Power supply circuit and power supply device

Abstract

The application discloses a power supply circuit and device, and belongs to the technical field of circuits. The power supply circuit comprises a transformer T and a switching circuit. The transformer T comprises a primary winding, a first secondary winding and a second secondary winding. The first secondary winding comprises a secondary winding N1 and a secondary winding N2 connected in series. The second secondary winding comprises a secondary winding N3 and a secondary winding N4 connected in series. When the mains voltage changes, the power supply circuit changes the connection mode between the first secondary winding and the second secondary winding of the transformer T through the switching circuit, so that the voltage output from the power supply circuit to the load circuit remains unchanged. Therefore, the power supply circuit can keep the voltage output from the power supply circuit to the load circuit unchanged without adjusting the duty cycle of the transformer T, so that the efficiency of the power supply circuit output power can be improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of circuit, in particular to a power supply circuit and a power supply device. BACKGROUND

[0002] With the rapid development of science and technology, the relationship between power equipment and human life is also becoming closer and closer. The mains supplies power to the power equipment through the transformer, and the voltage of the mains generally includes 110 volts and 220 volts.

[0003] In the related art, when the mains voltage is switched between 110 volts and 220 volts, the duty cycle of the transformer is usually adjusted to keep the voltage output by the transformer unchanged.

[0004] However, adjusting the duty cycle of the transformer will affect the working state of the transformer, which is not conducive to the efficient output of electric energy by the transformer.

[0005] TECHNICAL PROBLEM

[0006] The embodiments of the present application provide a power supply circuit and a power supply device, which can keep the voltage output by the power supply circuit unchanged by changing the connection mode between the first secondary winding and the second secondary winding of the transformer T through the switching circuit, on the premise that the duty cycle of the transformer T is unchanged.

[0007] TECHNICAL SOLUTION

[0008] In a first aspect, a power supply circuit is provided, comprising: a transformer T and a switching circuit, the transformer T comprising a primary winding, a first secondary winding and a second secondary winding;

[0009] The first secondary winding comprises a secondary winding N1 and a secondary winding N2 connected in series, and the second secondary winding comprises a secondary winding N3 and a secondary winding N4 connected in series;

[0010] The switching circuit is connected between the first secondary winding and a load circuit, and the switching circuit is connected between the second secondary winding and the load circuit;

[0011] When the primary winding inputs a first voltage, the secondary winding N1 and the secondary winding N4 are connected in series through the switching circuit, and the secondary winding N2 and the secondary winding N3 are connected in series through the switching circuit, to supply power to the load circuit;

[0012] When the primary winding inputs a second voltage, the secondary winding N1 and the secondary winding N4 are connected in parallel through the switching circuit, and the secondary winding N2 and the secondary winding N3 are connected in parallel through the switching circuit, to supply power to the load circuit.

[0013] Optionally, the first auxiliary winding comprises a first end, a second end and a third end, the first end of the auxiliary winding N1 is the first end of the first auxiliary winding, the second end of the auxiliary winding N1 is connected with the first end of the auxiliary winding N2, and the second end of the auxiliary winding N1 and the first end of the auxiliary winding N2 constitute the second end of the first auxiliary winding, the second end of the auxiliary winding N2 is the third end of the first auxiliary winding; the switching circuit is connected between the second end of the first auxiliary winding and the load circuit; the first end and the third end of the first auxiliary winding are connected with the input end of the load circuit.

[0014] The second auxiliary winding comprises a first end, a second end and a third end, the first end of the auxiliary winding N3 is the first end of the second auxiliary winding, the second end of the auxiliary winding N3 is connected with the first end of the auxiliary winding N4, and the second end of the auxiliary winding N3 and the first end of the auxiliary winding N4 constitute the second end of the second auxiliary winding, the second end of the auxiliary winding N4 is the third end of the second auxiliary winding; the switching circuit is connected between the second end of the second auxiliary winding and the load circuit; the first end and the third end of the second auxiliary winding are connected with the output end of the load circuit.

[0015] Optionally, the power supply circuit further comprises a first rectifier circuit and a second rectifier circuit.

[0016] The first end of the first rectifier circuit is connected with the first end of the first auxiliary winding, and the second end of the first rectifier circuit is connected with the third end of the first auxiliary winding; the third end of the first rectifier circuit is connected with the input end of the load circuit.

[0017] The first end of the second rectifier circuit is connected with the output end of the load circuit; the second end of the second rectifier circuit is connected with the first end of the second auxiliary winding, and the third end of the second rectifier circuit is connected with the third end of the second auxiliary winding.

[0018] Optionally, the first rectifier circuit comprises a diode D1 and a diode D2; the second rectifier circuit comprises a diode D3 and a diode D4.

[0019] The anode of the diode D1 is connected with the first end of the first auxiliary winding, and the cathode of the diode D1 is connected with the input end of the load circuit.

[0020] The anode of the diode D2 is connected with the third end of the first auxiliary winding, and the cathode of the diode D1 is connected with the input end of the load circuit.

[0021] An anode of the diode D3 is connected with an output end of the load circuit, and a cathode of the diode D3 is connected with a first end of the second secondary winding;

[0022] An anode of the diode D4 is connected with the output end of the load circuit, and a cathode of the diode D4 is connected with a third end of the second secondary winding.

[0023] Optionally, the switching circuit has a first end, a second end, a third end and a fourth end;

[0024] The first end of the switching circuit is connected with the second end of the first secondary winding, the second end of the switching circuit is connected with the second end of the second secondary winding, the third end of the switching circuit is connected with the input end of the load circuit, and the fourth end of the switching circuit is connected with the output end of the load circuit.

[0025] Optionally, the switching circuit comprises a switching device K1 and a switching device K2;

[0026] The switching device K1 comprises a first contact, a second contact and a third contact, the first contact of the switching device K1 is connected with the second end of the first secondary winding, the second contact of the switching device K1 is connected with the output end of the load circuit, and the third contact of the switching device K1 is connected with the second end of the second secondary winding;

[0027] The switching device K2 comprises a first contact, a second contact and a third contact, the first contact of the switching device K2 is connected with the second end of the second secondary winding, the second contact of the switching device K2 is connected with the input end of the load circuit, and the third contact of the switching device K2 is connected with the second end of the first secondary winding;

[0028] When the first contact of the switching device K1 and the second contact of the switching device K1 are connected, and the first contact of the switching device K2 and the second contact of the switching device K2 are connected, the secondary winding N1 and the secondary winding N4 are connected in parallel, and the secondary winding N2 and the secondary winding N3 are connected in parallel; when the first contact of the switching device K1 and the third contact of the switching device K1 are connected, and the first contact of the switching device K2 and the third contact of the switching device K2 are connected, the secondary winding N1 and the secondary winding N4 are connected in series, and the secondary winding N2 and the secondary winding N3 are connected in series.

[0029] Optionally, the switching circuit comprises a transistor VT1, a diode D5, a diode D6 and a diode D7;

[0030] The transistor VT1 has a control terminal, a first terminal and a second terminal, the first terminal of the transistor VT1 is connected with the second terminal of the first secondary winding, and the second terminal of the transistor VT1 is connected with the second terminal of the second secondary winding;

[0031] The anode of the diode D5 is connected with the second terminal of the transistor VT1, and the cathode of the diode D5 is connected with the input terminal of the load circuit;

[0032] The anode of the diode D6 is connected with the output terminal of the load circuit, and the cathode of the diode D6 is connected with the first terminal of the transistor VT1;

[0033] The anode of the diode D7 is connected with the first terminal of the transistor VT1, and the cathode of the diode D7 is connected with the second terminal of the transistor VT1;

[0034] When the first terminal of the transistor VT1 is connected with the second terminal of the transistor VT1, the secondary winding N1 and the secondary winding N4 are connected in series, and the secondary winding N2 and the secondary winding N3 are connected in series; when the first terminal of the transistor VT1 is disconnected with the second terminal of the transistor VT1, the secondary winding N1 and the secondary winding N4 are connected in parallel, and the secondary winding N2 and the secondary winding N3 are connected in parallel.

