CN113824328A - Flyback converter - Google Patents
Flyback converter Download PDFInfo
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- CN113824328A CN113824328A CN202110944937.4A CN202110944937A CN113824328A CN 113824328 A CN113824328 A CN 113824328A CN 202110944937 A CN202110944937 A CN 202110944937A CN 113824328 A CN113824328 A CN 113824328A
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- main power
- tube
- flyback converter
- power switch
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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
- H02M3/3353—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 at least two simultaneously operating switches on the input side, e.g. "double forward" or "double (switched) flyback" converter
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
- H02H7/10—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for converters; for rectifiers
- H02H7/12—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for converters; for rectifiers for static converters or rectifiers
- H02H7/1213—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for converters; for rectifiers for static converters or rectifiers for DC-DC converters
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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
- H02M1/00—Details of apparatus for conversion
- H02M1/32—Means for protecting converters other than automatic disconnection
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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)
- Dc-Dc Converters (AREA)
Abstract
The invention discloses a flyback converter, which is characterized in that on the basis of the existing back edge non-complementary flyback active clamp circuit, a controllable switch tube S3 is added in a secondary side energy transfer loop of the flyback converter and is used for controlling the switch tube S3 to be turned off for a period of time when a main power switch tube S1 is turned off and a clamp switch tube S2 is not turned on, so that the secondary side energy transfer loop is cut off, a primary side excitation inductor of a transformer T1 participates in a resonance process, the charging voltage platform value of a clamp capacitor C2 is improved, the clamp capacitor C2 can store more energy, the primary side leakage inductor storage energy is ensured to be large enough, the leakage inductor current can resonate the junction capacitor voltage of the main power switch tube S1 to be zero when the clamp switch tube S2 is turned off, and the zero voltage turning-on of the main power switch tube S1 is realized. The invention can realize the lossless absorption of leakage inductance energy, simplifies the control mode of zero voltage switch-on of the main power switch tube S1, and ensures that the main power switch tube S1 can realize the zero voltage switch-on no matter in a continuous conduction mode or an intermittent conduction mode.
Description
Technical Field
The invention relates to the field of switching power supplies, in particular to the field of flyback converters.
Background
In order to realize lossless absorption of leakage inductance energy at the primary side of the flyback converter and zero voltage switching-on of a main power switch tube, an active clamp circuit is usually introduced, the flyback converter of the existing active clamp circuit at the primary side is shown in fig. 1, wherein a main power switch tube S1, a main power transformer T1, an output rectifier diode D1 and an output filter capacitor C1 form the flyback converter, the clamp switch tube S2 and the clamp capacitor C2 are added active clamp circuits, a resistor Ro is a load, and the clamp switch tube is connected in parallel between the positive power output and the negative power output of the flyback converter.
The specific connection relationship of the circuit of fig. 1 is as follows: one end of a primary winding of a main power transformer T1 is connected with a power input positive pole, the other end of the primary winding of the main power transformer T1 is connected with a drain electrode of a main power switch tube S1, and a source electrode of the main power switch tube S1 is grounded; one end of a secondary winding of the main power transformer T1 is connected with the anode of an output rectifier diode D1, the cathode of the output rectifier diode D1 is simultaneously connected with one end of an output filter capacitor C1 and the positive power output, and the other end of the secondary winding of the main power transformer T1 is simultaneously connected with the other end of an output filter capacitor C1 and the negative power output; one end of the primary winding of the main power transformer T1 and the other end of the negative winding of the main power transformer T1 are homonymous ends; one end of a clamping capacitor C2 is connected with one end of the primary winding of the main power transformer T1, the other end of the clamping capacitor C2 is connected with the drain electrode of a clamping switch tube S2, and the source electrode of the clamping switch tube S2 is connected with the other end of the primary winding of the main power transformer T1.
Aiming at the lossless absorption of the primary side leakage inductance energy, the conventional active clamping circuit can be realized by controlling the on and off of a clamping switch tube S2. For the implementation of zero voltage switching of the main power switch tube S1, a back porch non-complementary control logic may be adopted, and the waveform diagram of the method is shown in fig. 2 and divided into the following stages:
at the time of t0-t1, the main power switch tube S1 is switched on, the transformer is excited, the clamping switch tube S2 and the main power switch tube S1 are in an off state in the period of time, and the transformer does not transfer energy to the secondary side;
at the time t1-t2, the main power switch tube S1 is turned off, the clamp switch tube S2 is not turned on, the primary side excitation inductor and the primary side leakage inductor charge the clamp capacitor C2, when the voltage at the two ends of the clamp capacitor C2 is larger than a certain value, the excitation current transfers energy to the secondary side, the clamp capacitor C2 cannot be charged continuously,
at the time t2-t3, the clamp switch tube S2 is turned on, and the energy of the clamp capacitor C2 is transferred to the primary side leakage inductance and the load Ro, which has the problem that the energy for the leakage inductance during discharging cannot meet the ZVS requirement because the energy for charging the clamp capacitor C2 is insufficient.
