Switching power supply circuit and switching power supply equipment

Abstract

The utility model discloses a switching power supply circuit and switching power supply equipment, and the switching power supply circuit comprises a power factor correction circuit, a voltage collection circuit, a voltage detection circuit, and a main control circuit. The power factor correction circuit is arranged between the power supply input end and the voltage conversion circuit; the voltage acquisition circuit is connected with the power supply input end and is used for outputting a first voltage signal; the voltage detection circuit is connected with the voltage acquisition circuit and is used for outputting a first detection signal when the first voltage signal meets a preset condition; and the main control circuit is connected with the voltage detection circuit and the power factor correction circuit and is used for controlling the power factor correction circuit to work according to the first detection signal. According to the technical scheme, energy loss of the switching power supply circuit can be reduced.

Description

Technical Field

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

[0002] With the rapid development of science and technology, small and medium power switching power supply equipment is increasingly used in electronic products. In order to meet the increasing global requirements for the energy efficiency of electronic products, switching power supply equipment above 75W needs to meet certain harmonic requirements to ensure the stable operation of the power grid.

[0003] At present, in order to meet the harmonic requirements, switching power supply devices above 75W generally use power factor correction circuits (Power Factor Correction, referred to as PFC). The PFC circuit can effectively improve the power factor of the switching power supply device, reduce the harmonic content, and enable the switching power supply device to meet the requirements of energy efficiency certification. However, when the switching power supply device supplies power to an output load with a rated power of less than 75W, the switching power supply device does not need to meet the harmonic requirements, but the PFC circuit is still working. At this time, the switching loss of the PFC circuit causes the switching power supply device to generate a large energy loss. Utility Model Content

[0004] The embodiments of the utility model provide a switching power supply circuit and a switching power supply device to solve the problem of large energy loss when the switching power supply device supplies power to an output load with a rated power less than 75W.

[0005] A switching power supply circuit includes a power factor correction circuit, a voltage acquisition circuit, a voltage detection circuit and a main control circuit;

[0006] The power factor correction circuit is used to be arranged between the power input terminal and the voltage conversion circuit;

[0007] The voltage acquisition circuit is connected to the power input terminal and is used to output a first voltage signal;

[0008] The voltage detection circuit is connected to the voltage acquisition circuit and is used to output a first detection signal when the first voltage signal meets a preset condition;

[0009] The main control circuit is connected to the voltage detection circuit and the power factor correction circuit, and is used to control the operation of the power factor correction circuit according to the first detection signal.

[0010] Furthermore, the voltage acquisition circuit includes a first resistance circuit and a second resistance circuit; the first resistance circuit and the second resistance circuit are arranged in series between the power input terminal and the ground;

[0011] The voltage detection circuit is connected to a connection node between the first resistance circuit and the second resistance circuit.

[0012] Furthermore, the voltage detection circuit includes a first switch tube and a third resistance circuit;

[0013] The first end of the first switch tube is connected to the third resistance circuit, the second end of the first switch tube is grounded, and the third end of the first switch tube is connected to the voltage collection circuit;

[0014] The third resistance circuit is connected to the first power supply end and the main control circuit.

[0015] Furthermore, the voltage detection circuit also includes a first voltage regulator tube; the anode of the first voltage regulator tube is connected to the third end of the first switch tube, and the cathode of the first voltage regulator tube is connected to the voltage collection circuit.

[0016] Further, the third resistance circuit includes a first voltage-dividing resistor and a second voltage-dividing resistor arranged in series;

[0017] A connection node between the first voltage-dividing resistor and the second voltage-dividing resistor is connected to the main control circuit.

[0018] Furthermore, the switching power supply circuit further includes a first isolation circuit;

[0019] The first end of the first isolation circuit is connected to the connection node between the first voltage-dividing resistor and the second voltage-dividing resistor, the second end of the first isolation circuit is connected to the first end of the first switching tube; the third end of the first isolation circuit is connected to the main control circuit.