[0035] Optionally, the power supply circuit further comprises a third rectifier circuit;

[0036] The third rectifier circuit has a first terminal, a second terminal and a third terminal; the first terminal of the third rectifier circuit is connected with the first terminal of the first secondary winding, and the first terminal of the third rectifier circuit is connected with the third terminal of the first secondary winding; the second terminal of the third rectifier circuit is connected with the input terminal of the load circuit; the third terminal of the third rectifier circuit is connected with the output terminal of the load circuit, and the third terminal of the third rectifier circuit is connected with the first terminal of the second secondary winding and the third terminal of the second secondary winding.

[0037] Optionally, the third rectifier circuit comprises an inductor L1 and a capacitor C1;

[0038] The first terminal of the inductor L1 is connected with the first terminal of the first secondary winding, and the first terminal of the inductor L1 is connected with the third terminal of the first secondary winding; the second terminal of the inductor L1 is connected with the input terminal of the load circuit;

[0039] The first plate of the capacitor C1 is connected with the second terminal of the inductor L1, the second plate of the capacitor C1 is connected with the output terminal of the load circuit, and the second plate of the capacitor C1 is connected with the first terminal of the second secondary winding and the third terminal of the second secondary winding.

[0040] In a second aspect, a power supply device is provided, comprising the power supply circuit according to the first aspect.

[0041] Advantages

[0042] In the present application, the power supply circuit comprises a transformer T and a switching circuit. The transformer T comprises a primary winding, a first secondary winding and a second secondary winding. The first secondary winding comprises a secondary winding N1 and a secondary winding N2 connected in series, and the second secondary winding comprises a secondary winding N3 and a secondary winding N4 connected in series. The switching circuit is connected between the first secondary winding and the load circuit, and is also connected between the second secondary winding and the load circuit. The primary winding can be connected to the mains. When the mains voltage is a first voltage of 110V, the secondary winding N1 and the secondary winding N4 are connected in series through the switching circuit to supply power to the load circuit in a first half cycle of the first voltage; and the secondary winding N2 and the secondary winding N3 are connected in series through the switching circuit to supply power to the load circuit in a second half cycle of the first voltage. When the mains voltage is a second voltage of 220V, the secondary winding N1 and the secondary winding N4 are connected in parallel through the switching circuit to supply power to the load circuit in a first half cycle of the second voltage; and the secondary winding N2 and the secondary winding N3 are connected in parallel through the switching circuit to supply power to the load circuit in a second half cycle of the second voltage. When the mains voltage changes, the power supply circuit can change the connection mode between the first secondary winding and the second secondary winding of the transformer T through the switching circuit, so that the voltage output to the load circuit by the power supply circuit remains unchanged. Therefore, the power supply circuit does not need to adjust the duty cycle of the transformer T to keep the voltage output to the load circuit unchanged, thereby improving the efficiency of the power supply circuit in outputting electric energy. BRIEF DESCRIPTION OF DRAWINGS

[0043] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative effort.

[0044] Figure 1 is a structural schematic diagram of a first power supply circuit provided by the embodiments of the present application;

[0045] Figure 2 is a structural schematic diagram of a second power supply circuit provided by the embodiments of the present application;

[0046] Figure 3 is a structural schematic diagram of a first switching circuit provided by the embodiments of the present application;

[0047] Figure 4is a structural schematic diagram of a third power supply circuit provided by the embodiment of the present application;

[0048] Figure 5 is a structural schematic diagram of the power supply circuit when a first voltage is inputted according to an embodiment of the present application;

[0049] Figure 6 is an equivalent circuit diagram of the first power supply circuit when a first voltage is inputted according to an embodiment of the present application;

[0050] Figure 7 is a structural schematic diagram of the power supply circuit when a second voltage is inputted according to an embodiment of the present application;

[0051] Figure 8 is an equivalent circuit diagram of the first power supply circuit when a second voltage is inputted according to an embodiment of the present application;

[0052] Figure 9 is an equivalent circuit diagram of the second power supply circuit when a second voltage is inputted according to an embodiment of the present application;

[0053] Figure 10 is a structural schematic diagram of a second switching circuit according to an embodiment of the present application;

[0054] Figure 11 is a structural schematic diagram of a fourth power supply circuit according to an embodiment of the present application;

[0055] Figure 12 is an equivalent circuit diagram of the second power supply circuit when a first voltage is inputted according to an embodiment of the present application;

[0056] Figure 13 is an equivalent circuit diagram of the third power supply circuit when a second voltage is inputted according to an embodiment of the present application;

[0057] Figure 14 is an equivalent circuit diagram of the fourth power supply circuit when a second voltage is inputted according to an embodiment of the present application;

[0058] Figure 15 is a structural schematic diagram of a fifth power supply circuit according to an embodiment of the present application;

[0059] Figure 16 is a structural schematic diagram of a sixth power supply circuit according to an embodiment of the present application;

[0060] Figure 17 is a structural schematic diagram of a seventh power supply circuit according to an embodiment of the present application.

[0061] In the drawings, the meanings of the respective reference numerals are as follows:

[0062] 10, power supply circuit;

[0063] 110, primary winding

[0064] 112, first primary winding

[0065] 114, second primary winding

[0066] 122, first secondary winding

[0067] 124, second secondary winding

[0068] 130, switching circuit

[0069] 142, first rectifying circuit

[0070] 144, second rectifying circuit

[0071] 150, third rectifying circuit

[0072] 20, load circuit DETAILED DESCRIPTION

[0073] In order to make the purpose, technical solutions and advantages of the present application clearer, the embodiments of the present application will be further described in detail below with reference to the drawings.

[0074] It should be understood that the "multiple" mentioned in the present application refers to two or more than two. In the description of the present application, unless otherwise specified, " / " represents the meaning of or, for example, A / B can represent A or B; "and / or" in the present application only describes the relationship between the associated objects, which means that there can be three relationships, for example, A and / or B, which can represent three cases: A exists alone, A and B exist together, and B exists alone. In addition, in order to clearly describe the technical solutions of the present application, the same items or similar items with basically the same function and role are distinguished by using "first", "second" and the like. Those skilled in the art can understand that "first", "second" and the like do not limit the quantity and execution order, and "first", "second" and the like do not necessarily mean different.

[0075] Before the embodiments of the present application are explained in detail, the application scenarios of the embodiments of the present application will be described.

[0076] A transformer generally comprises a primary winding and a secondary winding wound on the same core. The primary winding is also called a primary coil, and the secondary winding is also called a secondary coil. There is electromagnetic induction between the primary winding and the secondary winding. After an input voltage is input into the primary winding, a voltage is also generated in the secondary winding, and the voltage ratio of the primary winding to the secondary winding is equal to the turns ratio of the primary winding to the secondary winding. The primary winding of the transformer can be connected with commercial power to obtain a commercial voltage. The secondary winding of the transformer can be connected with a load circuit such as a power device to supply power to the load circuit. When the commercial voltage input into the primary winding of the transformer is constant, the size of the output voltage of the secondary winding can be adjusted by adjusting the duty cycle of the transformer. The duty cycle refers to the proportion of the time in which the primary winding of the transformer transmits power to the secondary winding in a certain time period.

[0077] The commercial voltage generally comprises 110 V and 220 V. In the related art, when the commercial voltage is switched between 110 V and 220 V, the voltage output from the transformer to the load circuit is generally kept constant by adjusting the duty cycle of the transformer. However, the working efficiency of the transformer is different at different duty cycles, and therefore, adjusting the duty cycle of the transformer affects the working state of the transformer, which is not conducive to efficient power output of the transformer.

[0078] Therefore, an embodiment of the present application provides a power supply circuit and device, which changes the connection mode between a first secondary winding and a second secondary winding of a transformer through a switching circuit, so that the size of the voltage output from the power supply circuit is kept constant on the premise that the duty cycle of the transformer is kept constant.

[0079] The power supply circuit provided by the embodiment of the present application is explained and described in detail below. In each embodiment of the present application, the connection between two electrical devices refers to electrical connection. The electrical connection refers to the connection between two electrical devices through wired or wireless connection for transmission of electrical signals.

[0080] Figure 1 FIG. 1 is a structural schematic diagram of a power supply circuit 10 provided by an embodiment of the present application. Referring to FIG. 1, Figure 1 The power supply circuit 10 comprises a transformer T and a switching circuit 130.

