CN217445258U - Forward switching power supply and output lossless absorption circuit thereof - Google Patents
Forward switching power supply and output lossless absorption circuit thereof Download PDFInfo
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- CN217445258U CN217445258U CN202221305330.8U CN202221305330U CN217445258U CN 217445258 U CN217445258 U CN 217445258U CN 202221305330 U CN202221305330 U CN 202221305330U CN 217445258 U CN217445258 U CN 217445258U
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B70/00—Technologies for an efficient end-user side electric power management and consumption
- Y02B70/10—Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes
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Abstract
The utility model relates to a forward switch power supply and an output lossless absorption circuit thereof, belonging to the switch power supply field; a forward switch power supply and its output lossless absorption circuit, including transformer T, transformer T has magnetic core, primary winding and secondary winding, the positive pole of rectifier diode D3 is connected with positive terminal of secondary winding, freewheeling diode D4 is connected with negative terminal of secondary winding, diode D1, diode D2 and electric capacity C1 are connected, make up the lossless absorption circuit of rectifier diode, the RC absorption circuit that adds on rectifier diode D3, freewheeling diode D4 in the prior art is replaced, not only reduced rectifier diode D3, the voltage stress of freewheeling diode D4, still greatly reduced the loss of the original parallel RC absorption circuit of rectifier diode D3, freewheeling diode D4 at the same time, has raised the conversion efficiency of the power supply, has reduced the calorific power of the power supply itself, have more practical value.
Description
Technical Field
The utility model relates to a just swash formula switching power supply and output nondestructive absorption circuit thereof belongs to the switching power supply field.
Background
As shown in fig. 1, forward or double-ended forward circuits are widely used in various switching power supplies. When the forward or double-end forward switching power supply works, a secondary rectifying diode and a secondary freewheeling diode have larger voltage spikes, which adversely affect the reliability of the power supply. In order to reduce the voltage peak of the rectifying/freewheeling diode, a mode of connecting an RC absorption circuit in parallel at two ends of the diode is traditionally adopted, because the working frequency of the switching power supply is above dozens of kH or hundreds of kHz, considerable loss can be generated on the RC absorption circuit, the overall loss of the power supply is increased, the working temperature rise of internal devices of the switching power supply is increased, and the reliability of the switching power supply is further reduced.
SUMMERY OF THE UTILITY MODEL
Utility model purpose: the forward switching power supply and the output lossless absorption circuit thereof are provided, the loss of the switching power supply is not additionally increased under the condition of reducing the voltage stress of a diode, and the problems that the conventional absorption circuit generates considerable loss on an RC absorption circuit because the working frequency of the switching power supply is more than dozens of kH or hundreds of kHz, the overall loss of the power supply is increased, the working temperature rise of internal devices of the switching power supply is increased, and the reliability of the switching power supply is further reduced are solved.
The technical scheme is as follows: in order to achieve the above object, an aspect of the present invention provides an output lossless absorption circuit of a forward switching power supply, including: transformer T, rectifier diode D3, freewheeling diode D4, output filter inductance L, output circuit and lossless absorption circuit.
Preferably, the lossless absorption circuit includes: diode D1, diode D2, capacitor C1;
preferably, one end of the capacitor C1 is connected to the cathode of the rectifier diode D3, the cathode of the freewheeling diode D4 and the pin No. 2 of the output filter inductor L, the other end of the capacitor C1 is connected to the anode of the diode D1 and the cathode of the diode D2, the anode of the diode D2 is connected to the anode of the freewheeling diode D4 and the cathode of the output circuit, and the cathode of the diode D1 is connected to the anode of the output circuit; at the moment when the primary switching tube is conducted, the impedances of the loop of the capacitor C1 and the diode D1 are smaller than that of the output filter inductor L, a low-impedance current leakage path is provided, the voltage stress of the freewheeling diode D4 can be greatly reduced, and the absorption loss is greatly reduced.