At the time of t3-t4, the clamping switch tube S2 is turned off, the main power switch tube S1 is not turned on, and the leakage inductance current discharges the drain-source parasitic capacitor of the main power switch tube S1, which has the problem that, because the leakage inductance energy is insufficient, the voltage at the two ends of the excitation inductor is clamped by the secondary side output voltage in the continuous mode and cannot participate in resonance, so that the energy of the drain-source parasitic capacitor of the main power switch tube S1 cannot be completely released;
at time t4-t5, ZVS cannot be achieved until the main power switch S1 is turned on, based on the above-mentioned problem.
The above-mentioned prior art trailing edge non-complementary control logic has two requirements:
1. the dead time before the clamp switch S2 turns off to the main power switch S1 turns on is required to be sufficiently small. If the main power switch S1 is turned on in time after the clamp switch S2 turns off, the leakage current will again reverse, thereby losing the soft switching characteristics. In general, the dead time TdThe selection is as follows:
wherein L iskIs the primary side leakage inductance of the transformer, Cds_s1The parasitic capacitance of the drain and the source of the main power switch tube S1, Cds_s1The parasitic capacitance of the drain and the source of the switch tube S1 is clamped.
Normally, the parasitic capacitance of the drain and the source of the switching tube is in nF level, the leakage inductance of the transformer is also in nH level, and therefore the dead time TdBelongs to ns level, and has larger control difficulty.
2. Requiring transformer primary side leakage inductance LkThe energy is sufficiently large. The reverse energy stored by the leakage inductance must be larger than the energy stored by the output capacitor of the main power switch tube S1, that is:
wherein ILKIs equivalent leakage inductance of primary side, Vds_s1Is the drain-source parasitic capacitance of the main power switch tube S1.
The minimum value of the leakage inductance is derived from equation (2):
for the above two points, the active clamp flyback circuit using the back-porch non-complementary control logic is divided into CCM and DCM modes for discussion:
(1) discontinuous conduction mode (DCM mode): generally, V is generated in a high-voltage light-load mode in formula (3)ds_s1Is large and ILkSmaller, required leakage inductance LkThe value is large, but in the DCM mode, the primary side excitation inductance participates in the resonance process of the leakage inductance and the output capacitance of the main power switch tube S1, so the leakage inductance Lk’＝LkThe leakage inductance can be assisted by the primary side inductance value and the excitation inductance to complete zero voltage switching-on of the main power switching tube, and the dead time can be relatively increased due to the participation of the primary side excitation inductance.
(2) Continuous conduction mode (CCM mode): since the primary side excitation inductor is clamped by the output side and cannot participate in the resonance process of leakage inductance and the output capacitor of the main power switch tube S1, the formula (1) and the formula (3) need to be simultaneously satisfied, namely, the dead time from the turning-off of the clamping switch tube S2 to the turning-on of the main power switch tube S1 is required to be small enough, and meanwhile, the primary side leakage inductance L of the transformer needs to be ensuredkIs sufficiently large.
In conclusion, in the CCM mode, it is difficult or even impossible to achieve zero voltage turn-on of the main power switch tube S1 by using the conventional flyback converter and the back-edge non-complementary control logic.
The above information disclosed in the background section is only for enhancement of understanding of the background of the application and therefore it may contain relevant technical information beyond the knowledge of a person of ordinary skill in the art.
Disclosure of Invention
In view of this, the technical problem to be solved by the present invention is to provide a flyback converter, that is, based on the original flyback converter, a controllable switch tube capable of controlling the on/off of the secondary side is introduced, so as to implement ZVS of the main power switch tube in any state.
