An isolated power supply circuit

Abstract

The present application provides an isolated power supply circuit, including a common-mode inductor, having an input side and an output side, the input side being connected to an AC input voltage or a DC input voltage, and the output side having a first end and a second end; a first winding having a third end and a fourth end, the third end being connected to the first end; a second winding having a fifth end and a sixth end, the fifth end being connected to the second end; an AC power supply circuit connected between the third end and the fourth end, for providing AC power to the first winding; and a rectifier circuit connected between the fifth end and the sixth end, for converting AC power into DC power. The above-mentioned isolated power supply circuit can realize DC output without a separate transformer, thereby reducing the cost and volume of the circuit design, and the circuit design is simple and easy to implement.

Description

Technical Field

[0001] The present application mainly relates to the field of circuit design technology, and in particular to an isolated power supply circuit. Background Art

[0002] The existing power supply circuit is usually composed of a transformer and a rectifier circuit, wherein the transformer requires more components and has a more complicated design, resulting in the existing power supply circuit being complex, high in cost, and large in size. Summary of the invention

[0003] The purpose of the present application is to provide an isolated power supply circuit to solve at least one problem of the above-mentioned prior art.

[0004] To achieve the above objectives, in a first aspect, the present application provides an isolated power supply circuit, comprising:

[0005] A common mode inductor, having an input side and an output side, the input side being connected to an AC input voltage or a DC input voltage, and the output side having a first end and a second end;

[0006] A first winding having a third end and a fourth end, wherein the third end is connected to the first end;

[0007] a second winding having a fifth end and a sixth end, the fifth end being connected to the second end;

[0008] an AC power circuit, connected between the third end and the fourth end, and used for providing AC power to the first winding;

[0009] A rectifier circuit is connected between the fifth end and the sixth end, and is used for converting the alternating current into direct current.

[0010] In some embodiments, the common mode inductor includes a third winding and a fourth winding; the third winding and the fourth winding are connected in parallel; wherein,

[0011] The third winding is connected between the input side and the first end, and the fourth winding is connected between the input side and the second end.

[0012] In some embodiments, the AC power circuit includes:

[0013] Filter capacitor;

[0014] Wherein, the filter capacitor is connected in series between the fourth end and the sixth end.

[0015] In some embodiments, the rectifier circuit comprises:

[0016] Rectifier diode;

[0017] Wherein, the anode of the rectifier diode is connected to the fifth end, and the cathode of the rectifier diode is connected to the anode of the output of the rectifier circuit;

[0018] The sixth terminal and the negative electrode of the output of the rectifier circuit are both grounded.

[0019] In some embodiments, the rectifier circuit comprises:

[0020] a first rectifying diode and a second rectifying diode;

[0021] Wherein, the anode of the first rectifier diode is connected to the fifth end, and the cathode of the first rectifier diode is connected to the anode of the output of the rectifier circuit;

[0022] The anode of the second rectifier diode is connected to the sixth terminal, and the cathode of the second rectifier diode is connected to the anode of the output of the rectifier circuit;

[0023] The negative electrode of the output of the rectifier circuit is grounded.

[0024] In some embodiments, the second winding further has:

[0025] Center tap;

[0026] Wherein, the center tap is grounded.

[0027] In some embodiments, the rectifier circuit comprises:

[0028] Bridge rectifier;

[0029] The positive electrode of the bridge rectifier is connected to the positive electrode of the output of the rectifier circuit, and the negative electrode of the bridge rectifier is connected to the negative electrode of the output of the rectifier circuit.

[0030] In some embodiments, the rectifier circuit comprises:

[0031] Rectifier;

[0032] a first capacitor;

[0033] Linear regulators;

[0034] A second capacitor;

[0035] Wherein, the rectifier, the first capacitor and the second capacitor are connected in parallel to the second winding;

[0036] The linear regulator is connected between the positive electrode of the rectifier and the positive electrode of the output of the rectifier circuit, and the negative electrode of the rectifier is connected to the negative electrode of the output of the rectifier circuit.

[0037] In some embodiments, the rectifier is a half-wave rectifier or a full-wave rectifier.

