CN107317482B - Self-driven synchronous rectification circuit and switching power supply thereof - Google Patents
Self-driven synchronous rectification circuit and switching power supply thereof Download PDFInfo
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- CN107317482B CN107317482B CN201710756417.4A CN201710756417A CN107317482B CN 107317482 B CN107317482 B CN 107317482B CN 201710756417 A CN201710756417 A CN 201710756417A CN 107317482 B CN107317482 B CN 107317482B
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- 230000001360 synchronised effect Effects 0.000 title claims abstract description 35
- 238000004804 winding Methods 0.000 claims description 14
- 238000006243 chemical reaction Methods 0.000 abstract description 9
- 230000015556 catabolic process Effects 0.000 abstract description 4
- 239000003990 capacitor Substances 0.000 description 10
- 230000005669 field effect Effects 0.000 description 4
- 238000000034 method Methods 0.000 description 2
- 230000004075 alteration Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
Classifications
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M3/00—Conversion of dc power input into dc power output
- H02M3/22—Conversion of dc power input into dc power output with intermediate conversion into ac
- H02M3/24—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters
- H02M3/28—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac
- H02M3/325—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal
- H02M3/335—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only
- H02M3/33569—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only having several active switching elements
- H02M3/33576—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only having several active switching elements having at least one active switching element at the secondary side of an isolation transformer
- H02M3/33592—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only having several active switching elements having at least one active switching element at the secondary side of an isolation transformer having a synchronous rectifier circuit or a synchronous freewheeling circuit at the secondary side of an isolation transformer
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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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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Rectifiers (AREA)
- Dc-Dc Converters (AREA)
Abstract
The invention discloses a self-driven synchronous rectification circuit which comprises an MOS tube and a transformer for generating synchronous driving signals to control the MOS tube, wherein the self-driven synchronous rectification circuit also comprises a current limiting circuit, a first voltage reducing circuit and a first voltage dividing circuit, and the output end of the transformer is connected with the MOS tube after passing through the current limiting circuit, the first voltage reducing circuit and the first voltage dividing circuit which are sequentially connected in series. The invention also discloses a switching power supply with the self-driven synchronous rectification circuit. The invention can not only improve the conversion efficiency of the power supply, but also avoid breakdown of the MOS tube.
Description
Technical Field
The invention relates to the technical field of switching power supplies, in particular to a self-driven synchronous rectification circuit and a switching power supply thereof.
Background
The switching power supply is used as a high-frequency electric energy conversion device, and an electronic switching device (such as a transistor, a field effect transistor, a thyristor and the like) is utilized, and the electronic switching device is continuously turned on and off through a control circuit, so that the electronic switching device carries out pulse modulation on input voltage, thereby realizing DC/AC and DC/DC voltage conversion, and the output voltage can be regulated automatically.
In order to reduce the rectifying loss of the switching power supply adopting the rectifying diode, a part of the existing switching power supplies currently adopt a field effect transistor with extremely low on-state resistance, namely an MOS tube to replace the rectifying diode so as to realize the self-driven synchronous rectification of the switching power supply. The MOS tube belongs to a voltage control type device, so that the current limiting resistor is connected with the transformer winding in the switching power supply at the current stage to directly drive the MOS tube, and the MOS tube is conducted to achieve the aim of synchronous rectification. However, the synchronous rectification circuit not only reduces the conversion efficiency of the switching power supply, but also easily causes the field effect transistor to break down.
Disclosure of Invention
In order to overcome the defects in the prior art, the invention aims to provide a self-driven synchronous rectification circuit which can improve the conversion efficiency of a power supply and avoid the breakdown of a field effect transistor.
The aim of the invention is achieved by the following technical scheme:
the self-driven synchronous rectification circuit comprises a MOS tube, a transformer for generating synchronous driving signals to control the MOS tube, a current limiting circuit, a first voltage reducing circuit and a first voltage dividing circuit, wherein the output end of the transformer is connected with the MOS tube after passing through the current limiting circuit, the first voltage reducing circuit and the first voltage dividing circuit which are sequentially connected in series.
Preferably, one end of the secondary winding of the transformer is connected with the input end of the current limiting circuit, the other end of the secondary winding of the transformer is grounded, a center tap of the secondary winding of the transformer is respectively connected with a source electrode of the MOS tube and an output end of the first voltage dividing circuit, a grid electrode of the MOS tube is connected between the first voltage reducing circuit and the first voltage dividing circuit, and a drain electrode of the MOS tube is connected with a load.
Preferably, the self-driven synchronous rectification circuit further comprises a second voltage reduction circuit connected in series between the output end of the first voltage reduction circuit and the grid electrode of the MOS tube.
Preferably, the self-driven synchronous rectification circuit further comprises a second voltage division circuit, one end of the second voltage division circuit is connected with the source electrode of the MOS tube, and the other end of the second voltage division circuit is connected between the second voltage division circuit and the grid electrode of the MOS tube.
Preferably, the current limiting circuit comprises a first current limiting resistor and a second current limiting resistor which are connected in parallel.