In order to solve the technical problems, the technical scheme of the invention is as follows:
a flyback converter comprises a primary side loop, a transformer T1 and a secondary side energy transfer loop, wherein the primary side loop at least comprises a primary side winding of the transformer T1, a main power switch tube S1 and an active clamping circuit; the active clamping circuit at least comprises an active clamping switch tube S2 and a clamping capacitor C2; the main power switch tube S1 and the active clamping switch tube S2 are controlled by adopting a back-porch non-complementary control logic, and the main power switch tube S1 and the active clamping switch tube S2 are characterized in that:
a controllable switch tube S3 is added in the secondary side energy transfer loop of the flyback converter, and is used for controlling the controllable switch tube S3 to turn off for a period of time when the main power switch tube S1 is turned off and the clamp switch tube S2 is not turned on, so as to cut off the secondary side energy transfer loop.
Preferably, the connection relationship of the primary side loop is that one end of the primary side winding of the main power transformer T1 is connected to the positive input terminal of the power supply, the other end of the primary side winding of the main power transformer T1 is connected to the drain of the main power switch tube S1, and the source of the main power switch tube S1 is grounded; one end of the clamping capacitor C2 is connected to one end of the primary winding of the main power transformer T1, the other end of the clamping capacitor C2 is connected to the drain of the clamping switch tube S2, and the source of the clamping switch tube S2 is connected to the other end of the primary winding of the main power transformer T1.
Preferably, the connection relationship of the primary side loop is that one end of the primary side winding is connected with a power input positive electrode, the other end of the primary side winding is connected with the drain electrode of the main power switch tube S1, and the source electrode of the main power switch tube S1 is grounded; one end of the clamping capacitor C2 is connected to the drain of the main power switch tube S1, the other end of the clamping capacitor C2 is connected to the drain of the clamping switch tube S2, and the source of the clamping switch tube S2 is connected to the source of the main power switch tube S1.
Preferably, the controllable switch tube S3 is a MOS tube, an IGBT, a thyristor or a relay.
Preferably, the secondary side energy transfer loop at least comprises a secondary side winding of the transformer T1, a rectifying switch tube and the controllable switch tube S3; one end of the secondary winding is connected with one end of the rectification switching tube, the other end of the rectification switching tube is connected with one end of the controllable switching tube S3, the other end of the controllable switching tube S3 is connected with the positive power output, and the negative power output is connected with the other end of the secondary winding.
Preferably, the rectifying switch tube is a diode D1, the anode of the diode D1 is one end of the rectifying switch tube, and the cathode of the diode D1 is the other end of the rectifying switch tube; or the rectifying switch tube is an MOS tube S4, the source electrode of the MOS tube S4 is one end of the rectifying switch tube, and the drain electrode of the MOS tube S4 is the other end of the rectifying switch tube.
Preferably, the secondary side energy transfer loop at least comprises a secondary side winding of the transformer T1, a rectifying switch tube and the controllable switch tube S3; one end of the secondary winding is connected with the positive power output, the negative power output is connected with one end of the rectification switching tube, the other end of the rectification switching tube is connected with one end of the controllable switching tube S3, and the other end of the controllable switching tube S3 is connected with the other end of the secondary winding.
Preferably, the rectifying switch tube is a diode D1, the anode of the diode D1 is one end of the rectifying switch tube, and the cathode of the diode D1 is the other end of the rectifying switch tube; or the rectifying switch tube is an MOS tube S4, the source electrode of the MOS tube S4 is one end of the rectifying switch tube, and the drain electrode of the MOS tube S4 is the other end of the rectifying switch tube.
The working principle of the present invention will be analyzed in detail by combining with specific embodiments, which are not described herein, and the beneficial effects of the present invention compared with the prior art are as follows:
when the primary side main power switch tube is turned off and the clamping switch tube is not conducted, the controllable switch tube introduced by the secondary side is controlled to be turned off for a period of time, and the energy transfer loop of the secondary side is cut off, so that the primary side excitation inductor of the main power transformer participates in the resonance process, the charging voltage platform value of the clamping capacitor is increased, the primary side leakage inductor storage energy is ensured to be large enough, the control mode for realizing the primary side main power switch tube ZVS can be simplified, and the primary side main power switch tube can realize ZVS in any state.
Drawings
Fig. 1 is a schematic diagram of a flyback converter with an active clamp circuit in the prior art;
fig. 2 is a control logic diagram of a flyback converter with a primary side having a source clamp circuit in the prior art;
fig. 3 is a schematic diagram of a flyback converter of a first embodiment of the present invention;
fig. 4 is a control logic diagram of the flyback converter of the present invention for the first embodiment;
fig. 5 is a schematic diagram of a flyback converter of a second embodiment of the present invention;
fig. 6 is a schematic diagram of a flyback converter of a third embodiment of the present invention;
fig. 7 is a schematic diagram of a flyback converter of a fourth embodiment of the present invention;
fig. 8 is a schematic diagram of a flyback converter according to a fifth embodiment of the present invention.