[0081] The transformer T includes a primary winding 110 and a secondary winding. In the embodiment of the present application, the transformer T includes two secondary windings. For the convenience of description, the two secondary windings of the transformer T are referred to as a first secondary winding 122 and a second secondary winding 124. There is electromagnetic induction between the primary winding 110 and the first secondary winding 122 of the transformer T, and there is electromagnetic induction between the primary winding 110 and the second secondary winding 124 of the transformer T. The first secondary winding 122 includes a secondary winding N1 and a secondary winding N2 connected in series. The second secondary winding 124 includes a secondary winding N3 and a secondary winding N4 connected in series. The same terminals of the transformer T are shown in Figure 1 The primary winding 110 can be connected to an alternating current power supply such as a commercial power supply, so that alternating current is passed through the primary winding 110. The first secondary winding 122 and the second secondary winding 124 are both used to supply power to the load circuit 20, and the first secondary winding 122 and the second secondary winding 124 are used to output alternating current.

[0082] In the embodiment of the present application, the primary winding 110 can be connected to an alternating current power supply. The alternating current output from the alternating current power supply to the primary winding 110 includes a first half cycle and a second half cycle in a period. The current flow direction in the first half cycle is opposite to the current flow direction in the second half cycle. According to the same terminals of the transformer T, the secondary winding N1 and the secondary winding N4 output voltages in the same half cycle; the secondary winding N2 and the secondary winding N3 output voltages in the same half cycle.

[0083] The switching circuit 130 is connected between the first secondary winding 122 and the load circuit 20, and is connected between the second secondary winding 124 and the load circuit 20. In other words, the switching circuit 130 is connected between the secondary winding N1 and the load circuit 20, is connected between the secondary winding N2 and the load circuit 20, is connected between the secondary winding N3 and the load circuit 20, and is connected between the secondary winding N4 and the load circuit 20. The switching circuit 130 is used to change the connection mode between the secondary winding N1, the secondary winding N2, the secondary winding N3 and the secondary winding N4. In one case, in the above-mentioned first half cycle, the secondary winding N1 and the secondary winding N4 can be connected in series through the switching circuit 130, and supply power to the load circuit 20; in the above-mentioned second half cycle, the secondary winding N2 and the secondary winding N3 are connected in series through the switching circuit 130, and supply power to the load circuit 20. In another case, in the above-mentioned first half cycle, the secondary winding N1 and the secondary winding N4 can be connected in parallel through the switching circuit 130, and supply power to the load circuit 20; in the above-mentioned second half cycle, the secondary winding N2 and the secondary winding N3 are connected in parallel through the switching circuit 130, and supply power to the load circuit 20.

[0084] For example, if the turns ratio of the secondary winding N1, the secondary winding N2, the secondary winding N3 and the secondary winding N4 is 1:1:1:1. The turns ratio of the primary winding 110 and the secondary winding N1 is M, the turns ratio of the primary winding 110 and the secondary winding N2 is M. The turns ratio of the primary winding 110 and the secondary winding N3 is M, and the turns ratio of the primary winding 110 and the secondary winding N4 is M. When the primary winding 110 is connected to the mains, and the mains voltage is the first voltage (e.g. 110V): in the first half cycle of the first voltage, the secondary winding N1 and the secondary winding N4 are connected in series by the switching circuit 130 and supply power to the load circuit 20, and the input voltage of the load circuit 20 is 110V / M + 110V / M = 220V / M; in the second half cycle of the first voltage, the secondary winding N2 and the secondary winding N3 are connected in series by the switching circuit 130 and supply power to the load circuit 20, and the input voltage of the load circuit 20 is also 110V / M + 110V / M = 220V / M. When the primary winding 110 is connected to the mains, and the mains voltage is the second voltage (e.g. 220V): in the first half cycle of the second voltage, the secondary winding N1 and the secondary winding N4 are connected in parallel by the switching circuit 130 and supply power to the load circuit 20, and the input voltage of the load circuit 20 is 220V / M; in the second half cycle of the second voltage, the secondary winding N2 and the secondary winding N3 are connected in parallel by the switching circuit 130 and supply power to the load circuit 20, and the input voltage of the load circuit 20 is also 220V / M.

[0085] The power supply circuit 10 can change the connection mode between the first secondary winding 122 and the second secondary winding 124 of the transformer T by the switching circuit 130 when the mains voltage changes, so that the voltage output from the power supply circuit 10 to the load circuit 20 remains unchanged. Therefore, the power supply circuit 10 does not need to adjust the duty cycle of the transformer T to keep the voltage output from the power supply circuit 10 to the load circuit 20 unchanged, which improves the turns ratio utilization of the transformer T in the power supply circuit 10, thereby improving the efficiency of the power supply circuit 10 output power.

[0086] It should be understood that in the above description, only the first voltage is 110V and the second voltage is 220V to explain the working process of the power supply circuit 10 of the embodiment of the present application. In other embodiments, the first voltage and the second voltage can also have other values, and the size of the first voltage and the second voltage does not constitute a limitation on the protection scope of the present application.

[0087] Still referring to Figure 1In some embodiments, the first secondary winding 122 includes a first end, a second end and a third end. The secondary winding N1 has a first end and a second end, and the secondary winding N2 also has a first end and a second end. The first end of the secondary winding N1 constitutes the first end of the first secondary winding 122. The second end of the secondary winding N1 and the first end of the secondary winding N2 are connected together, and the second end of the secondary winding N1 and the first end of the secondary winding N2 together constitute the second end of the first secondary winding 122. The second end of the secondary winding N2 constitutes the third end of the first secondary winding 122. In other words, the second end of the first secondary winding 122 is the center tap of the first secondary winding 122. The second secondary winding 124 also includes a first end, a second end and a third end. The secondary winding N3 has a first end and a second end, and the secondary winding N4 also has a first end and a second end. The first end of the secondary winding N3 constitutes the first end of the second secondary winding 124. The second end of the secondary winding N3 and the first end of the secondary winding N4 are connected together, and the second end of the secondary winding N3 and the first end of the secondary winding N4 together constitute the second end of the second secondary winding 124. The second end of the secondary winding N4 constitutes the third end of the second secondary winding 124. In other words, the second end of the second secondary winding 124 is the center tap of the second secondary winding 124.

[0088] The load circuit 20 has an input end and an output end. In the embodiments of the present application, the first end of the first secondary winding 122 is connected to the input end of the load circuit 20, and the third end of the first secondary winding 122 is also connected to the input end of the load circuit 20. The switching circuit 130 is connected between the second end of the first secondary winding 122 and the load circuit 20. The first end of the second secondary winding 124 is connected to the output end of the load circuit 20, and the third end of the second secondary winding 124 is also connected to the output end of the load circuit 20. The switching circuit 130 is connected between the second end of the second secondary winding 124 and the load circuit 20.

[0089] Further, Figure 2 is another structural schematic diagram of the power supply circuit 10 provided by the embodiments of the present application. Please refer to Figure 2 When the electrical signal required by the load circuit 20 is direct current, the input end of the load circuit 20 is positive, and the output end of the load circuit 20 is negative. At this time, the power supply circuit 10 of the present application can further include a first rectifier circuit 142 and a second rectifier circuit 144. The first rectifier circuit 142 and the second rectifier circuit 144 are used to rectify the alternating current output by the first secondary winding 122 and the second secondary winding 124.

[0090] Specifically, the first rectifier circuit 142 has a first end, a second end and a third end. The first end of the first rectifier circuit 142 is connected to the first end of the first secondary winding 122. The second end of the first rectifier circuit 142 is connected to the third end of the first secondary winding 122. The third end of the first rectifier circuit 142 is connected to the input end of the load circuit 20. The second rectifier circuit 144 also has a first end, a second end and a third end. The first end of the second rectifier circuit 144 is connected to the output end of the load circuit 20. The second end of the second rectifier circuit 144 is connected to the first end of the second secondary winding 124. The third end of the second rectifier circuit 144 is connected to the third end of the second secondary winding 124.

[0091] Further, as shown in Figure 2 the first rectifier circuit 142 includes a diode D1 and a diode D2. The second rectifier circuit 144 includes a diode D3 and a diode D4.

