CN115104253A

CN115104253A - Power supply circuit and power supply device

Info

Publication number: CN115104253A
Application number: CN202180000049.5A
Authority: CN
Inventors: 戴烜赫; 王译娴
Original assignee: Shenzhen Jasic Technology Co ltd
Current assignee: Shenzhen Jasic Technology Co ltd
Priority date: 2021-01-22
Filing date: 2021-01-22
Publication date: 2022-09-23
Also published as: DE212021000183U1; WO2022155898A1

Abstract

The application discloses power supply circuit and device belongs to the technical field of circuits. The power supply circuit includes 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 includes a secondary winding N3 and a secondary winding N4 in series. When the voltage of the mains supply changes, the power 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 to the load circuit by the power circuit is kept unchanged. Therefore, the power circuit can keep the voltage output to the load circuit by the power circuit unchanged without adjusting the duty ratio of the transformer T, thereby improving the efficiency of the power circuit for outputting electric energy.

Description

Power supply circuit and power supply device

Technical Field

The present disclosure relates to circuit technologies, and particularly to a power supply circuit and a power supply device.

Background

With the rapid development of scientific technology, the relationship between power equipment and human life is becoming more and more intimate. The mains supply supplies power to the electrical equipment through a transformer, and the voltage of the mains supply generally comprises both 110 volts and 220 volts.

In the related art, when the commercial power voltage is switched between 110v and 220v, the duty ratio of the transformer is usually adjusted to keep the voltage output by the transformer constant.

However, adjusting the duty ratio of the transformer affects the working state of the transformer, which is not favorable for the transformer to output electric energy efficiently.

Technical problem

The embodiment of the application provides a power supply circuit and a power supply device, the connection mode between a first secondary winding and a second secondary winding of a transformer T is changed through a switching circuit, and the voltage output by the power supply circuit can be kept unchanged on the premise of keeping the duty ratio of the transformer T unchanged.

Technical solution

In a first aspect, a power supply circuit is provided, including: 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 which are connected in series, and the second secondary winding comprises a secondary winding N3 and a secondary winding N4 which are connected in series;

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;

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;

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.

Optionally, 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 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, and 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; the first end and the third end of the first secondary winding are both connected with the input end of the load circuit;

the second secondary winding comprises 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 with the first end of the secondary winding N4, the second end of the secondary winding N3 and the first end of the secondary winding N4 form the second end of the second secondary winding, and 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; and the first end and the third end of the second secondary winding are both connected with the output end of the load circuit.

Optionally, the power supply circuit further comprises: a first rectifying circuit and a second rectifying circuit;

the first end of the first rectifying circuit is connected with the first end of the first secondary winding, and the second end of the first rectifying circuit is connected with the third end of the first secondary winding; the third end of the first rectifying circuit is connected with the input end of the load circuit;

the first end of the second rectifying circuit is connected with the output end of the load circuit; and the second end of the second rectifying circuit is connected with the first end of the second secondary winding, and the third end of the second rectifying circuit is connected with the third end of the second secondary winding.

Optionally, the first rectification circuit comprises: diode D1 and diode D2; the second rectification circuit includes: diode D3 and diode D4;

the anode of the diode D1 is connected with the first end of the first secondary winding, and the cathode of the diode D1 is connected with the input end of the load circuit;

the anode of the diode D2 is connected with the third end of the first secondary winding, and the cathode of the diode D1 is connected with the input end of the load circuit;

the anode of the diode D3 is connected with the output end of the load circuit, and the cathode of the diode D3 is connected with the first end of the second secondary winding;

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

Optionally, the switching circuit has a first terminal, a second terminal, a third terminal and a fourth terminal;

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.

Optionally, the switching circuit comprises: switching device K1 and switching device K2;

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;

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;

when the first contact of the switching device K1 is connected with the second contact of the switching device K1, and the first contact of the switching device K2 is connected with the second contact of the switching device K2, the secondary winding N1 is connected in parallel with the secondary winding N4, and the secondary winding N2 is connected in parallel with the secondary winding N3; when the first contact of the switching device K1 is connected with the third contact of the switching device K1, and the first contact of the switching device K2 is connected with the third contact of the switching device K2, the secondary winding N1 is connected with the secondary winding N4 in series, and the secondary winding N2 is connected with the secondary winding N3 in series.

Optionally, the switching circuit comprises: a transistor VT1, a diode D5, a diode D6, and a 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 with the second terminal of the first secondary winding, the second terminal of the transistor VT1 is connected with the second terminal of the second secondary winding;

the anode of the diode D5 is connected to the second terminal of the transistor VT1, and the cathode of the diode D5 is connected to the input terminal of the load circuit;

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 VT 1;

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 VT 1;

when the first end of the transistor VT1 is conducted with the second end of the transistor VT1, the secondary winding N1 is connected in series with the secondary winding N4, and the secondary winding N2 is connected in series with the secondary winding N3; when the first end of the transistor VT1 is disconnected from the second end of the transistor VT1, the secondary winding N1 is connected in parallel with the secondary winding N4, and the secondary winding N2 is connected in parallel with the secondary winding N3.

Optionally, the power supply circuit further comprises: a third rectifying circuit;

the third rectifying circuit is provided with a first end, a second end and a third end; the first end of the third rectifying circuit is connected with the first end of the first secondary winding, and the first end of the third rectifying circuit is connected with the third end of the first secondary winding; the second end of the third rectifying circuit is connected with the input end of the load circuit; and the third end of the third rectifying circuit is connected with the output end of the load circuit, and the third end of the third rectifying circuit is connected with the first end of the second secondary winding and the third end of the second secondary winding.