[0038] Compared with the prior art, the advantages of the above-mentioned isolated power supply circuit are:

[0039] Voltage conversion on the AC side is achieved through the common-mode inductor, the first winding and the second winding, and rectification is achieved through the rectifier circuit, so that DC output can be achieved in the isolated power supply circuit, thereby eliminating the need for a separate transformer, reducing the cost and volume of the circuit design, and the circuit design is simple and easy to implement. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The accompanying drawings are included to provide a further understanding of the present application. They are included and constitute a part of the present application. The accompanying drawings illustrate embodiments of the present application and together with the present specification serve to explain the principles of the present application. In the accompanying drawings:

[0041] Figure 1 is a simplified circuit diagram of an isolated power supply circuit provided by an exemplary embodiment of the present application;

[0042] Figure 2 is a specific circuit diagram of a first isolated power supply circuit provided by an exemplary embodiment of the present application;

[0043] Figure 3 An exemplary embodiment of the present application provides a specific circuit diagram of a second isolated power supply circuit;

[0044] Figure 4 An exemplary embodiment of the present application provides a specific circuit diagram of a third isolated power supply circuit;

[0045] Figure 5 An exemplary embodiment of the present application provides a specific circuit diagram of a fourth isolated power supply circuit;

[0046] Figure 6 FIG. 4 is a specific circuit diagram of a fifth isolated power supply circuit provided by an exemplary embodiment of the present application. DETAILED DESCRIPTION

[0047] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for the description of the embodiments. Obviously, the drawings described below are only some examples or embodiments of the present application. For ordinary technicians in this field, the present application can also be applied to other similar scenarios based on these drawings without creative work. Unless it is obvious from the language environment or otherwise explained, the same reference numerals in the figures represent the same structure or operation.

[0048] As shown in this application and claims, unless the context clearly indicates an exception, the words "a", "an", "an" and / or "the" do not refer to the singular and may also include the plural. Generally speaking, the terms "include" and "comprise" only indicate the inclusion of the steps and elements that have been clearly identified, and these steps and elements do not constitute an exclusive list. The method or device may also include other steps or elements.

[0049] In the description of the present application, it should be understood that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the device or element referred to must have a specific direction or be constructed and operated in a specific direction, and therefore cannot be understood as limiting the scope of protection of the present application; the directional words "inside and outside" refer to the inside and outside relative to the contours of each component itself.

[0050] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0051] In addition, it should be noted that the use of words such as "first" and "second" to define components is only for the convenience of distinguishing the corresponding components. If not otherwise stated, the above words have no special meaning and cannot be understood as limiting the scope of protection of this application. In addition, although the terms used in this application are selected from well-known and commonly used terms, some terms mentioned in the specification of this application may be selected by the applicant at his or her discretion, and their detailed meanings are explained in the relevant parts of the description of this article. In addition, it is required to understand this application not only by the actual terms used, but also by the meaning implied by each term.

[0052] It should be understood that when a component is referred to as being "on another component," "connected to another component," "coupled to another component," or "contacting another component," it may be directly on, connected to, coupled to, or contacting the other component, or there may be intervening components. In contrast, when a component is referred to as being "directly on another component," "directly connected to," "directly coupled to," or "directly contacting" another component, there are no intervening components. Similarly, when a first component is referred to as being "electrically in contact with" or "electrically coupled to" a second component, there is an electrical path between the first component and the second component that allows current to flow. The electrical path may include capacitors, coupled inductors, and / or other components that allow current to flow, even without direct contact between conductive components.

[0053] The purpose of the present application is to provide an isolated power supply circuit to solve the technical problems of the existing power supply circuit, such as complex circuit, high cost and large volume.

[0054] Figure 1 Schematic diagram of an isolated power supply circuit provided by the present application. Figure 1 As shown, the isolated power supply circuit 100 includes a common mode inductor 10, a first winding 20, a second winding 30, an AC power circuit 40 and a rectifier circuit 50. The common mode inductor 10 has an input side A and an output side B. Figure 1 As shown, the input side A refers to the left side of the common mode inductor 10, and the output side B refers to the right side of the common mode inductor 10. The output side B has a first end 1 and a second end 2. The first winding 20 has a third end 3 and a fourth end 4. The second winding 30 has a fifth end 5 and a sixth end 6.

[0055] In this embodiment, the third terminal 3 is connected to the first terminal 1. The fifth terminal 5 is connected to the second terminal 2. The AC power circuit 40 is connected between the third terminal 3 and the fourth terminal 4. The rectifier circuit 50 is connected between the fifth terminal 5 and the sixth terminal 6.

[0056] In the isolated power supply circuit 100, the input side A can be connected to an AC input voltage or a DC input voltage, and there is no limitation on this. The AC power circuit 40 is used to provide AC power to the first winding 20; and the rectifier circuit 50 is used to convert the AC power into DC power.

