CN210120487U - Clamping circuit and flyback converter - Google Patents
Clamping circuit and flyback converter Download PDFInfo
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- CN210120487U CN210120487U CN201920630508.8U CN201920630508U CN210120487U CN 210120487 U CN210120487 U CN 210120487U CN 201920630508 U CN201920630508 U CN 201920630508U CN 210120487 U CN210120487 U CN 210120487U
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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
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- 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 embodiment of the utility model discloses a clamp circuit and flyback converter, flyback converter includes transformer, rectifier diode, first electric capacity, second electric capacity, resonance inductance, magnetization inductance, first resistance, power switch tube and the equivalent capacitance that power switch tube corresponds; the clamping circuit comprises a clamping switch tube and a clamping capacitor; when the power supply works and the power switch tube is switched off after being switched on, the clamping capacitor is used for absorbing the peak energy of the switching-off voltage generated by switching off the power switch tube after being switched on from the resonant inductor and feeding the peak energy of the switching-off voltage back to the power supply side. The utility model discloses the voltage spike that the sense of leakage that the clamp circuit can eliminate flyback converter arouses.
Description
Technical Field
The utility model relates to an electronic circuit technical field, concretely relates to clamp circuit and flyback converter.
Background
The flyback converter has the advantages of simple circuit topological structure, input and output electrical isolation, wide voltage rising/falling range, easiness in multi-path output, high reliability, high cost performance and the like, and is widely applied to medium and small power occasions. However, due to the influence of the leakage inductance of the transformer caused by the large voltage and current stress of the power switch, a large voltage spike is caused when the power switch tube of the flyback converter is turned off.
SUMMERY OF THE UTILITY MODEL
An embodiment of the utility model provides a clamp circuit and flyback converter can eliminate the voltage spike that the leakage inductance of flyback converter arouses.
The embodiment of the utility model provides a first aspect provides a clamp circuit, the clamp circuit is applied to flyback converter, flyback converter includes transformer, rectifier diode, first electric capacity, second electric capacity, resonance inductance, magnetization inductance, first resistance, power switch tube and the equivalent capacitance that power switch tube corresponds; the clamping circuit comprises a clamping switch tube and a clamping capacitor; wherein:
the first end of the first capacitor is connected with the first end of the clamping capacitor and the first end of the resonant inductor, the second end of the clamping capacitor is connected with the drain electrode of the clamping switch tube, the source electrode of the clamping switch tube is connected with the drain electrode of the power switch tube and the first end of the equivalent capacitor, and the source electrode of the power switch tube and the second end of the equivalent capacitor are grounded; the second end of the resonance inductor is connected with the first end of the magnetizing inductor and the first end of the primary coil of the transformer, and the second end of the magnetizing inductor is connected with the second end of the primary coil and the source electrode of the clamping switch tube; a first end of a secondary coil of the transformer is connected with an anode of the rectifier diode, a cathode of the rectifier diode is connected with a first end of the second capacitor and a first end of the first resistor, and a second end of the secondary coil of the transformer, a second end of the second capacitor and a second end of the first resistor are grounded; the first end of the first capacitor is connected with the positive end of a power supply, and the second end of the first capacitor is connected with the negative end of the power supply;
when the power supply works and the power switch tube is switched off after being switched on, the clamping capacitor is used for absorbing off-voltage peak energy generated by switching off the power switch tube after being switched on from the resonant inductor and feeding back the off-voltage peak energy to the power supply side.
Optionally, the clamping capacitor includes at least two clamping sub-capacitors, and the at least two clamping sub-capacitors are connected in series.
The embodiment of the utility model provides a second aspect provides a flyback converter, flyback converter includes transformer, rectifier diode, first electric capacity, second electric capacity, resonance inductance, magnetization inductance, first resistance, power switch tube equivalent capacitance that power switch tube corresponds the utility model discloses the first aspect clamp circuit, clamp circuit includes clamp switch tube and clamp capacitance.
The embodiment of the utility model provides an in provide a clamp circuit and flyback converter, when the power during operation of flyback converter, when the power switch tube switches on the back and shuts off, clamp capacitance among the clamp circuit is arranged in absorbing because the turn-off voltage peak energy of turn-off production after the power switch tube switches on from resonant inductor to with turn-off voltage peak energy repayment to the power side, thereby can eliminate the voltage peak that the leakage inductance that turns on the flyback converter arouses.
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 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 schematic structural diagram of a clamp circuit according to an embodiment of the present invention;
fig. 2 is a schematic waveform diagram of a flyback converter disclosed in an embodiment of the present application;
fig. 3 is a schematic structural diagram of a flyback converter disclosed in an embodiment of the present application.
Detailed Description
The technical solution of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. It is to be understood that the embodiments described are some, but not all embodiments of the invention. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative efforts shall fall within the protection scope of the present invention.
An embodiment of the utility model provides a clamp circuit and flyback converter can eliminate the voltage spike that the leakage inductance of flyback converter arouses. The following are detailed below.