Preferably, the transformer T has a magnetic core, a primary winding and a secondary winding.
Preferably, the anode of the rectifier diode D3 is connected to the positive terminal of the secondary winding of the transformer T, and the freewheel diode D4 is connected to the negative terminal of the secondary winding of the transformer T.
Preferably, the output circuit includes: a filter capacitor CE and a resistor RL;
the No. 1 pin of the output filter inductor L is simultaneously connected with the cathode of the diode D1, the anode of the filter capacitor CE and the anode of the resistor RL; and the negative electrode of the filter capacitor CE is connected with the negative electrode of the resistor RL.
The utility model discloses two aspects provide a just swash formula switching power supply, a serial communication port, include just swash formula switching power supply's the harmless snubber circuit of output.
The utility model discloses following beneficial effect has at least:
1. the utility model discloses a just swash formula switching power supply output and can't harm absorption circuit, it is through with being used as absorptive RC traditional circuit among the prior art, changes traditional RC circuit into DDC absorption circuit, reduces the loss when can effectively satisfying the absorption high frequency burr during the use to guarantee just swash formula switching power supply reliable high-efficient work.
2. The forward switch power supply output lossless absorption circuit changes a circuit used as RC absorption in the prior art into a DDC lossless absorption circuit, so that the DDC lossless absorption circuit has smaller loss compared with an RC circuit for realizing the same function, is more convenient to reduce the voltage stress of a diode in output rectification and follow current and is beneficial to reducing the overall cost of the switch power supply.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the description below are only some embodiments described in the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.
Fig. 1 is a circuit diagram of an RC absorption circuit of a forward switching power supply output rectifying/freewheeling tube commonly used in the prior art.
Fig. 2 is a schematic diagram of the circuit structure of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments.
It will be understood that when an element is referred to as being "secured to" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "left," "right," and the like as used herein are for illustrative purposes only and do not represent the only embodiments.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.
The embodiment of the utility model provides a first aspect provides a harmless snubber circuit of forward switching power supply's output, under the condition that reduces diode voltage stress, does not additionally increase switching power supply's loss, include: the transformer T, the rectifier diode D3, the freewheeling diode D4, the output filter inductor L, the output circuit and the lossless absorption circuit;
the lossless absorption circuit includes: diode D1, diode D2, capacitor C1;
one end of the capacitor C1 is connected with the cathode of the rectifier diode D3, the cathode of the freewheeling diode D4 and the No. 2 pin of the output filter inductor L at the same time, the other end of the capacitor C1 is connected with the anode of the diode D1 and the cathode of the diode D2 at the same time, the anode of the diode D2 is connected with the anode of the freewheeling diode D4 and the cathode of the output circuit at the same time, and the cathode of the diode D1 is connected with the anode of the output circuit.
In the embodiment of the present invention, as shown in fig. 2, for the forward topology, when the primary switch tube is turned on, the rectifier diode D3 is turned on, the cathode voltage of the rectifier diode D3 is higher than the output voltage, the current on the rectifier diode D3 rises, the absorption current flows from the positive end of the secondary winding of the transformer T to the positive end of the output circuit through the rectifier diode D3, the capacitor C1, the diode D1, and after being filtered by the output filter capacitor CE, flows back to the secondary winding of the transformer T from the negative end of the output circuit, and the voltage of the capacitor C1 rises; when the primary switching tube is closed, the rectifier diode D3 is cut off, the output filter inductor L continues current through the output filter capacitor CE and the freewheeling diode D4, the current of the output filter inductor L decreases, the absorption capacitor C1 discharges through the output filter inductor L, the output capacitor CE and the diode D2, and the voltage of the capacitor C1 decreases. At the moment when the primary switch tube is switched on, the impedance of the capacitor C1 and the diode D1 loop is smaller than the impedance of the output filter inductor L, a low-impedance current leakage path is provided, the voltage stress of the freewheeling diode D4 can be greatly reduced, and the absorption loss is greatly reduced, so that the loss can be effectively reduced during working and using, and the voltage stress can be greatly reduced.