[0020] Further, the first isolation circuit includes a first optical coupler; the first optical coupler includes a first light emitting diode and a first photosensitive transistor;

[0021] The anode of the first light-emitting diode is connected to the connection node between the first voltage-dividing resistor and the second voltage-dividing resistor, and the cathode of the first light-emitting diode is connected to the first end of the first switch tube;

[0022] The first photosensitive transistor is connected to the main control circuit.

[0023] Furthermore, the switching power supply circuit further includes a second isolation circuit;

[0024] The second isolation circuit is connected to the main control circuit and the power factor correction circuit.

[0025] Furthermore, the second isolation circuit includes a second optical coupler; the second optical coupler includes a second light emitting diode and a second photosensitive transistor;

[0026] The second light emitting diode is connected to the main control circuit, and the second photosensitive transistor is connected to the power factor correction circuit.

[0027] A switching power supply device comprises the switching power supply circuit mentioned above.

[0028] The above-mentioned switching power supply circuit and switching power supply device, the switching power supply circuit includes a power factor correction circuit, a voltage acquisition circuit, a voltage detection circuit and a main control circuit; the power factor correction circuit is used to be arranged between the power input terminal and the voltage conversion circuit; the voltage acquisition circuit is connected to the power input terminal and is used to output a first voltage signal; the voltage detection circuit is connected to the voltage acquisition circuit and is used to output a first detection signal when the first voltage signal meets a preset condition; the main control circuit is connected to the voltage detection circuit and the power factor correction circuit and is used to control the power factor correction circuit to work according to the first detection signal. The voltage acquisition circuit collects the first voltage signal corresponding to the input voltage of the power input terminal, the voltage detection circuit receives the first voltage signal, and when the first voltage signal meets the preset condition, the first detection signal is output to the main control circuit, and the main control circuit can control the power factor correction circuit to stop working according to the first detection signal, thereby reducing energy loss. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] 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.

[0030] Figure 1 It is a circuit diagram of a switching power supply circuit in one embodiment of the utility model.

[0031] In the figure: 1. power factor correction circuit; 2. voltage acquisition circuit; 21. first resistance circuit; 22. second resistance circuit; 3. voltage detection circuit; 31. third resistance circuit; 4. main control circuit; 5. first isolation circuit; 6. second isolation circuit; 71. filter circuit; 72. voltage conversion circuit; 73. first switch circuit; 74. output interface circuit; 75. retrace circuit. DETAILED DESCRIPTION

[0032] 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.

[0033] 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.

[0034] 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.

[0035] 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.

[0036] 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 "a", "an" and " / the" are also intended to include plural forms, unless the context clearly indicates another way. It should also be understood that the terms "consisting of" and / or "comprising", when used in this specification, determine the presence of 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.

[0037] 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.

[0038] This embodiment provides a switching power supply circuit, such as Figure 1 As shown, it includes a power factor correction circuit 1, a voltage acquisition circuit 2, a voltage detection circuit 3 and a main control circuit 4; the power factor correction circuit 1 is used to be arranged between the power input terminal and the voltage conversion circuit 72; the voltage acquisition circuit 2 is connected to the power input terminal and is used to output a first voltage signal; the voltage detection circuit 3 is connected to the voltage acquisition circuit 2 and is used to output a first detection signal when the first voltage signal meets a preset condition; the main control circuit 4 is connected to the voltage detection circuit 3 and the power factor correction circuit 1 and is used to control the power factor correction circuit 1 to work according to the first detection signal.

[0039] As an example, the switching power supply circuit includes a filter circuit 71, a power factor correction circuit 1, a voltage conversion circuit 72, a first switch circuit 73 and an output interface circuit 74; the input end of the filter circuit 71 is used to connect to the power supply grid, and the output end of the filter circuit 71 is the power input end. The power supply grid is a municipal power grid in different countries and regions. The input end of the power factor correction circuit 1 is connected to the power input end, the output end of the power factor correction circuit 1 is connected to the input end of the voltage conversion circuit 72, and the output end of the voltage conversion circuit 72 is connected to the output interface circuit 74 through the first switch circuit 73, and the output interface circuit 74 is used to connect the output load.

