to prevent the energy stored in the second capacitor circuit 13 from flowing back into the first capacitor circuit 12. Exemplarily, the second capacitor circuit 13 includes a second capacitor C2. The number of the second capacitors C2 can be set according to actual needs. Multiple second capacitors C2 can be connected in series and / or in parallel.

[0027] As an example, the first capacitor circuit 12 includes a first capacitor C1, and the second capacitor circuit 13 includes a second capacitor C2. Preferably, the second capacitor C2 is a surface-mount capacitor, such as a surface-mount ceramic capacitor, to further reduce space occupation. As an example, the first capacitor C1 is an electrolytic capacitor, and the second capacitor C2 is disposed adjacent to the first capacitor C1, so that the second capacitor C2 can be disposed on the bottom periphery of the first capacitor C1, which has a larger capacitance value, to make full use of space.

[0028] As an example, the main control circuit is connected to the first switching circuit 15 and is used to control the first switching circuit 15 to conduct when the capacitor voltage B+AUX of the second capacitor circuit 13 is greater than a first preset voltage and the voltage phase corresponding to the AC voltage is at a zero crossing point. The first preset voltage is a pre-configured voltage value.

[0029] For example, the AC voltage is an AC sinusoidal waveform. The magnitude of the surge current in the surge suppression circuit is related to the initial phase of the AC voltage. If the voltage phase when the AC voltage is input to the power supply input terminal is exactly 90 degrees, that is, the peak position of the AC sine wave, the surge current is the largest when charging the large capacitor. If the voltage phase when the AC voltage is input to the power supply input terminal is close to 0 degrees, that is, when it is at the zero crossing point, the surge current is the smallest when charging the large capacitor.

[0030] In this example, when AC voltage is input, regardless of whether the AC voltage phase is at a peak or zero-crossing point, the voltage conversion circuit 11 charges the second capacitor circuit 13 with a smaller capacitance value using the converted DC voltage. At this time, the main control circuit controls the first switch circuit 15 to open, and the first capacitor circuit 12 does not charge. Because the capacitance value of the second capacitor circuit 13 is small, the surge current is small. When the second capacitor circuit 13 is fully charged, the capacitor voltage B+AUX of the second capacitor circuit 13 is greater than the first preset voltage. The main control circuit starts working, detecting the voltage phase corresponding to the AC voltage. When the voltage phase corresponding to the AC voltage is at a zero-crossing point, the first switch circuit 15 is controlled to turn on, so that when the AC voltage before voltage conversion is close to 0V, the first capacitor circuit 12 with a larger capacitance value is charged by the converted DC voltage, thereby ensuring that the surge current is small when the first capacitor circuit 12 is charging, achieving surge suppression.

[0031] Furthermore, the surge suppression circuit includes an auxiliary power supply circuit. When the capacitor voltage B+AUX of the second capacitor circuit 13 is greater than the first preset voltage, the auxiliary power supply circuit generates a supply voltage to power the main control circuit, thereby enabling the main control circuit to start working. Understandably, when the voltage phase corresponding to the AC voltage is at a zero-crossing point, that is, during the charging process of the first capacitor circuit 12 with a larger capacitance value by the DC voltage, the amount of electricity stored in the second capacitor circuit 13 is sufficient to provide energy to the auxiliary power supply circuit, preventing the main control circuit from being powered off. For example, the main control circuit includes a DPS (Digital Power System) chip.

[0032] In this embodiment, the surge suppression circuit includes a voltage conversion circuit 11, a first capacitor circuit 12, a second capacitor circuit 13, an anti-backflow circuit 14, a first switch circuit 15, and a main control circuit. By setting the capacitance value of the first capacitor circuit 12 to be greater than that of the second capacitor circuit 13, the second capacitor circuit 13 is charged before its capacitor voltage B+AUX exceeds a first preset voltage. When the capacitor voltage B+AUX of the second capacitor circuit 13 exceeds the first preset voltage and the voltage phase corresponding to the AC voltage is at a zero-crossing point, the first switch circuit 15 is controlled to conduct, charging the first capacitor circuit 12. This replaces the surge suppression method of PTC thermistor plus relay, achieving surge suppression and reducing the space occupied by the surge suppression circuit.

[0033] In one embodiment, the voltage conversion circuit 11 includes a rectifier circuit 111 and a boost circuit 112; the rectifier circuit 111 is connected to the voltage input terminal and is used to convert AC voltage into DC rectified voltage; the boost circuit 112 is connected to the rectifier circuit 111 and is used to boost the DC rectified voltage to output DC voltage.

[0034] In this embodiment, the rectifier circuit 111 includes a bridge rectifier diode for converting AC voltage into DC rectified voltage. Then, the DC rectified voltage is boosted by the boost circuit 112 to output DC voltage, so as to obtain a DC voltage that meets the power demand of the electrical load.