As a preferred embodiment of the present invention, the transformer T has a magnetic core, a primary winding and a secondary winding.
As a preferred embodiment of the present invention, the anode of the rectifier diode D3 is connected to the positive terminal of the secondary winding of the transformer T, and the freewheel diode D4 is connected to the negative terminal of the secondary winding of the transformer T.
As a preferred embodiment of the present invention, the output circuit includes: a filter capacitor CE and a resistor RL;
the No. 1 pin of the output filter inductor L is simultaneously connected with the cathode of the diode D1, the anode of the filter capacitor CE and the anode of the resistor RL;
and the negative electrode of the filter capacitor CE is connected with the negative electrode of the resistor RL.
The embodiment of the utility model provides a second aspect provides a just swash formula switching power supply, and this just swash formula switching power supply includes the just harmless snubber circuit of just swash formula switching power supply's that above-mentioned arbitrary embodiment provided output, can effectively reduce the loss through this output harmless snubber circuit, can reduce voltage stress by a wide margin simultaneously.
The preferred embodiments of the present invention have been described in detail with reference to the accompanying drawings, however, the present invention is not limited to the details of the above embodiments, and the technical concept of the present invention can be modified to perform various equivalent transformations, which all belong to the protection scope of the present invention.
Claims (5)
1. An output lossless snubber circuit for a forward switching power supply, comprising: the transformer T, the rectifier diode D3, the freewheeling diode D4, the output filter inductor L, the output circuit and the lossless absorption circuit;
the lossless absorption circuit includes: a diode D1, a diode D2, and a capacitor C1;
one end of the capacitor C1 is connected with the cathode of the rectifier diode D3, the cathode of the freewheeling diode D4 and the No. 2 pin of the output filter inductor L at the same time, the other end of the capacitor C1 is connected with the anode of the diode D1 and the cathode of the diode D2 at the same time, the anode of the diode D2 is connected with the anode of the freewheeling diode D4 and the cathode of the output circuit at the same time, and the cathode of the diode D1 is connected with the anode of the output circuit; at the moment when the primary switching tube is conducted, the impedances of the loop of the capacitor C1 and the diode D1 are smaller than that of the output filter inductor L, a low-impedance current leakage path is provided, the voltage stress of the freewheeling diode D4 can be greatly reduced, and the absorption loss is greatly reduced.
2. The output lossless snubber circuit for a forward switching power supply according to claim 1,
the transformer T has a magnetic core, a primary winding and a secondary winding.
3. The output lossless snubber circuit for a forward switching power supply according to claim 1,
the anode of the rectifier diode D3 is connected with the positive terminal of the secondary winding of the transformer T, and the freewheel diode D4 is connected with the negative terminal of the secondary winding of the transformer T.
4. The output lossless snubber circuit for a forward switching power supply according to claim 1,
the output circuit includes: a filter capacitor CE and a resistor RL;
the No. 1 pin of the output filter inductor L is simultaneously connected with the cathode of the diode D1, the anode of the filter capacitor CE and the anode of the resistor RL;
and the negative electrode of the filter capacitor CE is connected with the negative electrode of the resistor RL.
5. A forward switching power supply comprising an output lossless snubber circuit for a forward switching power supply according to any one of claims 1 to 4.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202221305330.8U CN217445258U (en) | 2022-05-27 | 2022-05-27 | Forward switching power supply and output lossless absorption circuit thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202221305330.8U CN217445258U (en) | 2022-05-27 | 2022-05-27 | Forward switching power supply and output lossless absorption circuit thereof |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN217445258U true CN217445258U (en) | 2022-09-16 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202221305330.8U Active CN217445258U (en) | 2022-05-27 | 2022-05-27 | Forward switching power supply and output lossless absorption circuit thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN217445258U (en) |
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2022
- 2022-05-27 CN CN202221305330.8U patent/CN217445258U/en active Active
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