Detailed Description
The invention of the application is based on the existing back edge non-complementary flyback active clamp circuit, a controllable switch tube S3 is added in a secondary side energy transfer loop of a flyback converter, and is used for controlling the switch tube S3 to be turned off for a period of time when a main power switch tube S1 is turned off and a clamp switch tube S2 is not turned on, so that the secondary side energy transfer loop is cut off, a primary side excitation inductor of a transformer T1 participates in a resonance process, a charging voltage platform value of a clamp capacitor C2 is improved, the clamp capacitor C2 can store more energy, the primary side leakage inductor storage energy is ensured to be large enough, when the clamp switch tube S2 is turned off, leakage current can resonate the junction capacitor voltage of the main power switch tube S1 to zero, and zero voltage switching on of the main power switch tube S1 is realized.
The invention can realize the lossless absorption of leakage inductance energy, simplifies the control mode of zero voltage switch-on of the main power switch tube S1, and ensures that the main power switch tube S1 can realize the zero voltage switch-on no matter in a continuous conduction mode or an intermittent conduction mode.
In order that those skilled in the art will better understand the present invention, the present invention will be further described below in conjunction with specific implementation circuits.
First embodiment
Fig. 3 shows a schematic diagram of a first embodiment of the flyback converter of the present invention, which is different from fig. 1 in that a MOS transistor S3 is added in the flyback converter secondary side energy transfer loop, specifically, the drain of the MOS transistor S3 is connected to the cathode of the output rectifier diode D1, and the source of the MOS transistor S3 is simultaneously connected to one end of the output filter capacitor C1 and the positive power supply output.
Fig. 4 is a control logic diagram of the flyback converter according to the first embodiment of the present invention, and the operation principle of the present embodiment is analyzed with reference to fig. 4 as follows:
wherein G isS1Is the driving waveform G of the main power switch tube S1S2Drive waveform G for clamping switch tube S2S3The driving waveform of the MOS tube S3 added in the secondary side energy transfer loop;
at the time 0-t1, the main power switch tube S1 is switched on and starts to excite the transformer, the switch tubes S2 and S3 are in an off state during the period, and the transformer does not transfer energy to the secondary side;
at the time of t1-t2, the main power switch tube S1 is turned off, the clamping switch tube S2 is not turned on, the secondary controllable switch tube S3 is turned off, and the primary side excitation inductor, the primary side leakage inductor and the clamping capacitor C2 resonate to charge the clamping capacitor C2 together by the leakage inductor and the primary side excitation inductor, so that the charging voltage platform value of the clamping capacitor C2 is increased;
at the time of t2-t3, the secondary side switching tube S3 is in a conducting state, the switching tubes S1 and S2 are in a switching-off state, the transformer is demagnetized in the period, and the transformer transmits energy to the secondary side as common flyback transformers;
at the time of t3-t4, the clamp switch tube S2 is turned on, the energy of the clamp capacitor C2 is transferred to the primary side leakage inductance and the load Ro, and the energy of the leakage inductance is increased because the charging voltage platform value of the clamp capacitor C2 is increased and the energy required by the load Ro is fixed;
at the time of t4-t5, the clamping switch tube S2 is turned off, the main power switch tube S1 is not turned on, if the circuit works in a DCM mode, a primary side excitation inductor, a leakage inductor and the output capacitor (namely, a drain-source electrode parasitic capacitor) of the main power switch tube S1 are subjected to common resonance to realize ZVS of the main power switch tube S1, which is the same as that of a conventional flyback converter, and the drain-source electrode parasitic capacitor of the main power switch tube S1 is easy to resonate to zero due to the addition of the excitation inductor in the resonance process; if the circuit works in a CCM mode, the leakage inductance current discharges the parasitic capacitance of the drain-source electrode of the main power switch tube S1, and the leakage inductance energy is large enough, so that the voltage across the main power switch tube S1 is enough to be zero and then reverse, and the ZVS of the main power switch tube S1 is ensured.
At this point, a duty cycle ends and the process is repeated.
Second embodiment
The second embodiment is shown in fig. 5, and the differences from the first embodiment are: the MOS tube S3 adopts a low-end starting mode, the connection mode is different, specifically, the drain electrode of the MOS tube S3 is simultaneously connected with the other end of the output filter capacitor C1 and the power output negative electrode, and the source electrode of the MOS tube S3 is connected with the other end of the secondary winding of the main power transformer T1.