[0040] Exemplarily, the voltage conversion circuit 72 includes a transformer T1A for voltage conversion. The first input end of the transformer T1A is used to connect to the power factor correction circuit 1, the second input end of the transformer T1A is used to connect to the flyback circuit 75, the first output end of the transformer T1A is connected to the VBUS end of the output interface circuit 74 through the first switch circuit 73, and the second output end of the transformer T1A is coupled to the GND end of the output interface circuit 74.

[0041] Exemplarily, the output interface circuit 74 includes a USB (Universal Serial Bus, USB for short) interface.

[0042] Exemplarily, the first switch circuit 73 includes a switch tube Q2. Optionally, the switch tube Q2 is a MOS tube. The source of the switch tube Q2 is connected to the VBUS terminal of the output interface circuit 74, the drain of the switch tube Q2 is connected to the first output terminal of the voltage conversion circuit 72, and the gate of the switch tube Q2 is used to receive a control signal. The control signal is used to control the switch tube Q2 to be turned on or off.

[0043] In this embodiment, when the switching power supply circuit is used to supply power to an output load with a relatively low rated power, such as an output load with a rated power of less than 75, if the input voltage passing through the voltage input terminal is relatively large, such as greater than 230V, and the power factor correction circuit 1 continues to work, the power factor correction circuit 1 will bring about a large switching loss, which will cause the switching power supply circuit to bring additional losses. Therefore, the first voltage signal corresponding to the input voltage at the power input terminal is collected by the voltage acquisition circuit 2, and the voltage detection circuit 3 receives the first voltage signal. When the first voltage signal meets the preset condition, the first detection signal is output to the main control circuit 4, and the main control circuit 4 can control the power factor correction circuit 1 to stop working according to the first detection signal, thereby reducing energy loss. It can be understood that the preset condition is that the input voltage corresponding to the first voltage signal is greater than the preset voltage. Preferably, the preset voltage is 230V.

[0044] In one embodiment, the voltage acquisition circuit 2 includes a first resistor circuit 21 and a second resistor circuit 22; the first resistor circuit 21 and the second resistor circuit 22 are arranged in series between the power input terminal and the ground; the voltage detection circuit 3 is connected to the connection node between the first resistor circuit 21 and the second resistor circuit 22.

[0045] As an example, the first resistance circuit 21 includes a resistor R1, a resistor R2, and a resistor R3 connected in series. The second resistance circuit 22 includes a resistor R4.

[0046] As an example, the first end of the first resistor circuit 21 is connected to the power input terminal through the first rectifier diode D1 and the second rectifier diode D2 arranged in parallel, the second end of the first resistor circuit 21 is connected to the first end of the second resistor circuit 22, and the second end of the second resistor circuit 22 is grounded. The voltage detection circuit 3 is connected to the connection node between the first resistor circuit 21 and the second resistor circuit 22. The second resistor circuit 22 is also connected in parallel with the filter capacitor C1.

[0047] In this embodiment, the first voltage signal corresponding to the input voltage of the power input terminal can be collected through the voltage division effect of the first resistor circuit 21 and the second resistor circuit 22, and the circuit structure is simple and the cost is reduced.

[0048] In one embodiment, the voltage detection circuit 3 includes a first switch tube and a third resistance circuit 31; the first end of the first switch tube is connected to the third resistance circuit 31, the second end of the first switch tube is grounded, and the third end of the first switch tube is connected to the voltage collection circuit 2; the third resistance circuit 31 is connected to the first power supply end and the main control circuit 4.

[0049] Optionally, the first switch tube may be a field effect transistor or a triode. Preferably, the first switch tube is a field effect transistor. The first end of the first switch tube is a drain, the second end of the first switch tube is a source, and the third end of the first switch tube is a gate.