[0092] Specifically, the anode of the diode D1 constitutes the first end of the first rectifier circuit 142. That is, the anode of the diode D1 is connected to the first end of the first secondary winding 122, i.e. the anode of the diode D1 is connected to the first end of the secondary winding N1. The anode of the diode D2 constitutes the second end of the first rectifier circuit 142. That is, the anode of the diode D2 is connected to the third end of the first secondary winding 122, i.e. the anode of the diode D2 is connected to the second end of the secondary winding N2. The cathode of the diode D1 and the cathode of the diode D2 are connected together, constituting the third end of the first rectifier circuit 142. That is, both the cathode of the diode D1 and the cathode of the diode D2 are connected to the input end of the load circuit 20.

[0093] The anode of the diode D3 and the anode of the diode D4 are connected together, constituting the first end of the second rectifier circuit 144. That is, both the anode of the diode D3 and the anode of the diode D4 are connected to the output end of the load circuit 20. The cathode of the diode D3 constitutes the second end of the second rectifier circuit 144. That is, the cathode of the diode D3 is connected to the first end of the second secondary winding 124, i.e. the cathode of the diode D3 is connected to the first end of the secondary winding N3. The cathode of the diode D4 constitutes the third end of the second rectifier circuit 144. That is, the cathode of the diode D4 is connected to the third end of the second secondary winding 124, i.e. the cathode of the diode D4 is connected to the second end of the secondary winding N4.

[0094] Still referring to Figure 2In some embodiments, the primary winding 110 of the transformer T can also include a first primary winding 112 and a second primary winding 114. The first primary winding 112 is configured to electromagnetically induce the first secondary winding 122. The second primary winding 114 is configured to electromagnetically induce the second secondary winding 124. The first primary winding 112 and the second primary winding 114 can be connected in series or in parallel to the AC power source. When the primary winding 110 of the transformer T includes the first primary winding 112 and the second primary winding 114 connected in series or in parallel, the primary winding 110 of the transformer T inputs the first voltage, i.e., the first primary winding 112 and the second primary winding 114 both input the first voltage; the primary winding 110 of the transformer T inputs the second voltage, i.e., the first primary winding 112 and the second primary winding 114 both input the second voltage.

[0095] The implementation of the switching circuit 130 in the power supply circuit 10 of the present application will be described below in conjunction with embodiments.

[0096] In the first possible mode, Figure 3 is a structural schematic diagram of the switching circuit 130 provided by the embodiments of the present application, Figure 4 is a structural schematic diagram of the power supply circuit 10 including Figure 3 the switching circuit 130 shown in FIG. 1. Please refer to Figure 3 and Figure 4 The switching circuit 130 has a first end, a second end, a third end, and a fourth end. The first end of the switching circuit 130 is connected to the second end of the first secondary winding 122. The second end of the switching circuit 130 is connected to the second end of the second secondary winding 124. The third end of the switching circuit 130 is connected to the input end of the load circuit 20. The fourth end of the switching circuit 130 is connected to the output end of the load circuit 20.

[0097] Specifically, the switching circuit 130 comprises a switching device K1 and a switching device K2. The switching device K1 comprises a first terminal, a second terminal and a third terminal. The first terminal of the switching device K1 is connected with the second terminal of the first secondary winding 122, and the first terminal of the switching device K1 constitutes the first terminal of the switching circuit 130. The second terminal of the switching device K1 is connected with the output terminal of the load circuit 20, and the second terminal of the switching device K1 constitutes the fourth terminal of the switching circuit 130. The switching device K2 also comprises a first terminal, a second terminal and a third terminal. The first terminal of the switching device K2 is connected with the second terminal of the second secondary winding 124, and the third terminal of the switching device K1 is also connected with the second terminal of the second secondary winding 124. In other words, the first terminal of the switching device K2 and the third terminal of the switching device K1 jointly constitute the second terminal of the switching circuit 130. The second terminal of the switching device K2 is connected with the input terminal of the load circuit 20, and the second terminal of the switching device K2 constitutes the third terminal of the switching circuit 130. The third terminal of the switching device K2 is connected with the second terminal of the first secondary winding 122, i.e. connected to the first terminal of the switching device K1.

[0098] When the primary winding 110 inputs a first voltage (e.g. 110V), as shown in FIG. 2, the first terminal of the switching device K1 and the third terminal of the switching device K1 are connected, and the first terminal of the switching device K2 and the third terminal of the switching device K2 are connected. At this time, the equivalent circuit diagram of the power supply circuit 10 is as shown in FIG. 3. Please refer to FIG. 4, when the power supply circuit 10 works, in the first half cycle of the first voltage, the flow direction of the electric signal is: the electric signal output by the secondary winding N1 is rectified by the diode D1 and input to the load circuit 20. The electric signal output by the load circuit 20 enters the secondary winding N4 after passing through the diode D4. The first terminal of the secondary winding N4 is connected with the second terminal of the secondary winding N1 through the switching circuit 130 (equivalent to a wire in the switching circuit 130). At this time, the secondary winding N1 and the secondary winding N4 are connected in series through the switching circuit 130, and supply power to the load circuit 20. Figure 5 Figure 6 Figure 6 In the second half cycle of the first voltage, the flow direction of the electric signal is: the electric signal output by the secondary winding N2 is rectified by the diode D2 and input to the load circuit 20. The electric signal output by the load circuit 20 enters the secondary winding N3 after passing through the diode D3. The second terminal of the secondary winding N3 is connected with the first terminal of the secondary winding N2 through the switching circuit 130 (equivalent to a wire in the switching circuit 130). At this time, the secondary winding N2 and the secondary winding N3 are connected in series through the switching circuit 130, and supply power to the load circuit 20. Figure 6

[0099] Figure 6

[0100] When the primary winding 110 inputs a second voltage (e.g. 220V), as shown in FIG. 5, the first terminal of the switching device K1 and the third terminal of the switching device K1 are connected, and the first terminal of the switching device K2 and the third terminal of the switching device K2 are connected. At this time, the equivalent circuit diagram of the power supply circuit 10 is as shown in FIG. 6. Please refer to FIG. 7, when the power supply circuit 10 works, in the first half cycle of the second voltage, the flow direction of the electric signal is: the electric signal output by the secondary winding N1 is rectified by the diode D1 and input to the load circuit 20. The electric signal output by the load circuit 20 enters the secondary winding N4 after passing through the diode D4. The first terminal of the secondary winding N4 is connected with the second terminal of the secondary winding N1 through the switching circuit 130 (equivalent to a wire in the switching circuit 130). At this time, the secondary winding N1 and the secondary winding N4 are connected in series through the switching circuit 130, and supply power to the load circuit 20. Figure 7 ​​​​​As shown, the first contact and the second contact of switching device K1 are connected, and the first contact and the second contact of switching device K2 are connected. At this time, the equivalent circuit diagram of power supply circuit 10 is as follows: Figure 8 and Figure 9 As shown. Please see below. Figure 8 When the power supply circuit 10 is working, during the first half-cycle of the second voltage, the direction of the electrical signal flow is as follows: the electrical signal output from the secondary winding N1 is rectified by diode D1 and input to the load circuit 20. The electrical signal output from the load circuit 20 is then processed by the switching circuit 130. Figure 8 The equivalent current (equivalent to a wire) flows back to the secondary winding N1. Simultaneously, the electrical signal output from the secondary winding N4 is switched by circuit 130 (…). Figure 8 The signal (equivalent to a wire) is input to the load circuit 20. The electrical signal output from the load circuit 20 is rectified by diode D4 and flows back to the secondary winding N4. At this time, the secondary windings N1 and N4 are connected in parallel through the switching circuit 130 to supply power to the load circuit 20.

[0101] Please see Figure 9 When the power supply circuit 10 is working, during the second half-cycle of the second voltage, the direction of the electrical signal flow is as follows: the electrical signal output from the secondary winding N2 is rectified by diode D2 and input to the load circuit 20. The electrical signal output from the load circuit 20 is then processed by the switching circuit 130. Figure 8 The electrical signal (equivalent to a wire) flows back to the secondary winding N2. Simultaneously, the electrical signal output from the secondary winding N3 is switched by circuit 130 (…). Figure 8 The signal (equivalent to a wire) is input to the load circuit 20. The electrical signal output from the load circuit 20 is rectified by diode D3 and flows back to the secondary winding N3. At this time, the secondary windings N2 and N3 are connected in parallel through the switching circuit 130 to supply power to the load circuit 20.