Optionally, the third rectification circuit comprises: 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, and the first end of the inductor L1 is connected with the third end of the first secondary winding; a second terminal of the inductor L1 is connected to an input terminal of the load circuit;

the first polar plate of electric capacity C1 with the second end of inductance L1 is connected, the second polar plate of electric capacity C1 with load circuit's output is connected, just the second polar plate of electric capacity C1 with the first end of second secondary winding with the third end of second secondary winding is connected.

In a second aspect, a power supply apparatus is provided, comprising the power supply circuit as described in the first aspect.

Advantageous effects

In the present application, the power supply circuit includes 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 which are connected in series, and the second secondary winding comprises a secondary winding N3 and a secondary winding N4 which are connected in series. The switching circuit is connected between the first secondary winding and the load circuit, and between the second secondary winding and the load circuit. The primary winding may be connected to mains. When the power supply circuit works, if 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 period of the first voltage; during the second half cycle of the first voltage, the secondary winding N2 and the secondary winding N3 supply power to the load circuit in series through the switching circuit. If the mains voltage is a second voltage of 220V, the secondary winding N1 and the secondary winding N4 supply power to the load circuit in parallel through the switching circuit in the first half period of the second voltage; during a second half cycle of the second voltage, the secondary winding N2 and the secondary winding N3 supply power in parallel through the switching circuit to the load circuit. 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 is kept unchanged. Therefore, the power supply circuit can keep the voltage output to the load circuit unchanged without adjusting the duty ratio of the transformer T, thereby improving the efficiency of the power supply circuit for outputting electric energy.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

Fig. 1 is a schematic structural diagram of a first power supply circuit provided in an embodiment of the present application;

fig. 2 is a schematic structural diagram of a second power supply circuit provided in an embodiment of the present application;

fig. 3 is a schematic structural diagram of a first switching circuit according to an embodiment of the present disclosure;

fig. 4 is a schematic structural diagram of a third power supply circuit provided in the embodiment of the present application;

fig. 5 is a schematic structural diagram of a power circuit according to an embodiment of the present application when a first voltage is input;

fig. 6 is an equivalent circuit diagram of a first power circuit provided in an embodiment of the present application when a first voltage is input;

fig. 7 is a schematic structural diagram of a power circuit according to an embodiment of the present disclosure when a second voltage is input;

fig. 8 is an equivalent circuit diagram of a first power circuit provided in an embodiment of the present application when a second voltage is input;

fig. 9 is an equivalent circuit diagram of a second power circuit provided in an embodiment of the present application when a second voltage is input;

fig. 10 is a schematic structural diagram of a second switching circuit provided in an embodiment of the present application;

fig. 11 is a schematic structural diagram of a fourth power supply circuit provided in the embodiment of the present application;

fig. 12 is an equivalent circuit diagram of a second power circuit provided in an embodiment of the present application when a first voltage is input;

fig. 13 is an equivalent circuit diagram of a third power supply circuit provided in the embodiment of the present application when a second voltage is input;

fig. 14 is an equivalent circuit diagram of a fourth power supply circuit provided in the embodiment of the present application when a second voltage is input;

fig. 15 is a schematic structural diagram of a fifth power supply circuit provided in an embodiment of the present application;

fig. 16 is a schematic structural diagram of a sixth power supply circuit provided in an embodiment of the present application;

fig. 17 is a schematic structural diagram of a seventh power supply circuit according to an embodiment of the present application.

Wherein, the meanings represented by the reference numerals of the figures are respectively as follows:

10. a power supply circuit;

110. primary winding

112. A first primary winding;

114. a second primary winding;

122. a first secondary winding;

124. a second secondary winding;

130. a switching circuit;

142. a first rectifying circuit;

144. a second rectifying circuit;

150. a third rectifying circuit;

20. a load circuit.

Detailed Description

To make the objects, technical solutions and advantages of the present application more clear, embodiments of the present application will be described in further detail below with reference to the accompanying drawings.

It should be understood that reference to "a plurality" in this application means two or more. In the description of the present application, "/" means "or" unless otherwise stated, for example, a/B may mean a or B; "and/or" herein is only an association relationship describing an associated object, and means that there may be three relationships, for example, a and/or B, which may mean: a exists alone, A and B exist simultaneously, and B exists alone. In addition, for the convenience of clearly describing the technical solutions of the present application, the terms "first", "second", and the like are used to distinguish the same items or similar items having substantially the same functions and actions. Those skilled in the art will appreciate that the terms "first," "second," etc. do not denote any order or quantity, nor do the terms "first," "second," etc. denote any order or importance.

Before explaining the embodiments of the present application in detail, an application scenario of the embodiments of the present application will be described.

Transformers typically include a primary winding and a secondary winding wound on the same core. The primary winding is also called the primary coil, and the secondary winding is also called the secondary coil. Electromagnetic induction exists between the primary winding and the secondary winding. After voltage is input in the primary winding, voltage can be generated in the secondary winding, and the voltage ratio of the primary winding to the secondary winding is equal to the coil turn ratio of the primary winding to the secondary winding. The primary winding of the transformer can be connected with the mains supply, so that the mains supply voltage can be obtained. The secondary winding of the transformer may be connected to a load circuit, such as a power device, to supply power to the load circuit. When the mains voltage input by the primary winding of the transformer is not changed, the output voltage of the secondary winding can be adjusted by adjusting the duty ratio of the transformer. The duty ratio refers to the proportion of the time for which the primary side of the transformer transfers the electric energy to the secondary side of the transformer in a certain time period.