The working principle of this embodiment is the same as that of the first embodiment, and will not be described herein.
Third embodiment
As an equivalent alternative to the flyback converter shown in fig. 1, the anode of the output rectifying diode D1 may be connected to the other end of the output filter capacitor C1 and the negative power output, the cathode of the output rectifying diode D1 is connected to the other end of the secondary winding of the main power transformer T1, the third embodiment is an improvement based on the equivalent alternative circuit, specifically, a MOS transistor S3 is added to the secondary energy transfer loop, the drain of the MOS transistor S3 is connected to the cathode of the output rectifying diode D1, and the source of the MOS transistor S3 is connected to the other end of the secondary winding of the main power transformer T1, and the specific circuit is as shown in fig. 6.
The working principle of this embodiment is the same as that of the first embodiment, and will not be described herein.
Fourth embodiment
The fourth embodiment is shown in fig. 7, and the differences from the first embodiment are: the fourth embodiment replaces the output rectifier diode D1 with a secondary side synchronous rectifier S4, and the efficiency of the flyback converter can be improved by using synchronous rectification for the secondary side.
The working principle of this embodiment is the same as that of the first embodiment, and will not be described herein.
Fifth embodiment
As another equivalent alternative of the flyback converter shown in fig. 1, the active clamp circuit may be connected in parallel to both ends of the drain and source of the main power switch tube S1, specifically, one end of the clamp capacitor C2 is connected to the drain of the main power switch tube S1, the other end of the clamp capacitor C2 is connected to the drain of the clamp switch tube S2, the source of the clamp switch tube S2 is connected to the source of the main power switch tube S1, the fifth embodiment is an improvement based on the equivalent alternative, specifically, the secondary side energy transfer circuit is added with a MOS tube S3, the drain of the MOS tube S3 is connected to the cathode of the output rectifier diode D1, and the source of the MOS tube S3 is connected to both end of the output filter capacitor C1 and the power output node, as shown in fig. 8.
The working principle of this embodiment is the same as that of the first embodiment, and will not be described herein.
In the above preferred embodiments of the present invention, it should be noted that the above preferred embodiments should not be considered as limitations of the present invention, and it will be apparent to those skilled in the art that several modifications and decorations can be made without departing from the spirit and scope of the present invention, for example, a modification of the same name terminal of the transformer T1, a modification of the switching tube added in the secondary side energy transfer loop of the flyback converter to other devices that can achieve the same function, such as a MOS tube, an IGBT, a thyristor, a relay, etc., a modification of circuits other than the fourth embodiment to a synchronous rectification manner, and a modification of all circuits that achieve this function and these modifications and decorations should also be considered as protection scope of the present invention, and the protection scope of the present invention should be subject to the scope defined by the claims.
Claims (8)
1. A flyback converter comprises a primary side loop, a transformer T1 and a secondary side energy transfer loop, wherein the primary side loop at least comprises a primary side winding of the transformer T1, a main power switch tube S1 and an active clamping circuit; the active clamping circuit at least comprises an active clamping switch tube S2 and a clamping capacitor C2; the main power switch tube S1 and the active clamping switch tube S2 are controlled by adopting a back-porch non-complementary control logic, and the main power switch tube S1 and the active clamping switch tube S2 are characterized in that:
a controllable switch tube S3 is added in the secondary side energy transfer loop of the flyback converter, and is used for controlling the controllable switch tube S3 to turn off for a period of time when the main power switch tube S1 is turned off and the clamp switch tube S2 is not turned on, so as to cut off the secondary side energy transfer loop.
2. The flyback converter of claim 1, wherein: the connection relationship of the primary side loop is that one end of a primary side winding of the main power transformer T1 is connected with a power input positive electrode, the other end of the primary side winding of the main power transformer T1 is connected with the drain electrode of the main power switch tube S1, and the source electrode of the main power switch tube S1 is grounded; one end of the clamping capacitor C2 is connected to one end of the primary winding of the main power transformer T1, the other end of the clamping capacitor C2 is connected to the drain of the clamping switch tube S2, and the source of the clamping switch tube S2 is connected to the other end of the primary winding of the main power transformer T1.
3. The flyback converter of claim 1, wherein: the connection relationship of the primary side loop is that one end of the primary side winding is connected with a power input positive electrode, the other end of the primary side winding is connected with the drain electrode of the main power switch tube S1, and the source electrode of the main power switch tube S1 is grounded; one end of the clamping capacitor C2 is connected to the drain of the main power switch tube S1, the other end of the clamping capacitor C2 is connected to the drain of the clamping switch tube S2, and the source of the clamping switch tube S2 is connected to the source of the main power switch tube S1.