[0102] Furthermore, switching devices K1 and K2 can be manually controlled. That is, the user manually controls switching device K1 to connect its second or third contact to its first contact; and manually controls switching device K2 to connect its second or third contact to its first contact. The power supply circuit 10 may also include a controller that detects the magnitude of the input voltage to the primary winding 110. When the controller detects a first voltage input to the primary winding 110, it controls the first and third contacts of switching device K1 and switching device K2 to connect. When the controller detects a second voltage input to the primary winding 110, it controls the first and second contacts of switching device K1 and switching device K2 to connect.

[0103] In the second possible approach, Figure 10is a structural schematic diagram of a switching circuit 130 provided by an embodiment of the present application, Figure 11 is a structural schematic diagram of a power supply circuit 10 of the switching circuit 130. Figure 10 is a structural schematic diagram of a power supply circuit 10 of the switching circuit 130. Please refer to Figure 10 and Figure 11 The switching circuit 130 has a first end, a second end, a third end and a fourth end. The first end of the switching circuit 130 is connected to the second end of the first secondary winding 122. The second end of the switching circuit 130 is connected to the second end of the second secondary winding 124. The third end of the switching circuit 130 is connected to the input end of the load circuit 20. The fourth end of the switching circuit 130 is connected to the output end of the load circuit 20.

[0104] Specifically, the switching circuit 130 includes a transistor VT1, a diode D5, a diode D6 and a diode D7. Among them, the transistor VT1 has a control end, a first end and a second end. The first end of the transistor VT1 is connected to the second end of the first secondary winding 122, and the first end of the transistor VT1 constitutes the first end of the switching circuit 130. The second end of the transistor VT1 is connected to the second end of the second secondary winding 124, and the second end of the transistor VT1 constitutes the second end of the switching circuit 130. The control end of the transistor VT1 is used to control the conduction or disconnection between the first end and the second end of the transistor VT1. The anode of the diode D5 is connected to the second end of the transistor VT1. The cathode of the diode D5 is connected to the input end of the load circuit 20, and the cathode of the diode D5 constitutes the third end of the switching circuit 130. The anode of the diode D6 is connected to the output end of the load circuit 20, and the anode of the diode D6 constitutes the fourth end of the switching circuit 130. The cathode of the diode D6 is connected to the first end of the transistor VT1. The anode of the diode D7 is connected to the first end of the transistor VT1, and the cathode of the diode D7 is connected to the second end of the transistor VT1. Among them, the diode D7 is the parasitic diode of the transistor VT1, which is used to prevent high voltage from breaking through the transistor VT1, thereby achieving the function of freewheeling.

[0105] When the primary winding 110 inputs a first voltage (such as 110V), the control end of the transistor VT1 controls the conduction between the first end and the second end of the transistor VT1. At this time, the equivalent circuit diagram of the power supply circuit 10 is as shown in Figure 12 . Please refer to Figure 12, the power supply circuit 10 works, in the first half cycle of the first voltage, the flow direction of the electrical signal is: the electrical signal output by the secondary winding N1 is rectified by the diode D1 and input to the load circuit 20. The electrical signal output by the load circuit 20 enters the secondary winding N4 after passing through the diode D4. The first end of the secondary winding N4 is connected to the second end of the secondary winding N1 through the transistor VT1 in the switching circuit 130. At this time, the secondary winding N1 and the secondary winding N4 are connected in series through the switching circuit 130, and power is supplied to the load circuit 20. In this process, the anode of the diode D6 is connected to the output end of the load circuit 20, and the voltage at the anode of the diode D6 is equal to the voltage at the second end of the secondary winding N4; the cathode of the diode D6 is connected to the first end of the secondary winding N4 through the transistor VT1, and the voltage at the cathode of the diode D6 is equal to the voltage at the first end of the secondary winding N4, so the diode D6 is cut off. The anode of the diode D5 is connected to the first end of the secondary winding N4, and the voltage at the anode of the diode D5 is equal to the voltage at the first end of the secondary winding N4; the cathode of the diode D5 is connected to the input end of the load circuit 20, and the voltage at the cathode of the diode D5 is equal to the voltage at the first end of the secondary winding N1, so the diode D5 is cut off.

[0106] In the second half cycle of the first voltage, the flow direction of the electrical signal is: the electrical signal output by the secondary winding N2 is rectified by the diode D2 and input to the load circuit 20. The electrical signal output by the load circuit 20 enters the secondary winding N3 after passing through the diode D3. The second end of the secondary winding N3 is connected to the first end of the secondary winding N2 through the transistor VT1 in the switching circuit 130. At this time, the secondary winding N2 and the secondary winding N3 are connected in series through the switching circuit 130, and power is supplied to the load circuit 20. In this process, the anode of the diode D6 is connected to the output end of the load circuit 20, and the voltage at the anode of the diode D6 is equal to the voltage at the first end of the secondary winding N3; the cathode of the diode D6 is connected to the second end of the secondary winding N3 through the transistor VT1, and the voltage at the cathode of the diode D6 is equal to the voltage at the second end of the secondary winding N3, so the diode D6 is cut off. The anode of the diode D5 is connected to the second end of the secondary winding N3, and the voltage at the anode of the diode D5 is equal to the voltage at the second end of the secondary winding N3; the cathode of the diode D5 is connected to the input end of the load circuit, and the voltage at the cathode of the diode D5 is equal to the voltage at the second end of the secondary winding N2, so the diode D5 is cut off.

[0107] When the primary winding 110 inputs the second voltage (such as 220V), the control end of the transistor VT1 controls the first end and the second end of the transistor VT1 to be disconnected. At this time, the equivalent circuit diagram of the power supply circuit 10 is as shown in Figure 13 and Figure 14 Please refer to Figure 13The power supply circuit 10 works as follows. In the first half cycle of the second voltage, the flow direction of the electric signal is as follows: the electric signal output by the secondary winding N1 is rectified by the diode D1 and input to the load circuit 20. The electric signal output by the load circuit 20 flows back to the secondary winding N1 through the diode D6 in the switching circuit 130. Meanwhile, the electric signal output by the secondary winding N4 is input to the load circuit 20 through the diode D5 in the switching circuit 130. The electric signal output by the load circuit 20 flows back to the secondary winding N4 through the diode D4. At this time, the secondary winding N1 and the secondary winding N4 are connected in parallel through the switching circuit 130 to supply power to the load circuit 20.

[0108] Please refer to Figure 14 The power supply circuit 10 works as follows. In the first half cycle of the second voltage, the flow direction of the electric signal is as follows: the electric signal output by the secondary winding N1 is rectified by the diode D1 and input to the load circuit 20. The electric signal output by the load circuit 20 flows back to the secondary winding N1 through the diode D6 in the switching circuit 130. Meanwhile, the electric signal output by the secondary winding N4 is input to the load circuit 20 through the diode D5 in the switching circuit 130. The electric signal output by the load circuit 20 flows back to the secondary winding N4 through the diode D4. At this time, the secondary winding N1 and the secondary winding N4 are connected in parallel through the switching circuit 130 to supply power to the load circuit 20.

[0109] Further, the transistor VT1 can be manually controlled. That is, a user manually inputs a first level signal to the control end of the transistor VT1 to make the first end and the second end of the transistor VT1 conductive; or the user manually inputs a second level signal to the control end of the transistor VT1 to make the first end and the second end of the transistor VT1 non-conductive. The power supply circuit 10 can also include a controller. The controller detects the size of the input voltage of the primary winding 110. When the controller detects that the primary winding 110 inputs a first voltage, the controller inputs a first level signal to the control end of the transistor VT1 to make the first end and the second end of the transistor VT1 conductive. When the controller detects that the primary winding 110 inputs a second voltage, the controller inputs a second level signal to the control end of the transistor VT1 to make the first end and the second end of the transistor VT1 non-conductive. The first level signal is one of a low level signal and a high level signal, and the second level signal is the other of the low level signal and the high level signal. The high and low of the first level signal and the second level signal depend on the type of the transistor VT1.