The mains voltage typically comprises both 110V (volts) and 220V. In the related art, when the commercial power voltage is switched between 110V and 220V, the voltage output from the transformer to the load circuit is usually kept unchanged by adjusting the duty ratio of the transformer. However, the working efficiency of the transformer is different under different duty ratios, and therefore, adjusting the duty ratio of the transformer affects the working state of the transformer, which is not beneficial to the transformer to output electric energy efficiently.

Therefore, the embodiment of the application provides a power circuit and a device, the connection mode between the first secondary winding and the second secondary winding of the transformer is changed through the switching circuit, and the output voltage of the power circuit can be kept unchanged on the premise of keeping the duty ratio of the transformer unchanged.

The power supply circuit provided in the embodiments of the present application is explained in detail below. In various embodiments of the present application, the connection between two electrical devices is referred to as an electrical connection. Here, the electrical connection means that two electrical devices are connected by wire or wireless to transmit an electrical signal.

Fig. 1 is a schematic structural diagram of a power supply circuit 10 according to an embodiment of the present disclosure. Referring to fig. 1, the power supply circuit 10 includes a transformer T and a switching circuit 130.

The transformer T includes a primary winding 110 and a secondary winding wound around the same core. In the embodiment of the present application, the transformer T includes two secondary windings. For 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, respectively. There is electromagnetic induction between the primary winding 110 and the first secondary winding 122 of the transformer T, and there is also 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 in series. The dotted terminal of transformer T is shown in fig. 1. The primary winding 110 may be connected to an ac power source such as a utility power source to provide ac power to the primary winding 110. The first secondary winding 122 and the second secondary winding 124 are 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.

In the present embodiment, the primary winding 110 can be connected to an ac power source. The ac power output from the ac power source to the primary winding 110 includes a first half-cycle and a second half-cycle within one cycle. The direction of current flow during the first half-cycle is opposite to the direction of current flow during the second half-cycle. According to the same-name end of the transformer T, the secondary winding N1 and the secondary winding N4 output voltage in the same half period; the secondary winding N2 and the secondary winding N3 output voltages in the same half period.

The switching circuit 130 is connected between the first secondary winding 122 and the load circuit 20, and 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, between the secondary winding N2 and the load circuit 20, between the secondary winding N3 and the load circuit 20, and between the secondary winding N4 and the load circuit 20. The switching circuit 130 is used to change the connection among the secondary winding N1, the secondary winding N2, the secondary winding N3, and the secondary winding N4. In one case, during the first half cycle, the secondary winding N1 and the secondary winding N4 may be connected in series via the switching circuit 130 and supply power to the load circuit 20; in the second half cycle described above, 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 first half cycle, the secondary winding N1 and the secondary winding N4 may be connected in parallel through the switching circuit 130 and supply power to the load circuit 20; in the second half cycle described above, 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.

For example, suppose the turn 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 turn ratio of the primary winding 110 to the secondary winding N1 is M, and the turn ratio of the primary winding 110 to the secondary winding N2 is M. The turn ratio of the primary winding 110 to the secondary winding N3 is M, and the turn ratio of the primary winding 110 to the secondary winding N4 is M. When the primary winding 110 is connected to the mains and the mains voltage is a first voltage (e.g. 110V): in the first half period of the first voltage, 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, 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 through 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 a second voltage (e.g. 220V): in the first half period of the second voltage, the secondary winding N1 and the secondary winding N4 are connected in parallel through 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.

When the mains voltage changes, the power 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 by the power circuit 10 to the load circuit 20 is kept unchanged. Therefore, the power supply circuit 10 can keep the voltage output from the power supply circuit 10 to the load circuit 20 unchanged without adjusting the duty ratio of the transformer T, thereby improving the turn ratio utilization rate of the transformer T in the power supply circuit 10 and improving the efficiency of the power supply circuit 10 for outputting electric energy.

It should be understood that, in the above description, the operation of the power supply circuit 10 according to the embodiment of the present application is explained only with the first voltage being 110V and the second voltage being 220V. In other embodiments, the first voltage and the second voltage may have other values, and the magnitudes of the first voltage and the second voltage do not limit the scope of protection of the present application.

Still referring to fig. 1, in 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 a first end of the first secondary winding 122. 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 connected secondary winding N1 and the first end of the secondary winding N2 together form the second end of the first secondary winding 122. The second end of the secondary winding N2 forms 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 a 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, which are connected together, together form the second end of the second secondary winding 124. The second end of the secondary winding N4 forms 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.

The load circuit 20 has an input terminal and an output terminal. In the embodiment of the present application, the first end of the first secondary winding 122 is connected to the input terminal of the load circuit 20, and the third end of the first secondary winding 122 is also connected to the input terminal 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. A first end of the second secondary winding 124 is connected to the output of the load circuit 20, and a third end of the second secondary winding 124 is also connected to the output 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.

Further, fig. 2 is a schematic structural diagram of another power supply circuit 10 provided in the embodiment of the present application. Referring to fig. 2, when the electrical signal required by the load circuit 20 is a direct current, the input terminal of the load circuit 20 is a positive terminal, and the output terminal of the load circuit 20 is a negative terminal. At this time, the power supply circuit 10 of the present application may further include a first rectification circuit 142 and a second rectification circuit 144. The first rectifying circuit 142 and the second rectifying circuit 144 rectify the alternating current output from the first secondary winding 122 and the second secondary winding 124.