[0057] Exemplarily, other circuits outside the isolated power supply circuit 100 (such as the main circuit of the device) provide an AC input voltage or a DC input voltage at the input side A, and the present application does not impose any limitation on this.

[0058] The principle of the isolated power supply circuit 100 is to use a common-mode inductor 10, a first winding 20 and a second winding 30 to form a transformer, so that the first winding 20 is connected to the AC power circuit 40 to act as the primary side of the transformer (i.e., the side of the input voltage), and the second winding 30 is connected to the rectifier circuit 50 to act as the secondary side of the transformer (i.e., the side of the output voltage). In this way, a DC output can be easily obtained, thereby reducing the cost and volume of the circuit design, and the circuit design is simple and easy to implement.

[0059] It will be understood that the common mode inductor 10 can be, for example, a common mode inductor used in an existing power supply circuit to suppress common mode noise in the circuit. In some embodiments, these existing common mode inductors and two independent windings are used to form an isolated power supply circuit, and since no additional transformer is required, the cost and volume of the circuit design can be further reduced.

[0060] It will be understood that in the isolated power supply circuit 100 , the number of turns of the first winding 20 and the second winding 30 may be the same or different, and the present application does not impose any limitation on this.

[0061] In some embodiments, the common mode inductor includes a third winding and a fourth winding; the third winding and the fourth winding are connected in parallel; wherein the third winding is connected between the input side and the first end, and the fourth winding is connected between the input side and the second end.

[0062] In some embodiments, the AC power circuit includes: a filter capacitor; wherein the filter capacitor is connected in series between the fourth terminal and the sixth terminal.

[0063] In some embodiments, the rectifier circuit includes: a rectifier diode; wherein the anode of the rectifier diode is connected to the fifth terminal, and the cathode of the rectifier diode is connected to the anode of the output of the rectifier circuit; the sixth terminal and the cathode of the output of the rectifier circuit are both grounded.

[0064] In some embodiments, the rectifier circuit includes: a first rectifier diode and a second rectifier diode; wherein, the anode of the first rectifier diode is connected to the fifth terminal, and the cathode of the first rectifier diode is connected to the positive electrode of the output of the rectifier circuit; the anode of the second rectifier diode is connected to the sixth terminal, and the cathode of the second rectifier diode is connected to the positive electrode of the output of the rectifier circuit; the negative electrode of the output of the rectifier circuit is grounded.

[0065] In some embodiments, the second winding further has: a center tap; wherein the center tap is grounded.

[0066] In some embodiments, the rectifier circuit includes:

[0067] A bridge rectifier; wherein the positive electrode of the bridge rectifier is connected to the positive electrode of the output of the rectifier circuit, and the negative electrode of the bridge rectifier is connected to the negative electrode of the output of the rectifier circuit.

[0068] In some embodiments, the rectifier circuit includes: a rectifier; a first capacitor; a linear regulator; and a second capacitor; wherein the rectifier, the first capacitor, and the second capacitor are connected in parallel to the second winding; the linear regulator is connected between the positive electrode of the rectifier and the positive electrode of the output of the rectifier circuit, and the negative electrode of the rectifier is connected to the negative electrode of the output of the rectifier circuit.

[0069] In some embodiments, the rectifier is a half-wave rectifier or a full-wave rectifier.

[0070] The following will be combined Figure 2-Figure 6 The implementation method of this embodiment is described in detail. Example 1

[0071] Figure 2 This is a schematic diagram of the first isolated power supply circuit provided by the present application. Figure 2 The first isolated power supply circuit 100 includes a common mode inductor 10, a first winding 20, a second winding 30, an AC power supply circuit 40 and a rectifier circuit 50.

[0072] Specifically, the common mode inductor 10 includes a third winding 101 and a fourth winding 102; the third winding 101 and the fourth winding 102 are connected in parallel; wherein the third winding 101 is connected between the input side A and the first end 1, and the fourth winding 102 is connected between the input side A and the second end 2.

[0073] The AC power circuit 40 includes a filter capacitor 401 , wherein the filter capacitor 401 is connected in series between the fourth terminal 4 and the sixth terminal 6 .

[0074] The rectifier circuit 50 includes: a rectifier diode 501; wherein the positive electrode of the rectifier diode 501 is connected to the fifth terminal 5, and the negative electrode of the rectifier diode 501 is connected to the positive electrode of the output of the rectifier circuit; the sixth terminal 6 and the negative electrode of the output of the rectifier circuit 50 are both grounded 502. The rectifier diode 501 functions as a half-wave rectifier.