[0050] As an example, when the first voltage signal output by the voltage acquisition circuit 2 is sufficient to turn on the first switch tube, a conduction path is formed between the first power supply end, the third resistor circuit 31, the first switch tube and the ground. Since the third resistor circuit 31 is connected to the main control circuit 4, the third resistor circuit 31 after being turned on can feed back an electrical signal, i.e., a first detection signal, to the main control circuit 4. After receiving the first detection signal, the main control circuit 4 controls the power factor correction circuit 1 not to work. It can be understood that the resistance value of the first resistor circuit 21, the resistance value of the second resistor circuit 22 and the first switch tube can be configured according to actual needs to ensure that when the first voltage signal meets the preset conditions, the first voltage signal can turn on the first light-opening tube.

[0051] In one embodiment, the voltage detection circuit 3 further includes a first voltage regulator tube ZD1 ; an anode of the first voltage regulator tube ZD1 is connected to the third end of the first switch tube, and a cathode of the first voltage regulator tube ZD1 is connected to the voltage collection circuit 2 .

[0052] In this embodiment, the anode of the first voltage regulator tube ZD1 is connected to the third end of the first switch tube, and the cathode of the first voltage regulator tube ZD1 is connected to the voltage collection circuit 2 to prevent the large first voltage signal from damaging the first switch tube.

[0053] Furthermore, if Figure 1As shown, the cathode of the first voltage regulator tube ZD1 is connected to the voltage collection circuit 2 via a diode D3.

[0054] Furthermore, the third terminal of the first switch tube is grounded through the capacitor C2 and the resistor R5, so as to perform filtering processing through the capacitor C2 and the resistor R5.

[0055] In one embodiment, the third resistor circuit 31 includes a first voltage-dividing resistor R7 and a second voltage-dividing resistor R6 arranged in series; a connection node between the first voltage-dividing resistor R7 and the second voltage-dividing resistor R6 is connected to the main control circuit 4 .

[0056] In this embodiment, by connecting the connection node between the first voltage-dividing resistor R7 and the second voltage-dividing resistor R6 to the main control circuit 4, when the first switch tube is turned on, the connection node between the first voltage-dividing resistor R7 and the second voltage-dividing resistor R6 can generate a first detection signal to the main control circuit 4.

[0057] In one embodiment, the switching power supply circuit also includes a first isolation circuit 5; the first end of the first isolation circuit 5 is connected to the connection node between the first voltage-dividing resistor R7 and the second voltage-dividing resistor R6, and the second end of the first isolation circuit 5 is connected to the first end of the first switching tube; the third end of the first isolation circuit 5 is connected to the main control circuit 4.

[0058] In this embodiment, the first detection signal is transmitted to the main control circuit 4 through the first isolation circuit 5 to prevent noise interference.

[0059] In one embodiment, the first isolation circuit 5 includes a first optocoupler U1; the first optocoupler U1 includes a first light-emitting diode and a first photosensitive transistor; the anode of the first light-emitting diode is connected to the connection node between the first voltage-dividing resistor R7 and the second voltage-dividing resistor R6, and the cathode of the first light-emitting diode is connected to the first end of the first switching tube; the first photosensitive transistor is connected to the main control circuit 4.

[0060] In this embodiment, when the first switch tube is turned on, the first light emitting diode is in a working state, and at this time the first photosensitive transistor is turned on, so that the main control circuit 4 receives the first detection signal.

[0061] In one embodiment, the switching power supply circuit further includes a second isolation circuit 6 ; the second isolation circuit 6 is connected to the main control circuit 4 and the power factor correction circuit 1 .

[0062] In this embodiment, the second isolation circuit 6 is connected to the main control circuit 4 and the power factor correction circuit 1 to prevent the electrical signal in the power factor correction circuit 1 from affecting the main control circuit 4 .