Specifically, the first rectification circuit 142 has a first terminal, a second terminal, and a third terminal. A first end of the first rectifying circuit 142 is connected to a first end of the first secondary winding 122. A second terminal of the first rectifying circuit 142 is connected to a third terminal of the first secondary winding 122. The third terminal of the first rectifying circuit 142 is connected to the input terminal of the load circuit 20. The second rectification circuit 144 also has a first terminal, a second terminal, and a third terminal. A first end of the second rectifying circuit 144 is connected to an output end of the load circuit 20. A second terminal of the second rectification circuit 144 is connected to a first terminal of the second secondary winding 124. The third terminal of the second rectifying circuit 144 is connected to the third terminal of the second secondary winding 124.

Further, as shown in fig. 2, the first rectification circuit 142 includes a diode D1 and a diode D2. The second rectification circuit 144 includes a diode D3 and a diode D4.

Specifically, the anode of the diode D1 constitutes a first end of the first rectification 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 a second terminal of the first rectifying circuit 142. That is, the anode of the diode D2 is connected to the third terminal of the first secondary winding 122, i.e., the anode of the diode D2 is connected to the second terminal of the secondary winding N2. The cathode of the diode D1 and the cathode of the diode D2 are connected together to form a third terminal of the first rectifying circuit 142. That is, the cathode of the diode D1 and the cathode of the diode D2 are both connected to the input terminal of the load circuit 20.

The anode of the diode D3 and the anode of the diode D4 are connected together to constitute a first terminal of the second rectifying circuit 144. That is, the anode of the diode D3 and the anode of the diode D4 are both connected to the output terminal of the load circuit 20. The cathode of the diode D3 constitutes a second terminal of the second rectifying 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 terminal of the second rectifying 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.

Still referring to fig. 2, in some embodiments, the primary winding 110 of the transformer T may also include a first primary winding 112 and a second primary winding 114. The first primary winding 112 is used for electromagnetic induction with the first secondary winding 122. The second primary winding 114 is for electromagnetic induction with the second secondary winding 124. The first primary winding 112 and the second primary winding 114 may be connected in series with an ac power source or in parallel with the ac power source, which is not limited herein. 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 a first voltage, that is, 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, which means that the first primary winding 112 and the second primary winding 114 both input the second voltage.

The following describes an implementation of the switching circuit 130 in the power supply circuit 10 according to the present application with reference to an embodiment.

In a first possible manner, fig. 3 is a schematic structural diagram of a switching circuit 130 provided in an embodiment of the present application, and fig. 4 is a schematic structural diagram of a power supply circuit 10 including the switching circuit 130 shown in fig. 3. Referring to fig. 3 and 4, the switching circuit 130 has a first terminal, a second terminal, a third terminal and a fourth terminal. A first terminal of the switching circuit 130 is connected to a second terminal of the first secondary winding 122. A second terminal of the switching circuit 130 is connected to a second terminal of the second secondary winding 124. The third terminal of the switching circuit 130 is connected to the input terminal of the load circuit 20. A fourth terminal of the switching circuit 130 is connected to an output terminal of the load circuit 20.

Specifically, the switching circuit 130 includes a switching device K1 and a switching device K2. Wherein the switching device K1 includes a first contact, a second contact, and a third contact. A first contact of the switching device K1 is connected to the second end of the first secondary winding 122, and a first contact of the switching device K1 constitutes a first end of the switching circuit 130. A second contact of the switching device K1 is connected to the output of the load circuit 20, and a second contact of the switching device K1 forms a fourth terminal of the switching circuit 130. The switching device K2 also 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 and the third contact of the switching device K1 is also connected to the second end of the second secondary winding 124. In other words, the first contact of the switching device K2 and the third contact of the switching device K1 together constitute the second terminal of the switching circuit 130. The second contact of the switching device K2 is connected to the input of the load circuit 20, and the second contact of the switching device K2 forms the third terminal of the switching circuit 130. The third contact of the switching device K2 is connected to the second end of the first secondary winding 122, i.e., to the first contact of the switching device K1.

When the primary winding 110 inputs a first voltage (e.g., 110V), as shown in fig. 5, 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. At this time, an equivalent circuit diagram of the power supply circuit 10 is shown in fig. 6. Referring to fig. 6, in operation of the power circuit 10, during a first half-cycle of the first voltage, the flow direction of the electrical signal is: the electrical signal output from 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 through a diode D4. A first end of the secondary winding N4 is connected to a second end of the secondary winding N1 via a switching circuit 130 (equivalently, a wire in fig. 6). At this time, the secondary winding N1 and the secondary winding N4 are connected in series via the switching circuit 130, and power is supplied to the load circuit 20.

In the second half of the first voltage, the electrical signal flows as: the electrical signal output from 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 through a diode D3. The second terminal of the secondary winding N3 is connected to the first terminal of the secondary winding N2 via the switching circuit 130 (equivalently, a wire in fig. 6). At this time, the secondary winding N2 and the secondary winding N3 are connected in series via the switching circuit 130, and power is supplied to the load circuit 20.

When the primary winding 110 inputs a second voltage (e.g., 220V), as shown in fig. 7, 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. At this time, the equivalent circuit diagrams of the power supply circuit 10 are shown in fig. 8 and 9. Referring to fig. 8, in operation of the power circuit 10, during the first half-cycle of the second voltage, the flow direction of the electrical signal is: the electrical signal output from the secondary winding N1 is rectified by the diode D1 and input to the load circuit 20. The electrical signal output from the load circuit 20 flows back to the secondary winding N1 via the switching circuit 130 (equivalently, a wire in fig. 8). Meanwhile, the electrical signal output from the secondary winding N4 is input to the load circuit 20 via the switching circuit 130 (equivalently, a wire in fig. 8). The electrical signal output by the load circuit 20 is rectified by the diode D4 and flows back to the secondary winding N4. At this time, the secondary winding N1 and the secondary winding N4 are connected in parallel by the switching circuit 130, and power is supplied to the load circuit 20.