[0075] It will be understood that in the first isolated power supply circuit 100 , an AC input voltage is connected to the input side A. In this way, an AC output voltage can be obtained between the first terminal 1 and the second terminal 2 .

[0076] After analysis, the first isolated power supply circuit 100 performs voltage conversion through a transformer composed of a common mode inductor 10, a first winding 20 and a third winding 30. After half-wave rectification, an unstable DC output voltage DC can be obtained between the positive and negative poles of the output of the rectifier circuit 50. It can be seen that this circuit structure does not require a separate transformer, thereby reducing the cost and volume of the circuit design. Example 2

[0077] Figure 3This is a schematic diagram of the second isolated power supply circuit provided by the present application. Figure 3 The second isolated power supply circuit 100 includes a common mode inductor 10, a first winding 20, a second winding 30, an AC power supply circuit 40 and a rectifier circuit 50.

[0078] Specifically, the common mode inductor 10 includes a third winding 101 and a fourth winding 102; the third winding 101 and the fourth winding 102 are connected in parallel; wherein the third winding 101 is connected between the input side A and the first end 1, and the fourth winding 102 is connected between the input side A and the second end 2.

[0079] The AC power circuit 40 includes a filter capacitor 401 , wherein the filter capacitor 401 is connected in series between the fourth terminal 4 and the sixth terminal 6 .

[0080] The rectifier circuit 50 includes: a first rectifier diode 5011, a second rectifier diode 5012 and a ground 502. The anode of the first rectifier diode 5011 is connected to the fifth terminal 5, and the cathode of the first rectifier diode 5011 is connected to the anode of the output of the rectifier circuit 50; the anode of the second rectifier diode 5012 is connected to the sixth terminal 6, and the cathode of the second rectifier diode 5012 is connected to the anode of the output of the rectifier circuit 50; and the cathode of the output of the rectifier circuit 50 is grounded 502.

[0081] Continue to refer Figure 2 The second winding 30 is a winding having a center tap 301. The center tap 301 is grounded 502. The first rectifier diode 5011 and the second rectifier diode 5012 form a full-wave rectifier circuit to achieve full-wave rectification.

[0082] It will be understood that in the second isolated power supply circuit 100 , an AC input voltage is connected to the input side A. In this way, an AC output voltage can be obtained between the first terminal 1 and the second terminal 2 .

[0083] After analysis, the second isolated power supply circuit 100 performs voltage conversion through a transformer composed of a common mode inductor 10, a first winding 20 and a third winding 30. After full-wave rectification, an unstable DC output voltage DC can be obtained between the positive and negative poles of the output of the rectifier circuit 50. It can be seen that this circuit structure does not require a separate transformer, thereby reducing the cost and volume of the circuit design. Example 3

[0084] Figure 4 This is a schematic diagram of the third isolated power supply circuit provided by the present application. Figure 4 The third isolated power supply circuit 100 includes a common mode inductor 10 , a first winding 20 , a second winding 30 , an AC power supply circuit 40 and a rectifier circuit 50 .

[0085] Specifically, the common mode inductor 10 includes a third winding 101 and a fourth winding 102; the third winding 101 and the fourth winding 102 are connected in parallel; wherein the third winding 101 is connected between the input side A and the first end 1, and the fourth winding 102 is connected between the input side A and the second end 2.

[0086] The AC power circuit 40 includes a filter capacitor 401 , wherein the filter capacitor 401 is connected in series between the fourth terminal 4 and the sixth terminal 6 .

[0087] The rectifier circuit 50 includes a bridge rectifier 503. The positive electrode of the bridge rectifier 503 is connected to the positive electrode of the output of the rectifier circuit, and the negative electrode of the bridge rectifier 503 is connected to the negative electrode of the output of the rectifier circuit. The function of the bridge rectifier 503 is full-wave rectification.

[0088] By way of example and not limitation, the bridge rectifier 503 may be a rectifier composed of four diodes connected end to end.

[0089] It will be understood that in the third isolated power supply circuit 100 , an AC input voltage is connected to the input side A. In this way, an AC output voltage can be obtained between the first terminal 1 and the second terminal 2 .