Preferably, the first voltage reducing circuit includes a first voltage reducing capacitor and a second voltage reducing capacitor connected in parallel.
Preferably, the first voltage dividing circuit includes a first voltage dividing resistor.
Preferably, the second step-down circuit includes a third step-down capacitor.
Preferably, the second voltage dividing circuit includes a second voltage dividing resistor.
In order to solve the same technical problems, the invention also provides a switching power supply which comprises the self-driven synchronous rectification circuit.
Compared with the prior art, the invention has the following beneficial effects:
according to the invention, the current limiting circuit, the first voltage reducing circuit and the first voltage dividing circuit which are sequentially connected are arranged between the output end of the transformer and the MOS tube, so that when the output of the secondary winding of the transformer is conducted, the secondary winding of the transformer simultaneously outputs synchronous driving waveforms to the MOS tube, and the MOS tube is driven to achieve the purpose of outputting synchronous rectification. Meanwhile, in the process, the driving waveform output by the transformer is ensured to be subjected to current limiting through the current limiting circuit, then is subjected to voltage reduction through the first voltage reducing circuit and then is subjected to voltage division through the first voltage dividing circuit, so that the voltage for driving the MOS tube is stable and is within a limited range, the conversion efficiency of a power supply is improved, breakdown of the MOS tube is avoided, and the MOS tube is prevented from being damaged.
Drawings
Fig. 1 is a schematic circuit diagram of a self-driven synchronous rectification circuit according to an embodiment of the present invention.
Detailed Description
The invention will now be described in further detail with reference to the drawings and to specific examples.
As shown in fig. 1, a self-driven synchronous rectification circuit of the preferred embodiment of the present invention includes a MOS transistor Q1, and a transformer T1 for generating a synchronous driving signal to control the MOS transistor Q1, where the self-driven synchronous rectification circuit further includes a current limiting circuit 1, a first voltage reducing circuit 2, and a first voltage dividing circuit 3, and an output end of the transformer T1 is connected with the MOS transistor Q1 after passing through the current limiting circuit 1, the first voltage reducing circuit 2, and the first voltage dividing circuit 3 which are sequentially connected in series.
Specifically, one end of the secondary winding of the transformer T1 is connected with the input end of the current limiting circuit 1, the other end of the secondary winding of the transformer T1 is grounded, a center tap of the secondary winding of the transformer T1 is respectively connected with a source electrode of the MOS transistor Q1 and an output end of the first voltage dividing circuit 3, a gate electrode of the MOS transistor Q1 is connected between the first voltage reducing circuit 2 and the first voltage dividing circuit 3, and a drain electrode of the MOS transistor Q1 is connected with a load.
The self-driven synchronous rectification circuit adopts the transformer T1Q 1 to drive the MOS tube Q1 to work, and when the output of the secondary winding of the transformer T1 is conducted, the secondary winding of the transformer T1 simultaneously outputs synchronous driving waveforms to the MOS tube Q1 so as to drive the MOS tube Q1 to achieve the aim of outputting synchronous rectification. In this process, the driving waveform output by the transformer T1 is reduced in voltage by the first voltage reducing circuit 2 after being limited by the current limiting circuit 1, and then is divided in voltage by the first voltage dividing circuit 3, so that the voltage for driving the MOS transistor Q1 is stable and within a limited range, thereby improving the conversion efficiency of the power supply, avoiding breakdown of the MOS transistor Q1, and protecting it from damage.
In order to further improve the conversion efficiency of the self-driven synchronous rectification circuit and the protection effect on the MOS transistor Q1, the self-driven synchronous rectification circuit may further include a second step-down circuit 4 connected in series between the output end of the first step-down circuit 2 and the gate of the MOS transistor Q1. Preferably, the self-driven synchronous rectification circuit may further include a second voltage division circuit 5, one end of the second voltage division circuit 5 is connected to the source electrode of the MOS transistor Q1, and the other end of the second voltage division circuit is connected between the second voltage reduction circuit 4 and the gate electrode of the MOS transistor Q1. Of course, the number of the voltage dividing circuits and the voltage reducing circuits may be increased as needed.
For simplicity of the circuit, the current limiting circuit 1 may include a first current limiting resistor R1 and a second current limiting resistor R2 connected in parallel, for example. The first buck circuit 2 may include a first buck capacitor C1 and a second buck capacitor C2 connected in parallel. The first voltage dividing circuit 3 may include a first voltage dividing resistor R3. The second step-down circuit 4 may include a third step-down capacitor C3. The second voltage dividing circuit 5 may include a second voltage dividing resistor R4.
The embodiment of the invention also provides a switching power supply with the self-driven synchronous rectification circuit, so as to improve the conversion efficiency of the power supply and protect the MOS tube Q1. For example, after synchronous rectification is implemented, the output rectified wave may be filtered by the first filter capacitor C4, the first filter inductor L1, the second filter capacitor C5, the third filter capacitor C6, and the fourth filter capacitor C7.