[0110] When the primary winding 110 inputs the first voltage, in the first half cycle of the first voltage, the secondary winding N1 and the secondary winding N4 supply power to the load circuit 20 in series through the switching circuit 130; in the second half cycle of the first voltage, the secondary winding N2 and the secondary winding N3 supply power to the load circuit 20 in series through the switching circuit 130. At this time, the diode D1, the diode D2, the diode D3 and the diode D4 form a full-bridge rectifier circuit. When the primary winding 110 inputs the second voltage, in the first half cycle of the second voltage, the secondary winding N1 and the secondary winding N4 supply power to the load circuit 20 in parallel through the switching circuit 130; in the second half cycle of the second voltage, the secondary winding N2 and the secondary winding N3 supply power to the load circuit 20 in parallel through the switching circuit 130. At this time, the diode D1, the diode D2, the diode D3 and the diode D4 form a full-wave rectifier circuit. The power supply circuit 10, whether it is input the first voltage or the second voltage, the first secondary winding 122, the second secondary winding 124, the diode D1, the diode D2, the diode D3 and the diode D4 are always in working condition, which improves the utilization rate of the devices in the power supply circuit 10, thereby improving the working life of the power supply circuit 10. In the power supply circuit 10, the diode D1, the diode D2, the diode D3 and the diode D4 can use diodes with the same voltage resistance value, thereby reducing the material cost of the power supply circuit 10 and reducing the power loss.

[0111] Further, in the embodiments of the present application, the transistor VT1 can be a BJT (Bipolar Junction Transistor) or a MOS (Metal Oxide Semiconductor) tube. The bipolar transistor can also be an IGBT (Insulated Gate Bipolar Transistor).

[0112] Figure 15 is another structure schematic diagram of the power supply circuit 10 provided by the embodiments of the present application. Please refer to Figure 15 In some embodiments, the power supply circuit 10 of the present application further comprises a third rectifier circuit 150.

[0113] Specifically, the third rectifying circuit 150 has a first end, a second end and a third end. The first end of the third rectifying circuit 150 is connected with the first end of the first secondary winding 122, and the first end of the third rectifying circuit 150 is connected with the third end of the first secondary winding 122. The second end of the third rectifying circuit 150 is connected with the input end of the load circuit 20. The third end of the third rectifying circuit 150 is connected with the output end of the load circuit 20, and the third end of the third rectifying circuit 150 is connected with the first end of the second secondary winding 124 and the third end of the second secondary winding 124. In the power supply circuit 10, the third rectifying circuit 150 can further rectify the electrical signal input to the load circuit 20, so as to make the electrical signal input by the load circuit 20 more stable.

[0114] Further, Figure 16 and Figure 17 The circuit structure diagram of the third rectifying circuit 150 is shown. Please refer to Figure 16 and Figure 17 The third rectifying circuit 150 includes an inductor L1 and a capacitor C1. The first end of the inductor L1 is connected with the first end of the first secondary winding 122, and the first end of the inductor L1 is connected with the third end of the first secondary winding 122. The second end of the inductor L1 is connected with the input end of the load circuit 20. The first pole plate of the capacitor C1 is connected with the second end of the inductor L1. The second pole plate of the capacitor C1 is connected with the output end of the load circuit 20. The second pole plate of the capacitor C1 is connected with the first end of the second secondary winding 124 and the third end of the second secondary winding 124.

[0115] Please refer to Figure 16 When the switching circuit 130 includes the switching device K1 and the switching device K2, it is known from the above description that the second contact of the switching device K2 constitutes the third end of the switching circuit 130. In the present embodiment, the third end of the switching circuit 130 is connected with the input end of the load circuit 20 through the third rectifying circuit 150. In other words, the second contact of the switching device K2 is connected with the first end of the inductor L1. The second contact of the switching device K1 constitutes the fourth end of the switching circuit 130. In the present embodiment, the second contact of the switching device K1 is connected with the output end of the load circuit 20, and the second contact of the switching device K1 is connected with the second pole plate of the capacitor C1.

[0116] Please refer to Figure 17When the switching circuit 130 includes the transistor VTl, the diode D5, the diode D6, and the diode D7, as is known from the above description, the cathode of the diode D5 constitutes the third terminal of the switching circuit 130. In the present embodiment, the third terminal of the switching circuit 130 is connected to the input terminal of the load circuit 20 through the third rectifying circuit 150. In other words, the cathode of the diode D5 is connected to the first terminal of the inductor LI. The anode of the diode D6 constitutes the fourth terminal of the switching circuit 130. In the present embodiment, the anode of the diode D6 is connected to the output terminal of the load circuit 20, and the anode of the diode D6 is connected to the second plate of the capacitor CI.

[0117] In the embodiment of the present application, the power supply circuit 10 comprises a transformer T and a switching circuit 130. The transformer T comprises a primary winding 110, a first secondary winding 122 and a second secondary winding 124. The first secondary winding 122 comprises a secondary winding N1 and a secondary winding N2 connected in series. The second secondary winding 124 comprises a secondary winding N3 and a secondary winding N4 connected in series. The switching circuit 130 is connected between the first secondary winding 122 and the load circuit 20, and is connected between the second secondary winding 124 and the load circuit 20. The primary winding 110 can be connected with the mains. When the power supply circuit 10 is working, if the mains voltage is a first voltage of 110V, in a first half cycle of the first voltage, the secondary winding N1 and the secondary winding N4 are connected in series through the switching circuit 130 to supply power to the load circuit 20; in a second half cycle of the first voltage, the secondary winding N2 and the secondary winding N3 are connected in series through the switching circuit 130 to supply power to the load circuit 20. If the mains voltage is a second voltage of 220V, in a first half cycle of the second voltage, the secondary winding N1 and the secondary winding N4 are connected in parallel through the switching circuit 130 to supply power to the load circuit 20; in a second half cycle of the second voltage, the secondary winding N2 and the secondary winding N3 are connected in parallel through the switching circuit 130 to supply power to the load circuit 20. When the mains voltage changes, the power supply circuit 10 can change the connection mode between the first secondary winding 122 and the second secondary winding 124 of the transformer T through the switching circuit 130, so that the voltage output from the power supply circuit 10 to the load circuit 20 remains unchanged. Therefore, the power supply circuit 10 does not need to adjust the duty cycle of the transformer T to keep the voltage output from the power supply circuit 10 to the load circuit 20 unchanged, improves the utilization rate of the turns ratio of the transformer in the power supply circuit 10, and thus can improve the efficiency of the power supply circuit 10 in outputting electric energy. In the power supply circuit 10, whether the primary winding 110 inputs the first voltage or the second voltage, the first secondary winding 122, the second secondary winding 124, the diode D1, the diode D2, the diode D3 and the diode D4 are always in working state, which improves the utilization rate of the devices in the power supply circuit 10, and thus can improve the working life of the power supply circuit 10. In the power supply circuit 10, the diode D1, the diode D2, the diode D3 and the diode D4 can use diodes with the same withstand voltage, so as to reduce the material cost of the power supply circuit 10 and reduce the electric energy loss.

[0118] The embodiment of the present application also provides a power supply device, which comprises the power supply circuit 10 in any one of the above embodiments.

[0119] Specifically, the power supply circuit 10 comprises a transformer T and a switching circuit 130. The transformer T comprises a primary winding 110, a first secondary winding 122 and a second secondary winding 124. The first secondary winding 122 comprises a secondary winding N1 and a secondary winding N2 connected in series. The second secondary winding 124 comprises a secondary winding N3 and a secondary winding N4 connected in series. The switching circuit 130 is connected between the first secondary winding 122 and the load circuit 20, and the switching circuit 130 is connected between the second secondary winding 124 and the load circuit 20. When the primary winding 110 inputs a first voltage, the secondary winding N1 and the secondary winding N4 are connected in series through the switching circuit 130, and the secondary winding N2 and the secondary winding N3 are connected in series through the switching circuit 130 to supply power to the load circuit 20. When the primary winding 110 inputs a second voltage, the secondary winding N1 and the secondary winding N4 are connected in parallel through the switching circuit 130, and the secondary winding N2 and the secondary winding N3 are connected in parallel through the switching circuit 130 to supply power to the load circuit 20.

