CN215300503U - Switching power supply circuit - Google Patents
Switching power supply circuit Download PDFInfo
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- CN215300503U CN215300503U CN202121648013.1U CN202121648013U CN215300503U CN 215300503 U CN215300503 U CN 215300503U CN 202121648013 U CN202121648013 U CN 202121648013U CN 215300503 U CN215300503 U CN 215300503U
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Abstract
The utility model relates to a power supply circuit field. The utility model discloses a switching power supply circuit, including switching power supply circuit body and common mode inductance FL2, the switching power supply circuit body includes power control chip IC1 and feedback circuit, feedback circuit includes opto-coupler PC1, controllable accurate steady voltage source IC2 and bleeder circuit, the first end of common mode inductance FL2 connects the positive and negative output of switching power supply circuit body respectively, the second end of common mode inductance FL2 connects the positive and negative output of switching power supply circuit respectively, the input end of bleeder circuit connects the positive output of switching power supply circuit, the output end of bleeder circuit connects the reference end of controllable accurate steady voltage source IC2, the negative pole of the controllable precise voltage-stabilizing power supply IC2 is sequentially connected with the primary pole of the optocoupler PC1 in series and the resistor is connected with the positive output end of the switching power supply circuit body, the anode of the controllable precise voltage-stabilizing power supply IC2 is grounded, and the secondary of the optocoupler PC1 is connected between the feedback signal input end of the power supply control chip IC1 and the ground. The utility model discloses an output voltage ripple is little, and output power supply stability is good, the high quality.
Description
Technical Field
The utility model belongs to the power supply circuit field specifically relates to a switching power supply circuit.
Background
The switch power supply is a power supply which utilizes the modern power electronic technology to control the time proportion of the on and off of a switch tube and maintain stable output voltage. The switching power supply has the advantages of simple structure, small size, light weight, high efficiency and convenience in use, and is widely applied to the fields of industrial automation control, military equipment, scientific research equipment, LED illumination, industrial control equipment, communication equipment, power equipment, computer cases, digital products and the like.
In some fields, the requirement for the ripple of the dc voltage output by the switching power supply is relatively high, and the ripple of the dc voltage to be output is relatively small, but most of the conventional switching power supplies have less ideal processing on the output ripple and relatively large output ripple, and although some switching power supplies with relatively small output ripple have the disadvantages of relatively complex circuit and relatively high cost.
Disclosure of Invention
An object of the utility model is to provide a switching power supply circuit that output ripple is little is used for solving the technical problem that above-mentioned exists.
In order to achieve the above object, the utility model adopts the following technical scheme: a switch power supply circuit comprises a switch power supply circuit body and a common mode inductor FL2, wherein the switch power supply circuit body comprises a power supply control chip IC1 and a feedback circuit, the feedback circuit comprises an optical coupler PC1, a controllable precise voltage-stabilizing source IC2 and a voltage division circuit, the first end of the common mode inductor FL2 is respectively connected with the positive and negative output ends of the switch power supply circuit body, the second end of the common mode inductor FL2 is respectively connected with the positive and negative output ends of the switch power supply circuit, the input end of the voltage division circuit is connected with the positive output end of the switch power supply circuit, the output end of the voltage division circuit is connected with the reference end of the controllable precise voltage-stabilizing source IC2, the negative electrode of the controllable precise voltage-stabilizing source IC2 is sequentially connected with the primary end and the resistor of the optical coupler PC1 in series and connected with the positive output end of the switch power supply circuit body, the positive electrode of the controllable precise voltage-stabilizing source IC2 is grounded, and the secondary electrode of the optical coupler PC1 is connected between the feedback signal input end of the power supply control chip IC1 and the ground.
Furthermore, the common-mode inductor further comprises an electrolytic capacitor EC5 and a resistor R17, wherein the electrolytic capacitor EC5 and the resistor R17 are connected in parallel and then connected between the second ends of the common-mode inductors FL 2.
Furthermore, the voltage dividing circuit comprises resistors R21, R22 and R23, the first end of the resistor R21 is connected with the positive output end of the switching power supply circuit, the second end of the resistor R21 is connected with the resistor R22 in series and is grounded, the resistor R23 is connected with the resistor R22 in parallel, and the node between the resistors R21 and R22 is connected with the reference end of the controllable precise voltage-stabilizing source IC 2.
Further, the device also comprises a resistor R19, and a resistor R19 is arranged in parallel with the primary of the optocoupler PC 1.
Furthermore, the optical coupler PC1 is a phototriode output type optical coupler.