Referring to fig. 9, in the operation of the power circuit 10, during the second half period of the second voltage, the flow direction of the electrical signal is: the electrical signal output from the secondary winding N2 is rectified by the diode D2 and input to the load circuit 20. The electrical signal output from the load circuit 20 flows back to the secondary winding N2 via the switching circuit 130 (equivalently, a wire in fig. 8). Meanwhile, the electrical signal output from the secondary winding N3 is input to the load circuit 20 via the switching circuit 130 (equivalently, a wire in fig. 8). The electrical signal output by the load circuit 20 is rectified by the diode D3 and flows back to the secondary winding N3. At this time, the secondary winding N2 and the secondary winding N3 are connected in parallel by the switching circuit 130, and power is supplied to the load circuit 20.

Further, the switching device K1 and the switching device K2 may be manually controlled. The user manually controls the switching device K1 to enable the second contact or the third contact of the switching device K1 to be connected with the first contact; the switching device K2 is manually controlled such that the second contact or the third contact of the switching device K2 is connected to the first contact. The power circuit 10 may also include a controller that senses the magnitude of the input voltage to the primary winding 110. When the controller detects that the primary winding 110 inputs the first voltage, the controller controls the first contact of the switching device K1 to be connected with the third contact, and controls the first contact of the switching device K2 to be connected with the third contact. When the controller detects that the primary winding 110 inputs the second voltage, the controller controls the first contact and the second contact of the switching device K1 to be connected, and controls the first contact and the second contact of the switching device K2 to be connected.

In a second possible manner, fig. 10 is a schematic structural diagram of a switching circuit 130 provided in an embodiment of the present application, and fig. 11 is a schematic structural diagram of a power supply circuit 10 including the switching circuit 130 shown in fig. 10. Referring to fig. 10 and 11, the switching circuit 130 has a first terminal, a second terminal, a third terminal and a fourth terminal. A first terminal of the switching circuit 130 is connected to a second terminal of the first secondary winding 122. A second terminal of the switching circuit 130 is connected to a second terminal of the second secondary winding 124. The third terminal of the switching circuit 130 is connected to the input terminal of the load circuit 20. The fourth terminal of the switching circuit 130 is connected to the output terminal of the load circuit 20.

Specifically, the switching circuit 130 includes a transistor VT1, a diode D5, a diode D6, and a diode D7. The transistor VT1 has a control terminal, a first terminal, and a second terminal. A first terminal of the transistor VT1 is connected to the second terminal of the first secondary winding 122, and a first terminal of the transistor VT1 constitutes a first terminal of the switching circuit 130. A second terminal of the transistor VT1 is connected to a second terminal of the second secondary winding 124, and a second terminal of the transistor VT1 constitutes a second terminal of the switching circuit 130. The control terminal of the transistor VT1 is used to control the on/off between the first terminal and the second terminal of the transistor VT 1. An anode of the diode D5 is connected to the second terminal of the transistor VT 1. The cathode of the diode D5 is connected to the input terminal of the load circuit 20, and the cathode of the diode D5 forms the third terminal of the switching circuit 130. The anode of the diode D6 is connected to the output terminal of the load circuit 20, and the anode of the diode D6 forms the fourth terminal of the switching circuit 130. The cathode of the diode D6 is connected to a first terminal of the transistor VT 1. An anode of the diode D7 is connected to the first terminal of the transistor VT1, and a cathode of the diode D7 is connected to the second terminal of the transistor VT 1. The diode D7 is a parasitic diode of the transistor VT1, and is used to prevent the high voltage from breaking down the transistor VT1, so as to achieve the free-wheeling effect.

When the primary winding 110 inputs a first voltage (e.g., 110V), the control terminal of the transistor VT1 controls the conduction between the first terminal and the second terminal of the transistor VT 1. At this time, an equivalent circuit diagram of the power supply circuit 10 is shown in fig. 12. Referring to fig. 12, in operation of the power circuit 10, during a first half-cycle of the first voltage, the flow direction of the electrical signal is: the electrical signal output from 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 through a diode D4. The first terminal of the secondary winding N4 is connected to the second terminal 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 via 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 terminal of the load circuit 20, and the voltage of the anode of the diode D6 is equal to the voltage of the second terminal of the secondary winding N4; the cathode of the diode D6 is connected to the first terminal of the secondary winding N4 through the transistor VT1, and the voltage of the cathode of the diode D6 is equal to the voltage of the first terminal of the secondary winding N4, so that the diode D6 is turned off. The anode of the diode D5 is connected with the first end of the secondary winding N4, and the voltage of the anode of the diode D5 is equal to the voltage of the first end of the secondary winding N4; the cathode of the diode D5 is connected to the input terminal of the load circuit 20, and the voltage at the cathode of the diode D5 is equal to the voltage at the first terminal of the secondary winding N1, so that the diode D5 is turned off.

In the second half of the first voltage, the electrical signal flows as: the electrical signal output from 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 through a diode D3. The second terminal of the secondary winding N3 is connected to the first terminal 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 via 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 terminal of the load circuit 20, and the voltage of the anode of the diode D6 is equal to the voltage of the first terminal 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 of the cathode of the diode D6 is equal to the voltage of the second end of the secondary winding N3, so that the diode D6 is turned off. The anode of the diode D5 is connected with the second end of the secondary winding N3, and the voltage of the anode of the diode D5 is equal to the voltage of the second end of the secondary winding N3; the cathode of the diode D5 is connected to the input of the load circuit, and the voltage at the cathode of the diode D5 is equal to the power supply at the second end of the secondary winding N2, so that the diode D5 is turned off.