[0090] After analysis, the third isolated power supply circuit 100 performs voltage conversion through a transformer composed of a common mode inductor 10, a first winding 20 and a third winding 30. After full-wave rectification, an unstable DC output voltage DC can be obtained between the positive and negative poles of the output of the rectifier circuit 50. It can be seen that this circuit structure does not require a separate transformer, thereby reducing the cost and volume of the circuit design. Example 4

[0091] Figure 5 This is a schematic diagram of the fourth isolated power supply circuit provided by the present application. Figure 5 The fourth isolated power supply circuit 100 includes a common mode inductor 10, a first winding 20, a second winding 30, an AC power supply circuit 40 and a rectifier circuit 50.

[0092] Specifically, the common mode inductor 10 includes a third winding 101 and a fourth winding 102; the third winding 101 and the fourth winding 102 are connected in parallel; wherein the third winding 101 is connected between the input side A and the first end 1, and the fourth winding 102 is connected between the input side A and the second end 2.

[0093] The AC power circuit 40 includes a filter capacitor 401 , wherein the filter capacitor 401 is connected in series between the fourth terminal 4 and the sixth terminal 6 .

[0094] The rectifier circuit 50 includes: a rectifier 504; a first capacitor 505; a linear regulator 506; and a second capacitor 507. The rectifier 504, the first capacitor 505, and the second capacitor 507 are connected in parallel to the second winding 30; the linear regulator 506 is connected between the positive electrode of the rectifier 504 and the positive electrode of the output of the rectifier circuit 50, and the negative electrode of the rectifier 504 is connected to the negative electrode of the output of the rectifier circuit 50. The first capacitor 505, the linear regulator 506, and the second capacitor 507 can play a role in voltage stabilization and filtering.

[0095] The rectifier 504 may be a half-wave rectifier or a full-wave rectifier, which is not limited.

[0096] It will be understood that in the fourth isolated power supply circuit 100 , an AC input voltage is connected to the input side A. In this way, an AC output voltage can be obtained between the first terminal 1 and the second terminal 2 .

[0097] After analysis, the fourth isolated power supply circuit 100 performs voltage conversion through a transformer composed of a common mode inductor 10, a first winding 20 and a third winding 30. After half-wave or full-wave rectification, a stable, low-ripple DC output voltage DC can be obtained between the positive and negative poles of the output of the rectifier circuit 50. It can be seen that this circuit structure does not require a separate transformer, thereby reducing the cost and volume of the circuit design. Example 5

[0098] Figure 6 This is a schematic diagram of the fifth isolated power supply circuit provided by the present application. Figure 6 The fifth isolated power supply circuit 100 includes a common mode inductor 10, a first winding 20, a second winding 30, an AC power supply circuit 40 and a rectifier circuit 50.

[0099] Specifically, the common mode inductor 10 includes a third winding 101 and a fourth winding 102; the third winding 101 and the fourth winding 102 are connected in parallel; wherein the third winding 101 is connected between the input side A and the first end 1, and the fourth winding 102 is connected between the input side A and the second end 2.

[0100] The AC power circuit 40 is connected between the third terminal 3 and the fourth terminal 4. The rectifier circuit 50 is connected between the fifth terminal 5 and the sixth terminal 6.

[0101] It will be understood that in the fifth isolated power supply circuit 100 , a DC input voltage is connected to the input side A. In this way, a DC output voltage DC can be obtained between the first terminal 1 and the second terminal 2 .

[0102] After analysis, the fifth isolated power supply circuit 100 performs voltage conversion through a transformer composed of a common mode inductor 10, a first winding 20 and a third winding 30. After rectification, an unstable DC output voltage DC can be obtained between the positive and negative poles of the output of the rectifier circuit 50. It can be seen that this circuit structure does not require a separate transformer, thereby reducing the cost and volume of the circuit design.

[0103] In summary, the above-mentioned isolated power supply circuit 100 utilizes the common-mode inductor 10, the first winding 20 and the second winding 30 to form a transformer, so that the first winding 20 is connected to the AC power supply circuit 40 to act as the primary side of the transformer (i.e., the side of the input voltage), and the second winding 30 is connected to the rectifier circuit 50 to act as the secondary side of the transformer (i.e., the side of the output voltage). In this way, a DC output can be easily obtained, thereby reducing the cost and volume of the circuit design, and the circuit design is simple and easy to implement.

[0104] The present application uses specific words to describe the embodiments of the present application. For example, "one embodiment", "an embodiment", and / or "some embodiments" refer to a certain feature, structure or characteristic related to at least one embodiment of the present application. Therefore, it should be emphasized and noted that "one embodiment" or "an embodiment" or "an alternative embodiment" mentioned twice or multiple times in different positions in this specification does not necessarily refer to the same embodiment. In addition, some features, structures or characteristics in one or more embodiments of the present application can be appropriately combined.