Still further, still include electric capacity C2, electric capacity C2 sets up with the secondary of opto-coupler PC1 in parallel.
Further, the model of the power control chip IC1 is OB 2281A.
Furthermore, the switching power supply circuit body is an isolated switching power supply circuit body.
Further, the controllable precision voltage stabilizing source IC2 is of the model number TL 431.
The utility model has the advantages of:
the utility model discloses the direct voltage ripple of output is little, and output power supply stability is good, the high quality, and circuit structure is simple, easily realizes, and is with low costs.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.
Fig. 1 is a circuit diagram of an embodiment of the present invention.
Detailed Description
To further illustrate the embodiments, the present invention provides the accompanying drawings. The accompanying drawings, which are incorporated in and constitute a part of this disclosure, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the embodiments. With these references, one of ordinary skill in the art will appreciate other possible embodiments and advantages of the present invention. Elements in the figures are not drawn to scale and like reference numerals are generally used to indicate like elements.
The present invention will now be further described with reference to the accompanying drawings and detailed description.
As shown in FIG. 1, a switching power supply circuit comprises a switching power supply circuit body and a common mode inductor FL2, wherein the switching power supply circuit body comprises a power supply control chip IC1 and a feedback circuit, the feedback circuit comprises an optocoupler PC1, a controllable precision voltage-stabilizing source IC2 and a voltage dividing circuit, a first end of the common mode inductor FL2 is respectively connected with a positive output end V '+ and a negative output end V' -, a second end of the common mode inductor FL2 is respectively connected with a positive output end V + and a negative output end V-, an input end of the voltage dividing circuit is connected with a positive output end V + of the switching power supply circuit, an output end of the voltage dividing circuit is connected with a reference end of a controllable precision voltage-stabilizing source IC2, the negative pole of the controllable precise voltage-stabilizing source IC2 is connected in series with the primary of the optocoupler PC1 and the resistor R18 in turn and is connected with the positive output end V' +, of the switching power supply circuit body, the anode of the controllable precise voltage-stabilizing power supply IC2 is grounded, and the secondary of the optocoupler PC1 is connected between the feedback signal input end FB of the power control chip IC1 and the ground.
In this embodiment, the voltage divider circuit includes a resistor R21, an electrical resistor R22, and an electrical resistor R23, a first end of the resistor R21 is connected to a positive output terminal V + of the switching power supply circuit, a second end of the resistor R21 is connected in series with a resistor R22 and grounded, a resistor R23 is connected in parallel with the resistor R22, and a node between the resistor R21 and the resistor R22 is connected to a reference terminal of the controllable precision voltage regulator IC 2.
Preferably, in this embodiment, the controllable precision voltage regulator IC2 is model TL431, which is good in performance and low in cost, but not limited thereto, and in some embodiments, other controllable precision voltage regulators may be used.
Preferably, in this embodiment, the optocoupler PC1 is a phototriode output type optocoupler, the type is PC817, the performance is good, and the size is small. Of course, in some embodiments, the optocoupler PC1 may also be implemented using other optocouplers.
Further, in this specific implementation, the protection circuit further includes a resistor R19, and the resistor R19 is connected in parallel with a primary (light emitting diode) of the optocoupler PC1, so as to protect the primary of the optocoupler PC1, thereby improving safety and reliability. And a node between the resistor R21 and the resistor R22 is also sequentially connected with a capacitor C5 and a resistor R20 in series and is connected with the negative electrode of the controllable precise voltage-stabilizing power supply IC 2.
Further, in this specific implementation, the common-mode inductor further includes an electrolytic capacitor EC5 and a resistor R17, and the electrolytic capacitor EC5 and the resistor R17 are connected in parallel and then connected between the second end of the common-mode inductor FL2, so as to further filter the output voltage and reduce the output ripple.
In this embodiment, the switching power supply circuit body is an isolated switching power supply circuit body, and includes an input EMI circuit, a rectifying and filtering circuit, a high-frequency transformer TR, a power switching tube Q1, a power control chip IC1, an output circuit, and a feedback circuit. The input EMI circuit comprises a capacitor CX1 and a common-mode inductor FL1, the rectifying and filtering circuit comprises a rectifying bridge BD1 and an electrolytic capacitor EC1, the output circuit comprises a rectifying diode D5, an electrolytic capacitor EC4, a resistor R16 and a capacitor C4, the model of the power control chip IC1 is OB2281A, and the specific circuit connection please refer to FIG. 1 in detail, which is a mature switching power supply circuit and will not be described in detail.