When the primary winding 110 inputs a second voltage (e.g., 220V), the control terminal of the transistor VT1 controls the first terminal and the second terminal of the transistor VT1 to be disconnected. At this time, the equivalent circuit diagrams of the power supply circuit 10 are shown in fig. 13 and 14. Referring to fig. 13, in operation of the power circuit 10, during the first half-cycle of the second voltage, the flow direction of the electrical signal is: the electrical signal output from 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 flows back to the secondary winding N1 via the diode D6 in the switching circuit 130. Meanwhile, the electrical signal output from the secondary winding N4 is input to the load circuit 20 via the diode D5 in the switching circuit 130. The electrical signal output by the load circuit 20 is rectified by the diode D4 and flows back to the secondary winding N4. At this time, the secondary winding N1 and the secondary winding N4 are connected in parallel by the switching circuit 130, and power is supplied to the load circuit 20.

Referring to fig. 14, in operation of the power circuit 10, during the second half period of the second voltage, the flow direction of the electrical signal is: the electrical signal output from 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 flows back to the secondary winding N2 via the diode D6 in the switching circuit 130. Meanwhile, the electrical signal output from the secondary winding N3 is input to the load circuit 20 via the diode D5 in the switching circuit 130. The electrical signal output by the load circuit 20 is rectified by the diode D3 and flows back to the secondary winding N3. At this time, the secondary winding N2 and the secondary winding N3 are connected in parallel by the switching circuit 130, and power is supplied to the load circuit 20.

Further, the transistor VT1 may be manually controlled. That is, the user manually inputs the first level signal to the control terminal of the transistor VT1 to make the first terminal and the second terminal of the transistor VT1 conduct; or the user manually inputs a second level signal to the control terminal of the transistor VT1 to disconnect the first terminal and the second terminal of the transistor VT 1. The power circuit 10 may also include a controller that senses the magnitude of the input voltage to the primary winding 110. When the controller detects that the primary winding 110 inputs the first voltage, the controller inputs a first level signal to the control terminal of the transistor VT1, so that the first terminal and the second terminal of the transistor VT1 are turned on. When the controller detects that the primary winding 110 inputs the second voltage, the controller inputs a second level signal to the control terminal of the transistor VT1, so that the first terminal and the second terminal of the transistor VT1 are disconnected. The first level signal is one of a low level signal and a high level signal, and the second level signal is the other one of the low level signal and the high level signal. The levels of the first level signal and the second level signal depend on the type of the transistor VT 1.

In the power supply circuit 10, when a first voltage is input to the primary winding 110, in a first half period 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; during the second half-cycle of the first voltage, the secondary winding N2 and the secondary winding N3 supply power in series through the switching circuit 130 to the load circuit 20. 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, 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 first half period of the second voltage; during the second half cycle of the second voltage, the secondary winding N2 and the secondary winding N3 supply power in parallel to the load circuit 20 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 rectification circuit. In the power supply circuit 10, no matter the first voltage or the second voltage is input, the first secondary winding 122, the second secondary winding 124, the diode D1, the diode D2, the diode D3, and the diode D4 are all in the working state all the time, so that the utilization rate of devices in the power supply circuit 10 is improved, and the service life of the power supply circuit 10 can be prolonged. In the power supply circuit 10, the diode D1, the diode D2, the diode D3 and the diode D4 may use diodes having the same withstand voltage, so that the material cost of the power supply circuit 10 may be reduced, and the power loss may be reduced.

Further, in the present application, the Transistor VT1 may be a BJT (Bipolar Junction Transistor) or MOS (Metal Oxide Semiconductor) Transistor. The Bipolar Transistor may also be an IGBT (Insulated Gate Bipolar Transistor).

Fig. 15 is a schematic structural diagram of another power supply circuit 10 according to an embodiment of the present disclosure. Referring to fig. 15, in some embodiments, the power circuit 10 of the present application further includes a third rectification circuit 150.

Specifically, the third rectification circuit 150 has a first terminal, a second terminal, and a third terminal. A first end of the third rectifying circuit 150 is connected to a first end of the first secondary winding 122, and a first end of the third rectifying circuit 150 is connected to a third end of the first secondary winding 122. A second terminal of the third rectification circuit 150 is connected to an input terminal of the load circuit 20. A third terminal of the third rectifying circuit 150 is connected to the output terminal of the load circuit 20, and a third terminal of the third rectifying circuit 150 is connected to a first terminal of the second secondary winding 124 and a third terminal of the second secondary winding 124. In the power supply circuit 10, the third rectifying circuit 150 can further rectify the electric signal input to the load circuit 20, thereby further stabilizing the electric signal input to the load circuit 20.

Further, fig. 16 and 17 show a circuit configuration diagram of the third rectification circuit 150. Referring to fig. 16 and 17, the third rectification circuit 150 includes: inductance L1 and capacitance C1. A first terminal of the inductor L1 is connected to a first terminal of the first secondary winding 122, and a first terminal of the inductor L1 is connected to a third terminal of the first secondary winding 122. A second terminal of inductor L1 is coupled to an input terminal of load circuit 20. The first plate of the capacitor C1 is connected to the second terminal of the inductor L1. The second plate of the capacitor C1 is connected to the output of the load circuit 20. 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.