4. The flyback converter of claim 1, wherein: the controllable switch tube S3 is MOS tube, IGBT, silicon controlled rectifier or relay.
5. A flyback converter according to any of claims 1 to 4, characterized in that: the secondary side energy transfer loop at least comprises a secondary side winding of the transformer T1, a rectifying switch tube and the controllable switch tube S3; one end of the secondary winding is connected with one end of the rectification switching tube, the other end of the rectification switching tube is connected with one end of the controllable switching tube S3, the other end of the controllable switching tube S3 is connected with the positive power output, and the negative power output is connected with the other end of the secondary winding.
6. The flyback converter of claim 5, wherein: the rectifying switch tube is a diode D1, the anode of the diode D1 is one end of the rectifying switch tube, and the cathode of the diode D1 is the other end of the rectifying switch tube; or the rectifying switch tube is an MOS tube S4, the source electrode of the MOS tube S4 is one end of the rectifying switch tube, and the drain electrode of the MOS tube S4 is the other end of the rectifying switch tube.
7. A flyback converter according to any of claims 1 to 4, characterized in that: the secondary side energy transfer loop at least comprises a secondary side winding of the transformer T1, a rectifying switch tube and the controllable switch tube S3; one end of the secondary winding is connected with the positive power output, the negative power output is connected with one end of the rectification switching tube, the other end of the rectification switching tube is connected with one end of the controllable switching tube S3, and the other end of the controllable switching tube S3 is connected with the other end of the secondary winding.
8. The flyback converter of claim 7, wherein: the rectifying switch tube is a diode D1, the anode of the diode D1 is one end of the rectifying switch tube, and the cathode of the diode D1 is the other end of the rectifying switch tube; or the rectifying switch tube is an MOS tube S4, the source electrode of the MOS tube S4 is one end of the rectifying switch tube, and the drain electrode of the MOS tube S4 is the other end of the rectifying switch tube.
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| CN202110944937.4A CN113824328B (en) | 2021-08-17 | 2021-08-17 | Flyback converter |
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| CN202110944937.4A CN113824328B (en) | 2021-08-17 | 2021-08-17 | Flyback converter |
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Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN201118451Y (en) * | 2007-11-29 | 2008-09-17 | 上海辰蕊微电子科技有限公司 | Lossless Snubber Circuit for Flyback Switching Power Supply |
| EP3255769A1 (en) * | 2016-06-06 | 2017-12-13 | RK Rose + Krieger GmbH Verbindungs- und Positioniersysteme | Switching power supply |
| CN110601540A (en) * | 2019-08-21 | 2019-12-20 | 杰华特微电子（杭州）有限公司 | Active clamp flyback circuit and control method thereof |
| CN111478589A (en) * | 2020-04-10 | 2020-07-31 | 杭州士兰微电子股份有限公司 | Flyback converter and control circuit and control method thereof |
| CN111555626A (en) * | 2020-05-08 | 2020-08-18 | 东南大学 | A control method and system for an active clamp flyback converter |
| CN112510976A (en) * | 2020-12-22 | 2021-03-16 | 广州金升阳科技有限公司 | Active clamp flyback converter, controller and control method thereof |
-
2021
- 2021-08-17 CN CN202110944937.4A patent/CN113824328B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN201118451Y (en) * | 2007-11-29 | 2008-09-17 | 上海辰蕊微电子科技有限公司 | Lossless Snubber Circuit for Flyback Switching Power Supply |
| EP3255769A1 (en) * | 2016-06-06 | 2017-12-13 | RK Rose + Krieger GmbH Verbindungs- und Positioniersysteme | Switching power supply |
| CN110601540A (en) * | 2019-08-21 | 2019-12-20 | 杰华特微电子（杭州）有限公司 | Active clamp flyback circuit and control method thereof |
| CN111478589A (en) * | 2020-04-10 | 2020-07-31 | 杭州士兰微电子股份有限公司 | Flyback converter and control circuit and control method thereof |
| CN111555626A (en) * | 2020-05-08 | 2020-08-18 | 东南大学 | A control method and system for an active clamp flyback converter |
| CN112510976A (en) * | 2020-12-22 | 2021-03-16 | 广州金升阳科技有限公司 | Active clamp flyback converter, controller and control method thereof |
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