Of course, in other embodiments, the switching power supply circuit body may also be implemented by using other existing switching power supply circuits.
Further, in this specific embodiment, a capacitor C2 is further included, and the capacitor C2 is connected in parallel with a secondary (phototransistor) of the optocoupler PC1, so as to further improve stability and reliability.
The working principle of the reduction of the output direct current voltage ripple is as follows:
when the output direct current voltage ripple is increased, the common mode inductor FL2 detects a ripple increasing signal, and a loop formed by the resistor R18 → the primary stage of the optical coupler PC1 → the controllable precise voltage-stabilizing source IC2 enables the primary stage conduction degree of the optical coupler PC1 to be strengthened, the secondary stage coupling of the optical coupler PC1 to be strengthened and the level to be reduced, the voltage of the feedback signal input end FB of the power control chip IC1 is reduced at the same time, the duty ratio of a PWM signal output by the power control chip IC1 is reduced, the conduction time of the power switch tube Q1 is also reduced, and therefore the output ripple is reduced.
The utility model discloses the direct voltage ripple of output is little, and output power supply stability is good, the high quality, and circuit structure is simple, easily realizes, and is with low costs.
While the invention has been particularly shown and described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.
Claims (9)
1. A switching power supply circuit characterized by: the switch power supply circuit comprises a switch power supply circuit body and a common-mode inductor FL2, wherein the switch power supply circuit body comprises a power supply control chip IC1 and a feedback circuit, the feedback circuit comprises an optocoupler PC1, a controllable precise voltage-stabilizing source IC2 and a voltage division circuit, the first end of the common-mode inductor FL2 is respectively connected with the positive and negative output ends of the switch power supply circuit body, the second end of the common-mode inductor FL2 is respectively connected with the positive and negative output ends of the switch power supply circuit, the input end of the voltage division circuit is connected with the positive output end of the switch power supply circuit, the output end of the voltage division circuit is connected with the reference end of the controllable precise voltage-stabilizing source IC2, the negative electrode of the controllable precise voltage-stabilizing source IC2 is sequentially connected with the primary side and the resistance of the optocoupler PC1 in series and is connected with the positive output end of the switch power supply circuit body, the positive electrode of the controllable precise voltage-stabilizing source IC2 is grounded, and the secondary side of the optocoupler PC1 is connected between the feedback signal input end of the power supply control chip IC1 and the ground.
2. The switching power supply circuit according to claim 1, wherein: the common-mode inductor FL comprises a common-mode inductor FL2, and is characterized by further comprising an electrolytic capacitor EC5 and a resistor R17, wherein the electrolytic capacitor EC5 and the resistor R17 are connected in parallel and then connected between the second ends of the common-mode inductor FL 2.
3. The switching power supply circuit according to claim 1, wherein: the voltage dividing circuit comprises resistors R21, R22 and R23, the first end of the resistor R21 is connected with the positive output end of the switching power supply circuit, the second end of the resistor R21 is connected with the resistor R22 in series and is grounded, the resistor R23 is connected with the resistor R22 in parallel, and the node between the resistors R21 and R22 is connected with the reference end of the controllable precise voltage-stabilizing source IC 2.
4. The switching power supply circuit according to claim 1, wherein: the circuit also comprises a resistor R19, wherein the resistor R19 is arranged in parallel with the primary of the optocoupler PC 1.
5. The switching power supply circuit according to claim 4, wherein: the optical coupler PC1 is a photosensitive triode output type optical coupler.
6. The switching power supply circuit according to claim 5, wherein: and the capacitor C2 is further included, and the capacitor C2 is arranged in parallel with the secondary of the optocoupler PC 1.
7. The switching power supply circuit according to claim 1, wherein: the model of the power supply control chip IC1 is OB 2281A.
8. The switching power supply circuit according to claim 1, wherein: the switch power supply circuit body is an isolated switch power supply circuit body.
9. The switching power supply circuit according to claim 1, wherein: the controllable precise voltage-stabilizing source IC2 is of the model number TL 431.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202121648013.1U CN215300503U (en) | 2021-07-20 | 2021-07-20 | Switching power supply circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202121648013.1U CN215300503U (en) | 2021-07-20 | 2021-07-20 | Switching power supply circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN215300503U true CN215300503U (en) | 2021-12-24 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202121648013.1U Active CN215300503U (en) | 2021-07-20 | 2021-07-20 | Switching power supply circuit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN215300503U (en) |
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2021
- 2021-07-20 CN CN202121648013.1U patent/CN215300503U/en active Active
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