[0063] In one embodiment, the second isolation circuit 6 includes a second optocoupler U2 ; the second optocoupler U2 includes a second light emitting diode and a second photosensitive transistor; the second light emitting diode is connected to the main control circuit 4 , and the second photosensitive transistor is connected to the power factor correction circuit 1 .

[0064] In this embodiment, when the main control circuit 4 receives the first detection signal, it controls the second light-emitting diode to work so that the second photosensitive transistor is turned on, and the power factor correction circuit 1 can be controlled to stop working through the turn-on signal of the second photosensitive transistor, thereby reducing the switching loss of the power factor correction circuit 1.

[0065] This embodiment provides a switching power supply device, including the above-mentioned switching power supply circuit.

[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 switching power supply circuit, characterized in that: It includes a power factor correction circuit, a voltage acquisition circuit, a voltage detection circuit and a main control circuit; The power factor correction circuit is used to be arranged between the power input terminal and the voltage conversion circuit; The voltage acquisition circuit is connected to the power input terminal and is used to output a first voltage signal; The voltage detection circuit is connected to the voltage acquisition circuit and is used to output a first detection signal when the first voltage signal meets a preset condition; The main control circuit is connected to the voltage detection circuit and the power factor correction circuit, and is used to control the operation of the power factor correction circuit according to the first detection signal.

2. The switching power supply circuit according to claim 1, characterized in that: The voltage acquisition circuit comprises a first resistance circuit and a second resistance circuit; the first resistance circuit and the second resistance circuit are arranged in series between the power input terminal and the ground; The voltage detection circuit is connected to a connection node between the first resistance circuit and the second resistance circuit.

3. The switching power supply circuit according to claim 1, characterized in that: The voltage detection circuit includes a first switch tube and a third resistance circuit; The first end of the first switch tube is connected to the third resistance circuit, the second end of the first switch tube is grounded, and the third end of the first switch tube is connected to the voltage collection circuit; The third resistance circuit is connected to the first power supply end and the main control circuit.

4. The switching power supply circuit according to claim 3, characterized in that: The voltage detection circuit also includes a first voltage regulator tube; the anode of the first voltage regulator tube is connected to the third end of the first switch tube, and the cathode of the first voltage regulator tube is connected to the voltage collection circuit.

5. The switching power supply circuit according to claim 3, characterized in that: The third resistor circuit includes a first voltage-dividing resistor and a second voltage-dividing resistor arranged in series; A connection node between the first voltage-dividing resistor and the second voltage-dividing resistor is connected to the main control circuit.

6. The switching power supply circuit according to claim 5, characterized in that: The switching power supply circuit also includes a first isolation circuit; The first end of the first isolation circuit is connected to the connection node between the first voltage-dividing resistor and the second voltage-dividing resistor, the second end of the first isolation circuit is connected to the first end of the first switching tube; the third end of the first isolation circuit is connected to the main control circuit.

7. The switching power supply circuit according to claim 6, characterized in that: The first isolation circuit includes a first optical coupler; the first optical coupler includes a first light emitting diode and a first photosensitive transistor; The anode of the first light-emitting diode is connected to the connection node between the first voltage-dividing resistor and the second voltage-dividing resistor, and the cathode of the first light-emitting diode is connected to the first end of the first switch tube; The first photosensitive transistor is connected to the main control circuit.

8. The switching power supply circuit according to claim 1, characterized in that: The switching power supply circuit also includes a second isolation circuit; The second isolation circuit is connected to the main control circuit and the power factor correction circuit.

9. The switching power supply circuit according to claim 8, characterized in that: The second isolation circuit includes a second optical coupler; the second optical coupler includes a second light emitting diode and a second photosensitive transistor; The second light emitting diode is connected to the main control circuit, and the second photosensitive transistor is connected to the power factor correction circuit.

10. A switching power supply device, characterized in that: A switching power supply circuit comprising any one of claims 1 to 9.

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