[0105] Similarly, it should be noted that in order to simplify the description of the disclosure of this application and thus help understand one or more application embodiments, in the above description of the embodiments of this application, multiple features are sometimes merged into one embodiment, figure or description thereof. However, this disclosure method does not mean that the features required by the object of this application are more than the features mentioned in the claims. In fact, the features of the embodiments are less than all the features of the single embodiment disclosed above.

[0106] In some embodiments, numbers describing the number of components and attributes are used. It should be understood that such numbers used for the description of the embodiments are modified by the modifiers "about", "approximately" or "substantially" in some examples. Unless otherwise specified, "about", "approximately" or "substantially" indicate that the numbers are allowed to vary by ±20%. Accordingly, in some embodiments, the numerical parameters used in the specification and claims are approximate values, which can be changed according to the required features of individual embodiments. In some embodiments, the numerical parameters should take into account the specified significant digits and adopt the method of general digit retention. Although the numerical domains and parameters used to confirm the breadth of the range in some embodiments of the present application are approximate values, in specific embodiments, the setting of such numerical values ​​is as accurate as possible within the feasible range.

[0107] Although the present application has been described with reference to the current specific embodiments, ordinary technicians in this technical field should recognize that the above embodiments are only used to illustrate the present application, and various equivalent changes or substitutions may be made without departing from the spirit of the present application. Therefore, as long as the changes and modifications to the above embodiments are within the essential spirit of the present application, they will fall within the scope of the claims of the present application.

Claims

1. An isolated power supply circuit, characterized in that: include: A common mode inductor, having an input side and an output side, the input side being connected to an AC input voltage or a DC input voltage, and the output side having a first end and a second end; A first winding having a third end and a fourth end, wherein the third end is connected to the first end; a second winding having a fifth end and a sixth end, the fifth end being connected to the second end; an AC power circuit, connected between the third end and the fourth end, and used for providing AC power to the first winding; A rectifier circuit is connected between the fifth end and the sixth end, and is used for converting the alternating current into direct current.

2. The isolated power supply circuit according to claim 1, characterized in that: The common mode inductor includes a third winding and a fourth winding; the third winding and the fourth winding are connected in parallel; wherein, The third winding is connected between the input side and the first end, and the fourth winding is connected between the input side and the second end.

3. The isolated power supply circuit according to claim 1, characterized in that: The AC power supply circuit comprises: Filter capacitor; Wherein, the filter capacitor is connected in series between the fourth end and the sixth end.

4. The isolated power supply circuit according to claim 1, characterized in that: The rectifier circuit comprises: Rectifier diode; Wherein, the anode of the rectifier diode is connected to the fifth end, and the cathode of the rectifier diode is connected to the anode of the output of the rectifier circuit; The sixth terminal and the negative electrode of the output of the rectifier circuit are both grounded.

5. The isolated power supply circuit according to claim 1, characterized in that: The rectifier circuit comprises: a first rectifying diode and a second rectifying diode; Wherein, the anode of the first rectifier diode is connected to the fifth end, and the cathode of the first rectifier diode is connected to the anode of the output of the rectifier circuit; The anode of the second rectifier diode is connected to the sixth terminal, and the cathode of the second rectifier diode is connected to the anode of the output of the rectifier circuit; The negative electrode of the output of the rectifier circuit is grounded.

6. The isolated power supply circuit according to claim 5, characterized in that: The second winding also has: Center tap; Wherein, the center tap is grounded.

7. The isolated power supply circuit according to claim 1, characterized in that: The rectifier circuit comprises: Bridge rectifier; The positive electrode of the bridge rectifier is connected to the positive electrode of the output of the rectifier circuit, and the negative electrode of the bridge rectifier is connected to the negative electrode of the output of the rectifier circuit.

8. The isolated power supply circuit according to claim 1, characterized in that: The rectifier circuit comprises: Rectifier; a first capacitor; Linear regulators; A second capacitor; Wherein, the rectifier, the first capacitor and the second capacitor are connected in parallel to the second winding; The linear regulator is connected between the positive electrode of the rectifier and the positive electrode of the output of the rectifier circuit, and the negative electrode of the rectifier is connected to the negative electrode of the output of the rectifier circuit.

9. The isolated power supply circuit according to claim 8, characterized in that: The rectifier is a half-wave rectifier or a full-wave rectifier.

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