[0035] In one embodiment, the boost circuit 112 includes a first inductor L1, a first diode D1, and a second switching circuit 1121. The first end of the first inductor L1 is connected to the rectifier circuit 111, the second end of the first inductor L1 is connected to the anode of the first diode D1, and the cathode of the first diode D1 is the output terminal of the voltage conversion circuit 11. The first end of the second switching circuit 1121 is connected to the second end of the first inductor L1 and the anode of the first diode D1, the second end of the second switching circuit 1121 is grounded, and the control terminal of the second switching circuit 1121 is connected to the main control circuit.

[0036] As an example, the second switching circuit 1121 includes a second switching transistor Q2, which may optionally be a MOSFET or an IGBT. Exemplarily, the second switching transistor Q2 is a MOSFET, the drain of the second switching transistor Q2 is connected to the second terminal of the first inductor L1 and the anode of the first diode D1, the source of the second switching transistor Q2 is grounded, and the gate of the second switching transistor Q2 is connected to the main control circuit.

[0037] In this embodiment, the main control circuit controls the second switching circuit 1121 to conduct alternately. Utilizing the energy storage characteristics of the first inductor L1, the first switching circuit 15 controls the periodic switching on and off. When the first inductor L1 is on, it stores energy. When it is off, the energy of the first inductor L1 is superimposed with the DC rectified voltage and output through the first diode D1, thereby realizing the boosting of the DC rectified voltage and outputting a DC voltage. The circuit structure is simple and the cost is low.

[0038] In one embodiment, the surge suppression circuit further includes a second diode D2; the anode of the second diode D2 is connected to the first terminal of the first inductor L1, and the cathode of the second diode D2 is connected to the cathode of the first diode D1.

[0039] In this embodiment, the anode of the second diode D2 is connected to the first terminal of the first inductor L1, and the cathode of the second diode D2 is connected to the cathode of the first diode D1. This forms a surge current path and protects the second switching transistor Q2 when lightning strikes the power input terminal, thereby improving the safety of the circuit.

[0040] In one embodiment, the backflow prevention circuit 14 includes a third diode D3. In this embodiment, backflow prevention is achieved by using the third diode D3, that is, preventing the energy stored in the second capacitor circuit 13 from flowing back into the first capacitor circuit 12. The circuit structure is simple and the cost is low.

[0041] In one embodiment, the first switching circuit 15 includes a first switching transistor Q1; the first terminal of the first capacitor circuit 12 is connected to the output terminal of the voltage conversion circuit 11, the second terminal of the first capacitor C1 is connected to the first terminal of the first switching transistor Q1, the second terminal of the first switching transistor Q1 is grounded, and the third terminal of the first switching transistor Q1 is connected to the main control circuit.

[0042] For example, the first switching transistor Q1 is a MOSFET or an IGBT. For example, the first switching transistor Q1 is a MOSFET, the first terminal of the first switching transistor Q1 is the drain, the second terminal of the first switching transistor Q1 is the source, and the third terminal of the first switching transistor Q1 is the gate.

[0043] In this example, when the capacitor voltage B+AUX of the second capacitor circuit 13 is greater than the first preset voltage and the voltage phase corresponding to the AC voltage is at the zero crossing point, the main control circuit outputs a high-level signal to control the first switching transistor Q1 to turn on, and the second voltage charges the first capacitor circuit 12, thereby replacing the surge suppression method of PTC thermistor plus relay, realizing surge suppression and reducing the space occupied by the surge suppression circuit.

[0044] In one embodiment, the surge suppression circuit further includes a third capacitor circuit 16; the first terminal of the third capacitor circuit 16 is connected to the third terminal of the first switching transistor Q1, and the second terminal of the third capacitor circuit 16 is grounded.

[0045] As an example, the third capacitor circuit 16 includes a third capacitor C3. The number of third capacitors C3 can be set according to practical experience. Multiple first capacitors C1 can be connected in series and / or in parallel.

[0046] In this embodiment, the first terminal of the third capacitor circuit 16 is connected to the third terminal of the first switching transistor Q1, and the second terminal of the third capacitor circuit 16 is grounded. Therefore, the turn-on speed of the first switching transistor Q1 can be adjusted by configuring the capacitance value of the third capacitor circuit 16. For example, the larger the capacitance value of the third capacitor circuit 16, the slower the turn-on speed of the first switching transistor Q1, and the smaller the charging current to the first capacitor circuit 12, which is equivalent to a smaller inrush current. Conversely, the smaller the capacitance value of the third capacitor circuit 16, the faster the turn-on speed of the first switching transistor Q1, and the larger the charging current to the first capacitor circuit 12, which is equivalent to a larger inrush current.