[0120] In some embodiments, the first secondary winding 122 comprises a first end, a second end and a third end. The first end of the first secondary winding 122 is the first end of the secondary winding N1. The second end of the secondary winding N1 is connected with the first end of the secondary winding N2, and the second end of the secondary winding N1 and the first end of the secondary winding N2 constitute the second end of the first secondary winding 122. The second end of the secondary winding N2 is the third end of the first secondary winding 122. The switching circuit 130 is connected between the second end of the first secondary winding 122 and the load circuit 20. The first end and the third end of the first secondary winding 122 are both connected with the input end of the load circuit 20.

[0121] The second secondary winding 124 comprises a first end, a second end and a third end. The first end of the second secondary winding 124 is the first end of the secondary winding N3. The second end of the secondary winding N3 is connected with the first end of the secondary winding N4, and the second end of the secondary winding N3 and the first end of the secondary winding N4 constitute the second end of the second secondary winding 124. The second end of the secondary winding N4 is the third end of the second secondary winding 124. The switching circuit 130 is connected between the second end of the second secondary winding 124 and the load circuit 20. The first end and the third end of the second secondary winding 124 are both connected with the output end of the load circuit 20.

[0122] In some embodiments, the power supply circuit 10 further comprises a first rectifier circuit 142 and a second rectifier circuit 144.

[0123] The first end of the first rectifier circuit 142 is connected with the first end of the first secondary winding 122, and the second end of the first rectifier circuit 142 is connected with the third end of the first secondary winding 122. The third end of the first rectifier circuit 142 is connected with the input end of the load circuit 20.

[0124] A first end of the second rectifying circuit 144 is connected to an output end of the load circuit 20. A second end of the second rectifying circuit 144 is connected to a first end of the second secondary winding 124, and a third end of the second rectifying circuit 144 is connected to a third end of the second secondary winding 124.

[0125] In some embodiments, the first rectifying circuit 142 includes a diode D1 and a diode D2. The second rectifying circuit 144 includes a diode D3 and a diode D4.

[0126] An anode of the diode D1 is connected to a first end of the first secondary winding 122, and a cathode of the diode D1 is connected to an input end of the load circuit 20.

[0127] An anode of the diode D2 is connected to a third end of the first secondary winding 122, and a cathode of the diode D1 is connected to the input end of the load circuit 20.

[0128] An anode of the diode D3 is connected to an output end of the load circuit 20, and a cathode of the diode D3 is connected to the first end of the second secondary winding 124.

[0129] An anode of the diode D4 is connected to the output end of the load circuit 20, and a cathode of the diode D4 is connected to the third end of the second secondary winding 124.

[0130] In some embodiments, the switching circuit 130 has a first end, a second end, a third end, and a fourth end.

[0131] The first end of the switching circuit 130 is connected to the second end of the first secondary winding 122, the second end of the switching circuit 130 is connected to the second end of the second secondary winding 124, the third end of the switching circuit 130 is connected to the input end of the load circuit 20, and the fourth end of the switching circuit 130 is connected to the output end of the load circuit 20.

[0132] In other embodiments, the switching circuit 130 includes a switching device K1 and a switching device K2.

[0133] The switching device K1 includes a first contact, a second contact, and a third contact. The first contact of the switching device K1 is connected to the second end of the first secondary winding 122, the second contact of the switching device K1 is connected to the output end of the load circuit 20, and the third contact of the switching device K1 is connected to the second end of the second secondary winding 124.

[0134] The switching device K2 includes a first contact, a second contact, and a third contact. The first contact of the switching device K2 is connected to the second end of the second secondary winding 124, the second contact of the switching device K2 is connected to the input end of the load circuit 20, and the third contact of the switching device K2 is connected to the second end of the first secondary winding 122.

[0135] When the first terminal of the switching device K1 and the second terminal of the switching device K1 are connected, and the first terminal of the switching device K2 and the second terminal of the switching device K2 are connected, the secondary winding N1 and the secondary winding N4 are connected in parallel, and the secondary winding N2 and the secondary winding N3 are connected in parallel. When the first terminal of the switching device K1 and the third terminal of the switching device K1 are connected, and the first terminal of the switching device K2 and the third terminal of the switching device K2 are connected, the secondary winding N1 and the secondary winding N4 are connected in series, and the secondary winding N2 and the secondary winding N3 are connected in series.

[0136] In some embodiments, the switching circuit 130 comprises a transistor VT1, a diode D5, a diode D6, and a diode D7.

[0137] The transistor VT1 has a control terminal, a first terminal, and a second terminal. The first terminal of the transistor VT1 is connected to the second terminal of the first secondary winding 122. The second terminal of the transistor VT1 is connected to the second terminal of the second secondary winding 124.

[0138] The anode of the diode D5 is connected to the second terminal of the transistor VT1. The cathode of the diode D5 is connected to the input terminal of the load circuit 20.

[0139] The anode of the diode D6 is connected to the output terminal of the load circuit 20. The cathode of the diode D6 is connected to the first terminal of the transistor VT1.

[0140] The anode of the diode D7 is connected to the first terminal of the transistor VT1. The cathode of the diode D7 is connected to the second terminal of the transistor VT1.

[0141] When the first terminal of the transistor VT1 and the second terminal of the transistor VT1 are connected, the secondary winding N1 and the secondary winding N4 are connected in series, and the secondary winding N2 and the secondary winding N3 are connected in series. When the first terminal of the transistor VT1 and the second terminal of the transistor VT1 are disconnected, the secondary winding N1 and the secondary winding N4 are connected in parallel, and the secondary winding N2 and the secondary winding N3 are connected in parallel.

[0142] In some embodiments, the power supply circuit 10 further comprises a third rectifying circuit 150.

[0143] The third rectifying circuit 150 has a first terminal, a second terminal, and a third terminal. The first terminal of the third rectifying circuit 150 is connected to the first terminal of the first secondary winding 122, and the first terminal of the third rectifying circuit 150 is connected to the third terminal of the first secondary winding 122. The second terminal of the third rectifying circuit 150 is connected to the input terminal of the load circuit 20. The third terminal of the third rectifying circuit 150 is connected to the output terminal of the load circuit 20, and the third terminal of the third rectifying circuit 150 is connected to the first terminal of the second secondary winding 124 and the third terminal of the second secondary winding 124.

[0144] In some embodiments, the third rectifying circuit 150 comprises an inductor L1 and a capacitor C1.

[0145] The first end of the inductor L1 is connected to the first end of the first secondary winding 122, and the first end of the inductor L1 is connected to the third end of the first secondary winding 122. The second end of the inductor L1 is connected to the input end of the load circuit 20.

[0146] The first plate of the capacitor C1 is connected to the second end of the inductor L1, the second plate of the capacitor C1 is connected to the output end of the load circuit 20, and the second plate of the capacitor C1 is connected to the first end of the second secondary winding 124 and the third end of the second secondary winding 124.

[0147] In the embodiments of the present application, the power supply circuit 10 comprises a transformer T and a switching circuit 130. The transformer T comprises a primary winding 110, a first secondary winding 122 and a second secondary winding 124. The first secondary winding 122 comprises a secondary winding N1 and a secondary winding N2 connected in series. The second secondary winding 124 comprises a secondary winding N3 and a secondary winding N4 connected in series. The switching circuit 130 is connected between the first secondary winding 122 and the load circuit 20, and is connected between the second secondary winding 124 and the load circuit 20. The primary winding 110 can be connected to the mains. When the power supply circuit 10 is working, if the mains voltage is a first voltage of 110V, then in the first half cycle of the first voltage, the secondary winding N1 and the secondary winding N4 are connected in series through the switching circuit 130 to supply power to the load circuit 20; in the second half cycle of the first voltage, the secondary winding N2 and the secondary winding N3 are connected in series through the switching circuit 130 to supply power to the load circuit 20. If the mains voltage is a second voltage of 220V, then in the first half cycle of the second voltage, the secondary winding N1 and the secondary winding N4 are connected in parallel through the switching circuit 130 to supply power to the load circuit 20; in the second half cycle of the second voltage, the secondary winding N2 and the secondary winding N3 are connected in parallel through the switching circuit 130 to supply power to the load circuit 20. When the mains voltage changes, the power supply circuit 10 can change the connection mode between the first secondary winding 122 and the second secondary winding 124 of the transformer T through the switching circuit 130, so that the voltage output from the power supply circuit 10 to the load circuit 20 remains unchanged. Therefore, the power supply circuit 10 does not need to adjust the duty cycle of the transformer T to keep the voltage output from the power supply circuit 10 to the load circuit 20 unchanged, which improves the utilization rate of the turns ratio of the transformer T in the power supply circuit 10, thereby improving the efficiency of the power supply circuit 10 in outputting electric energy.