Referring to fig. 16, when the switching circuit 130 includes the switching device K1 and the switching device K2, as is known from the above description, the second contact of the switching device K2 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 second contact of the switching device K2 is connected to the first terminal of the inductor L1. The second contact of the switching device K1 constitutes a fourth terminal of the switching circuit 130. In the present embodiment, the second contact of the switching device K1 is connected to the output terminal of the load circuit 20, and the second contact of the switching device K1 is connected to the second plate of the capacitor C1.

Referring to fig. 17, when the switching circuit 130 includes the transistor VT1, the diode D5, the diode D6 and the diode D7, as 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 L1. The anode of the diode D6 forms 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 C1.

In the embodiment of the present application, the power supply circuit 10 includes a transformer T and a switching circuit 130. The transformer T includes a primary winding 110, a first secondary winding 122, and a second secondary winding 124. The first secondary winding 122 includes a secondary winding N1 and a secondary winding N2 in series. The second secondary winding 124 includes a secondary winding N3 and a secondary winding N4 in series. The switching circuit 130 is connected between the first secondary winding 122 and the load circuit 20, and between the second secondary winding 124 and the load circuit 20. The primary winding 110 may be connected to mains electricity. When the power supply circuit 10 is in operation, 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; during the second half-cycle of the first voltage, the secondary winding N2 and the secondary winding N3 supply power in series through the switching circuit 130 to the load circuit 20. If the mains voltage is the second voltage of 220V, the secondary winding N1 and the secondary winding N4 supply power to the load circuit 20 in parallel through the switching circuit 130 during the first half cycle of the second voltage; during a second half-cycle of the second voltage, the secondary winding N2 and the secondary winding N3 supply power in parallel to the load circuit 20 through the switching circuit 130. When the mains voltage changes, the power 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 by the power circuit 10 to the load circuit 20 is kept unchanged. Therefore, the power supply circuit 10 can keep the voltage output from the power supply circuit 10 to the load circuit 20 unchanged without adjusting the duty ratio of the transformer T, and the turn ratio utilization rate of the transformer in the power supply circuit 10 is improved, so that the efficiency of the power supply circuit 10 for outputting electric energy can be improved. According to the power circuit 10, no matter 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 all in the working state all the time, so that the utilization rate of devices in the power circuit 10 is improved, and the service life of the power circuit 10 can be prolonged. In the power supply circuit 10, the diode D1, the diode D2, the diode D3 and the diode D4 may use diodes having the same withstand voltage, so that the material cost of the power supply circuit 10 may be reduced, and the power loss may be reduced.

The embodiment of the present application also provides a power supply apparatus, which includes the power supply circuit 10 in any one of the above embodiments.

Specifically, the power supply circuit 10 includes a transformer T and a switching circuit 130. The transformer T includes a primary winding 110, a first secondary winding 122, and a second secondary winding 124. The first secondary winding 122 includes a secondary winding N1 and a secondary winding N2 in series. The second secondary winding 124 includes a secondary winding N3 and a secondary winding N4 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 the 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 the 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.

In some embodiments, the first secondary winding 122 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 122. 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 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 and third terminals of the first secondary winding 122 are each connected to an input of the load circuit 20.

The second secondary winding 124 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 124. 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 form 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 and third terminals of the second secondary winding 124 are connected to the output terminal of the load circuit 20.

In some embodiments, the power supply circuit 10 further comprises: a first rectifying circuit 142 and a second rectifying circuit 144.

A first end of the first rectifying circuit 142 is connected to a first end of the first secondary winding 122, and a second end of the first rectifying circuit 142 is connected to a third end of the first secondary winding 122. The third terminal of the first rectifying circuit 142 is connected to the input terminal of the load circuit 20.

A first terminal of the second rectifying circuit 144 is connected to the output terminal of the load circuit 20. A second terminal of the second rectifying circuit 144 is connected to a first terminal of the second secondary winding 124, and a third terminal of the second rectifying circuit 144 is connected to a third terminal of the second secondary winding 124.

In some embodiments, the first rectification circuit 142 includes: diode D1 and diode D2. The second rectification circuit 144 includes: diode D3 and diode D4.

The anode of the diode D1 is connected to the first end of the first secondary winding 122, and the cathode of the diode D1 is connected to the input of the load circuit 20.

The anode of the diode D2 is connected to the third end of the first secondary winding 122, and the cathode of the diode D1 is connected to the input of the load circuit 20.

The anode of the diode D3 is connected to the output of the load circuit 20, and the cathode of the diode D3 is connected to the first end of the second secondary winding 124.

The anode of the diode D4 is connected to the output terminal of the load circuit 20, and the cathode of the diode D4 is connected to the third terminal of the second secondary winding 124.

In some embodiments, the switching circuit 130 has a first terminal, a second terminal, a third terminal, and a fourth terminal.

A first terminal of the switching circuit 130 is connected to the second terminal of the first secondary winding 122, a second terminal of the switching circuit 130 is connected to the second terminal of the second secondary winding 124, a third terminal of the switching circuit 130 is connected to the input terminal of the load circuit 20, and a fourth terminal of the switching circuit 130 is connected to the output terminal of the load circuit 20.

In other embodiments, the switching circuit 130 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 122, the second contact of the switching device K1 is connected to the output terminal 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.

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 terminal 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.

When the first contact of the switching device K1 is connected with the second contact of the switching device K1, and the first contact of the switching device K2 is connected with the second contact of the switching device K2, the secondary winding N1 is connected in parallel with the secondary winding N4, and the secondary winding N2 is connected in parallel with the secondary winding N3. 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.