[0047] In one embodiment, the surge suppression circuit further includes a first voltage divider circuit 17; the first terminal of the first voltage divider circuit 17 is connected to the main control circuit, the second terminal of the first voltage divider circuit 17 is grounded, and the third terminal of the first voltage divider circuit 17 is connected to the third terminal of the first switching transistor Q1.

[0048] For example, the first voltage divider circuit 17 includes a first resistor R1 and a second resistor R2. The first end of the first resistor R1 is connected to the main control circuit, the second end of the first resistor R1 is connected to the first end of the second resistor R2, the second end of the second resistor R2 is grounded, and the connection node between the first resistor R1 and the second resistor R2 is connected to the third end of the first switching transistor Q1.

[0049] In this example, the first terminal of the first voltage divider circuit 17 is connected to the main control circuit, the second terminal of the first voltage divider circuit 17 is grounded, and the third terminal of the first voltage divider circuit 17 is connected to the third terminal of the first switching transistor Q1. This allows the main control circuit to drive the first switching transistor Q1 to work through the first voltage divider circuit 17, preventing the gate oxide layer of the first switching transistor Q1 from being broken down and ensuring the safety of the first switching transistor Q1.

[0050] This embodiment provides a switching power supply circuit, including the surge suppression circuit described above.

[0051] This embodiment provides a charger, including the switching power supply circuit described above.

[0052] The above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this utility model, and should all be included within the protection scope of this utility model.

Claims

1. A surge suppression circuit, characterized in that, It includes a voltage conversion circuit, a first capacitor circuit, a second capacitor circuit, an anti-backflow circuit, a first switching circuit, and a main control circuit; the capacitance value of the first capacitor circuit is greater than the capacitance value of the second capacitor circuit. The input terminal of the voltage conversion circuit is used to connect to the voltage input terminal, and the output terminal of the voltage conversion circuit is used to connect to the voltage output terminal, for converting the AC voltage input to the voltage input terminal and outputting DC voltage to the voltage output terminal; The first capacitor circuit and the first switch circuit are connected in series between the output terminal of the voltage conversion circuit and ground; The first terminal of the anti-backflow circuit is connected to the output terminal of the voltage conversion circuit, the second terminal of the anti-backflow circuit is connected to the first terminal of the second capacitor circuit, and the second terminal of the second capacitor circuit is grounded. The main control circuit is connected to the first switching circuit and is used to control the first switching circuit to conduct when the capacitor voltage of the second capacitor circuit is greater than the first preset voltage and the voltage phase corresponding to the AC voltage is at a zero crossing point.

2. The surge suppression circuit according to claim 1, characterized in that, The voltage conversion circuit includes a rectifier circuit and a boost circuit; The rectifier circuit is connected to the voltage input terminal and is used to convert the AC voltage into a DC rectified voltage. The boost circuit is connected to the rectifier circuit and is used to boost the DC rectified voltage to output the DC voltage.

3. The surge suppression circuit according to claim 2, characterized in that, The boost circuit includes a first inductor, a first diode, and a second switching circuit. The first end of the first inductor is connected to the rectifier circuit, the second end of the first inductor is connected to the anode of the first diode, and the cathode of the first diode is the output terminal of the voltage conversion circuit. The first terminal of the second switching circuit is connected to the second terminal of the first inductor and the anode of the first diode. The second terminal of the second switching circuit is grounded. The control terminal of the second switching circuit is connected to the main control circuit.

4. The surge suppression circuit according to claim 3, characterized in that, The surge suppression circuit also includes a second diode; The anode of the second diode is connected to the first terminal of the first inductor, and the cathode of the second diode is connected to the cathode of the first diode.

5. The surge suppression circuit according to claim 1, characterized in that, The backflow prevention circuit includes a third diode.

6. The surge suppression circuit according to claim 1, characterized in that, The first switching circuit includes a first switching transistor; The first terminal of the first capacitor circuit is connected to the output terminal of the voltage conversion circuit, the second terminal of the first capacitor circuit is connected to the first terminal of the first switching transistor, the second terminal of the first switching transistor is grounded, and the third terminal of the first switching transistor is connected to the main control circuit.

7. The surge suppression circuit according to claim 6, characterized in that, The surge suppression circuit also includes a third capacitor circuit; The first terminal of the third capacitor circuit is connected to the third terminal of the first switching transistor, and the second terminal of the third capacitor circuit is grounded.

8. The surge suppression circuit as described in claim 6, characterized in that, The surge suppression circuit further includes a first voltage divider circuit; the first terminal of the first voltage divider circuit is connected to the main control circuit, the second terminal of the first voltage divider circuit is grounded, and the third terminal of the first voltage divider circuit is connected to the third terminal of the first switching transistor.

9. A switching power supply circuit, characterized in that, Includes the surge suppression circuit as described in any one of claims 1 to 8.

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

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