[0148] The above-described embodiments are only used to illustrate the technical solutions of the present application, but not limit them; although the present application is described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement to part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should be included in the protection scope of the present application.

Claims

1. A power supply circuit, characterized in that, Includes: a transformer T and a switching circuit, wherein the transformer T includes a primary winding, a first secondary winding and a second secondary winding; The first secondary winding includes secondary winding N1 and secondary winding N2 connected in series, and the second secondary winding includes secondary winding N3 and secondary winding N4 connected in series. The switching circuit is connected between the first secondary winding and the load circuit, and the switching circuit is also connected between the second secondary winding and the load circuit. When the primary winding is input with a first voltage, the secondary windings N1 and N4 are connected in series through the switching circuit, and the secondary windings N2 and N3 are connected in series through the switching circuit to supply power to the load circuit. When the primary winding is input with a second voltage, the secondary windings N1 and N4 are connected in parallel through the switching circuit, and the secondary windings N2 and N3 are connected in parallel through the switching circuit to supply power to the load circuit. The second voltage is twice the first voltage. The first secondary winding includes a first end, a second end, and a third end. The first end of the secondary winding N1 is the first end of the first secondary winding. The second end of the secondary winding N1 is connected to the first end of the secondary winding N2, and the second end of the secondary winding N1 and the first end of the secondary winding N2 constitute the second end of the first secondary winding. The second end of the secondary winding N2 is the third end of the first secondary winding. The switching circuit is connected between the second end of the first secondary winding and the load circuit. Both the first end and the third end of the first secondary winding are connected to the input end of the load circuit. The second secondary winding includes a first end, a second end, and a third end. The first end of the secondary winding N3 is the first end of the second secondary winding. The second end of the secondary winding N3 is connected to the first end of the secondary winding N4, and the second end of the secondary winding N3 and the first end of the secondary winding N4 constitute the second end of the second secondary winding. The second end of the secondary winding N4 is the third end of the second secondary winding. The switching circuit is connected between the second end of the second secondary winding and the load circuit. Both the first end and the third end of the second secondary winding are connected to the output terminal of the load circuit. The switching circuit has a first terminal, a second terminal, a third terminal, and a fourth terminal; the first terminal of the switching circuit is connected to the second terminal of the first secondary winding, the second terminal of the switching circuit is connected to the second terminal of the second secondary winding, the third terminal of the switching circuit is connected to the input terminal of the load circuit, and the fourth terminal of the switching circuit is connected to the output terminal of the load circuit.

2. The power supply circuit as described in claim 1, characterized in that, Also includes: First rectifier circuit and second rectifier circuit; The first terminal of the first rectifier circuit is connected to the first terminal of the first secondary winding, and the second terminal of the first rectifier circuit is connected to the third terminal of the first secondary winding; the third terminal of the first rectifier circuit is connected to the input terminal of the load circuit. The first terminal of the second rectifier circuit is connected to the output terminal of the load circuit; the second terminal of the second rectifier circuit is connected to the first terminal of the second secondary winding, and the third terminal of the second rectifier circuit is connected to the third terminal of the second secondary winding.

3. The power supply circuit as described in claim 2, characterized in that, The first rectifier circuit includes diode D1 and diode D2; the second rectifier circuit includes diode D3 and diode D4. The anode of diode D1 is connected to the first end of the first secondary winding, and the cathode of diode D1 is connected to the input terminal of the load circuit. The anode of diode D2 is connected to the third terminal of the first secondary winding, and the cathode of diode D2 is connected to the input terminal of the load circuit. The anode of diode D3 is connected to the output terminal of the load circuit, and the cathode of diode D3 is connected to the first terminal of the second secondary winding. The anode of diode D4 is connected to the output terminal of the load circuit, and the cathode of diode D4 is connected to the third terminal of the second secondary winding.

4. The power supply circuit as described in claim 1, characterized in that, The switching circuit includes: switching device K1 and switching device K2; The switching device K1 includes a first contact, a second contact, and a third contact. The first contact of the switching device K1 is connected to the second end of the first secondary winding, the second contact of the switching device K1 is connected to the output end of the load circuit, and the third contact of the switching device K1 is connected to the second end of the second secondary winding. The switching device K2 includes a first contact, a second contact, and a third contact. The first contact of the switching device K2 is connected to the second end of the second secondary winding, the second contact of the switching device K2 is connected to the input end of the load circuit, and the third contact of the switching device K2 is connected to the second end of the first secondary winding. When the first contact of the switching device K1 is connected to the second contact of the switching device K1, and the first contact of the switching device K2 is connected to the second contact of the switching device K2, the secondary winding N1 and the secondary winding N4 are connected in parallel, and the secondary winding N2 and the secondary winding N3 are connected in parallel; when the first contact of the switching device K1 is connected to the third contact of the switching device K1, and the first contact of the switching device K2 is connected to the third contact of the switching device K2, the secondary winding N1 and the secondary winding N4 are connected in series, and the secondary winding N2 and the secondary winding N3 are connected in series.

5. The power supply circuit as described in claim 1, characterized in that, The switching circuit includes: transistor VT1, diode D5, diode D6, and diode D7; The transistor VT1 has a control terminal, a first terminal, and a second terminal. The first terminal of the transistor VT1 is connected to the second terminal of the first secondary winding, and the second terminal of the transistor VT1 is connected to the second terminal of the second secondary winding. The anode of diode D5 is connected to the second terminal of transistor VT1, and the cathode of diode D5 is connected to the input terminal of the load circuit. The anode of diode D6 is connected to the output terminal of the load circuit, and the cathode of diode D6 is connected to the first terminal of transistor VT1. The anode of diode D7 is connected to the first terminal of transistor VT1, and the cathode of diode D7 is connected to the second terminal of transistor VT1. When the first terminal of transistor VT1 is connected to the second terminal of transistor VT1, the secondary winding N1 and the secondary winding N4 are connected in series, and the secondary winding N2 and the secondary winding N3 are connected in series; when the first terminal of transistor VT1 is disconnected from the second terminal of transistor VT1, the secondary winding N1 and the secondary winding N4 are connected in parallel, and the secondary winding N2 and the secondary winding N3 are connected in parallel.

6. The power supply circuit as described in claim 1, characterized in that, Also includes: Third rectifier circuit; The third rectifier circuit has a first terminal, a second terminal, and a third terminal; the first terminal of the third rectifier circuit is connected to the first terminal of the first secondary winding, and the first terminal of the third rectifier circuit is connected to the third terminal of the first secondary winding; the second terminal of the third rectifier circuit is connected to the input terminal of the load circuit; the third terminal of the third rectifier circuit is connected to the output terminal of the load circuit, and the third terminal of the third rectifier circuit is connected to the first terminal of the second secondary winding and the third terminal of the second secondary winding.

7. The power supply circuit as described in claim 6, characterized in that, The third rectifier circuit includes: inductor L1 and capacitor C1; The first end of the inductor L1 is connected to the first end of the first secondary winding, and the first end of the inductor L1 is connected to the third end of the first secondary winding; the second end of the inductor L1 is connected to the input end of the load circuit. The first plate of capacitor C1 is connected to the second end of inductor L1, the second plate of capacitor C1 is connected to the output end of the load circuit, and the second plate of capacitor C1 is connected to the first end of the second secondary winding and the third end of the second secondary winding.

8. A power supply device, characterized in that, Includes the power supply circuit as described in any one of claims 1 to 7.

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