In some embodiments, the switching circuit 130 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 122, and the second terminal of the transistor VT1 is connected to the second terminal of the second secondary winding 124.

An anode of the diode D5 is connected to the second terminal of the transistor VT1, and a cathode of the diode D5 is connected to the input terminal of the load circuit 20.

An anode of the diode D6 is connected to the output terminal of the load circuit 20, and a cathode of the diode D6 is connected to the first terminal of the transistor VT 1.

An anode of the diode D7 is connected to the first terminal of the transistor VT1, and a cathode of the diode D7 is connected to the second terminal of the transistor VT 1.

When the first end of the transistor VT1 is conducted with the second end of the transistor VT1, the secondary winding N1 is connected in series with the secondary winding N4, and the secondary winding N2 is connected in series with the secondary winding N3. When the first terminal of the transistor VT1 is disconnected from the second terminal of the transistor VT1, the secondary winding N1 is connected in parallel with the secondary winding N4, and the secondary winding N2 is connected in parallel with the secondary winding N3.

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

The third rectification circuit 150 has a first terminal, a second terminal, and a third terminal. A first end of the third rectifying circuit 150 is connected to a first end of the first secondary winding 122, and a first end of the third rectifying circuit 150 is connected to a third end of the first secondary winding 122. A second terminal of the third rectification circuit 150 is connected to an input terminal of the load circuit 20. A third terminal of the third rectifying circuit 150 is connected to the output terminal of the load circuit 20, and a third terminal of the third rectifying circuit 150 is connected to a first terminal of the second secondary winding 124 and a third terminal of the second secondary winding 124.

In some embodiments, the third rectification circuit 150 includes: inductor L1 and capacitor C1.

A first terminal of the inductor L1 is connected to a first terminal of the first secondary winding 122, and a first terminal of the inductor L1 is connected to a third terminal of the first secondary winding 122. A second terminal of inductor L1 is coupled to an input terminal of load circuit 20.

A first plate of the capacitor C1 is connected to the second terminal of the inductor L1, a second plate of the capacitor C1 is connected to the output terminal of the load circuit 20, and a second plate of the capacitor C1 is connected to the first terminal of the second secondary winding 124 and the third terminal of the second secondary winding 124.

In the embodiment of the present application, the power supply circuit 10 includes a transformer T and a switching circuit 130. The transformer T includes a primary winding 110, a first secondary winding 122, and a second secondary winding 124. 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 in series. The switching circuit 130 is connected between the first secondary winding 122 and the load circuit 20, and between the second secondary winding 124 and the load circuit 20. The primary winding 110 may be connected to mains electricity. When the power supply circuit 10 is in operation, 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; during the second half-cycle of the first voltage, the secondary winding N2 and the secondary winding N3 supply power in series through the switching circuit 130 to the load circuit 20. If the mains voltage is a second voltage of 220V, the secondary winding N1 and the secondary winding N4 supply power to the load circuit 20 in parallel through the switching circuit 130 during a first half period of the second voltage; during the second half cycle of the second voltage, the secondary winding N2 and the secondary winding N3 supply power in parallel to the load circuit 20 through the switching circuit 130. When the mains voltage changes, the power 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 by the power circuit 10 to the load circuit 20 is kept unchanged. Therefore, the power supply circuit 10 can keep the voltage output from the power supply circuit 10 to the load circuit 20 unchanged without adjusting the duty ratio of the transformer T, thereby improving the turn ratio utilization rate of the transformer T in the power supply circuit 10 and improving the efficiency of the power supply circuit 10 for outputting electric energy.

The above-mentioned embodiments are only used for illustrating the technical solutions of the present application, and not for limiting the same; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; such modifications and substitutions do not substantially depart from the spirit and scope of the embodiments of the present application, and are intended to be included within the scope of the present application.

Claims

1. A power supply circuit, comprising: the transformer T comprises a primary winding, a first secondary winding and a second secondary winding;

when a second voltage is input to the primary winding, 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.

2. The power circuit of claim 1, wherein 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 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, 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; the first end and the third end of the first secondary winding are both connected with the input end of the load circuit;

3. The power supply circuit of claim 2, further comprising: a first rectifying circuit and a second rectifying circuit;

4. The power supply circuit according to claim 3, wherein the first rectification circuit includes: diode D1 and diode D2; the second rectification circuit includes: diode D3 and diode D4;

5. The power supply circuit of claim 2, wherein the switching circuit has a first terminal, a second terminal, a third terminal, and a fourth terminal;

6. The power supply circuit of claim 5, wherein the switching circuit comprises: switching device K1 and switching device K2;

when the first contact of the switching device K1 is connected with the second contact of the switching device K1, and the first contact of the switching device K2 is connected with the second contact of the switching device K2, the secondary winding N1 is connected with the secondary winding N4 in parallel, and the secondary winding N2 is connected with the secondary winding N3 in parallel; when the first contact of the switching device K1 is connected with the third contact of the switching device K1, and the first contact of the switching device K2 is connected with the third contact of the switching device K2, the secondary winding N1 is connected with the secondary winding N4 in series, and the secondary winding N2 is connected with the secondary winding N3 in series.

7. The power supply circuit of claim 5, wherein the switching circuit comprises: a transistor VT1, a diode D5, a diode D6, and a diode D7;

8. The power supply circuit of claim 2, further comprising: a third rectifying circuit;

9. The power supply circuit according to claim 8, wherein the third rectification circuit includes: an inductor L1 and a capacitor C1;

10. A power supply device characterized by comprising a power supply circuit according to any one of claims 1 to 9.