The embodiments of the present invention are not limited thereto, and the present invention may be modified, replaced or altered in various other ways by using the general knowledge and conventional means in the art according to the above-mentioned aspects of the present invention without departing from the basic technical idea of the present invention, and all the modifications and alterations fall within the scope of the present invention.
Claims (2)
1. The self-driven synchronous rectification circuit comprises an MOS tube and a transformer for generating synchronous driving signals to control the MOS tube, and is characterized by further comprising a current limiting circuit, a first voltage reducing circuit and a first voltage dividing circuit, wherein the output end of the transformer is connected with the MOS tube after passing through the current limiting circuit, the first voltage reducing circuit and the first voltage dividing circuit which are sequentially connected in series;
one end of a secondary winding of the transformer is connected with the input end of the current limiting circuit, the other end of the secondary winding of the transformer is grounded, a center tap of the secondary winding of the transformer is respectively connected with a source electrode of the MOS tube and an output end of the first voltage dividing circuit, a grid electrode of the MOS tube is connected between the first voltage reducing circuit and the first voltage dividing circuit, and a drain electrode of the MOS tube is connected with a load;
the self-driven synchronous rectification circuit further comprises a second voltage reduction circuit connected in series between the output end of the first voltage reduction circuit and the grid electrode of the MOS tube;
the self-driven synchronous rectification circuit further comprises a second voltage division circuit, one end of the second voltage division circuit is connected with the source electrode of the MOS tube, and the other end of the second voltage division circuit is connected between the second voltage division circuit and the grid electrode of the MOS tube.
2. A switching power supply, comprising: the self-driven synchronous rectification circuit of claim 1.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710756417.4A CN107317482B (en) | 2017-08-29 | 2017-08-29 | Self-driven synchronous rectification circuit and switching power supply thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710756417.4A CN107317482B (en) | 2017-08-29 | 2017-08-29 | Self-driven synchronous rectification circuit and switching power supply thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN107317482A CN107317482A (en) | 2017-11-03 |
| CN107317482B true CN107317482B (en) | 2024-03-12 |
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| CN201710756417.4A Active CN107317482B (en) | 2017-08-29 | 2017-08-29 | Self-driven synchronous rectification circuit and switching power supply thereof |
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Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2003033016A (en) * | 2001-07-09 | 2003-01-31 | Nec Computertechno Ltd | Switching power supply |
| JP2004274823A (en) * | 2003-03-05 | 2004-09-30 | Tdk Corp | Switching power supply |
| JP2007097377A (en) * | 2005-09-30 | 2007-04-12 | Shindengen Electric Mfg Co Ltd | Synchronous rectification driving circuit |
| TW200915707A (en) * | 2007-09-21 | 2009-04-01 | Glacialtech Inc | Forward converter with self-driven synchronous rectifier |
| CN105846700A (en) * | 2016-03-29 | 2016-08-10 | 广州视源电子科技股份有限公司 | LLC half-bridge resonant converter and secondary synchronous rectifying device thereof |
| CN206341152U (en) * | 2016-12-26 | 2017-07-18 | 常州市创联电源科技股份有限公司 | A kind of output synchronous commutation self-driving circuit of positive activation type Switching Power Supply |
| CN107017789A (en) * | 2017-05-05 | 2017-08-04 | 苏州纽克斯电源技术股份有限公司 | Rectifying output circuit and its control method |
| CN207251479U (en) * | 2017-08-29 | 2018-04-17 | 广州市爱浦电子科技有限公司 | A kind of self-powered circuit of synchronous rectification and its Switching Power Supply |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7362598B2 (en) * | 2004-12-17 | 2008-04-22 | Artesyn Technologies, Inc. | Synchronous rectifier gate drive shutdown circuit |
-
2017
- 2017-08-29 CN CN201710756417.4A patent/CN107317482B/en active Active
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2003033016A (en) * | 2001-07-09 | 2003-01-31 | Nec Computertechno Ltd | Switching power supply |
| JP2004274823A (en) * | 2003-03-05 | 2004-09-30 | Tdk Corp | Switching power supply |
| JP2007097377A (en) * | 2005-09-30 | 2007-04-12 | Shindengen Electric Mfg Co Ltd | Synchronous rectification driving circuit |
| TW200915707A (en) * | 2007-09-21 | 2009-04-01 | Glacialtech Inc | Forward converter with self-driven synchronous rectifier |
| CN105846700A (en) * | 2016-03-29 | 2016-08-10 | 广州视源电子科技股份有限公司 | LLC half-bridge resonant converter and secondary synchronous rectifying device thereof |
| CN206341152U (en) * | 2016-12-26 | 2017-07-18 | 常州市创联电源科技股份有限公司 | A kind of output synchronous commutation self-driving circuit of positive activation type Switching Power Supply |
| CN107017789A (en) * | 2017-05-05 | 2017-08-04 | 苏州纽克斯电源技术股份有限公司 | Rectifying output circuit and its control method |
| CN207251479U (en) * | 2017-08-29 | 2018-04-17 | 广州市爱浦电子科技有限公司 | A kind of self-powered circuit of synchronous rectification and its Switching Power Supply |
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| CN107317482A (en) | 2017-11-03 |
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