Referring to fig. 1, fig. 1 is a schematic structural diagram of a clamp circuit according to an embodiment of the present invention. As shown in fig. 1, the clamping circuit 10 described in the present embodiment is applied to a flyback converter 20, and the flyback converter 20 includes a transformer T1, a rectifier diode D1, a first capacitor C1, a second capacitor C2, a resonant inductor Lr, a magnetizing inductor Lm, a first resistor R1, a power switch Q1, and an equivalent capacitor Cr corresponding to the power switch Q1; the clamping circuit 10 comprises a clamping switch tube Q2 and a clamping capacitor Cc; wherein:
the first end of the first capacitor C1 is connected with the first end of the clamping capacitor Cc and the first end of the resonance inductor Lr, the second end of the clamping capacitor Cc is connected with the drain electrode of the clamping switch tube Q2, the source electrode of the clamping switch tube Q2 is connected with the drain electrode of the power switch tube Q1 and the first end of the equivalent capacitor Cr, and the source electrode of the power switch tube Q1 and the second end of the equivalent capacitor Cr are grounded; the second end of the resonant inductor Lr is connected with the first end of the magnetizing inductor Lm and the first end of the primary coil N1 of the transformer T1, and the second end of the magnetizing inductor Lm is connected with the second end of the primary coil N1 and the source of the clamping switch tube Q2; a first end of a secondary coil N2 of the transformer T1 is connected with an anode of a rectifier diode D1, a cathode of the rectifier diode D1 is connected with a first end of a second capacitor C2 and a first end of a first resistor R1, and a second end of a secondary coil N2 of the transformer T1, a second end of the second capacitor C2 and a second end of a first resistor R1 are grounded; a first end of the first capacitor C1 is connected with the positive end of the power supply Ui, and a second end of the first capacitor C1 is connected with the negative end of the power supply Ui;
when the power supply Ui works, when the power switch tube Q1 is turned off after being turned on, the clamping capacitor Cc is used for absorbing off-voltage spike energy generated by turning off the power switch tube Q1 after being turned on from the resonant inductor Lr and feeding back the off-voltage spike energy to the side of the power supply Ui.
The flyback converter 20 may be applied to a switching power supply, and the flyback converter 20 may also be referred to as: an active clamped flyback converter. The power source Ui may be an ac grid.
The power switch Q1 and the clamp switch Q2 may be N-Metal-Oxide-Semiconductor (NMOS) field effect transistors. The power switch tube Q1 and the clamping switch tube Q2 can be switched on at a high level and switched off at a low level.
The flyback converter 20 further includes a power controller 21, a control terminal of the power controller 21 is connected to the gate of the power switch Q1, and the power controller 21 is configured to control the power switch Q1 to be turned on or off.
The power controller 21 may output a Pulse Width Modulation (PWM) signal to control the power transistor Q1 to turn on or off. As shown in fig. 1, the signal output by the power controller 21 is S.
The clamp circuit 10 further includes a clamp controller 11, a control end of the clamp controller 11 is connected to the gate of the clamp switching transistor Q2, and the clamp controller 11 is configured to control the on/off of the clamp switching transistor Q2.
The clamp controller 11 can output a Pulse Width Modulation (PWM) signal to control the on/off of the clamp switching transistor Q2. As shown in fig. 1, the signal output from the clamp controller 11 is Sc.
Optionally, the clamping capacitor Cc includes at least two clamping sub-capacitors, and the at least two clamping sub-capacitors are connected in series. Through the series connection of a plurality of clamp sub-capacitors, the high-voltage resistance of the clamp capacitor Cc can be increased, and the off-voltage spike energy generated by the turn-off of the power switch tube Q1 after the power switch tube Q1 is turned on can be better absorbed.
The switching tube generally has a parasitic diode due to the manufacturing process. As shown in fig. 1, the parasitic power diode corresponding to the power switch Q1 is Ds, the positive electrode of which is connected to the source electrode of the power switch Q1, and the negative electrode of which is connected to the drain electrode of the power switch Q1. The clamp parasitic diode corresponding to the clamp switching tube Q2 is Dc, the positive electrode of Dc is connected with the source electrode of the clamp switching tube Q2, and the negative electrode of Dc is connected with the drain electrode of the clamp switching tube Q2.
The power controller 21 is further configured to control the power switch Q1 to be turned on in a first time interval;
the clamp controller 11 is further configured to control the clamp switching tube Q2 to turn off in a first time interval;
in a first time interval, the rectifier diode D1 is turned off, and the power source Ui charges the resonant inductor Lr and the magnetizing inductor Lm linearly.
The power controller 21 is further configured to control the power switch Q1 to turn off in a second time interval;
the clamp controller 11 is further configured to control the clamp switching tube Q2 to turn off in a first time interval;
in the second time interval, the magnetizing current of the magnetizing inductor Lm charges the equivalent capacitor Cr in a resonant manner, so that the drain-source voltage of the power switch Q1 rises.
The clamping circuit 10 further comprises a clamping parasitic diode Dc, the anode of the clamping parasitic diode Dc is connected with the source electrode of the clamping switching tube Q2, and the cathode of the clamping parasitic diode Dc is connected with the drain electrode of the clamping switching tube Q2;
the power controller 21 is further configured to control the power switch Q1 to turn off in a third time interval;
the clamp controller 11 is further configured to control the clamp switching tube Q2 to turn off in a third time interval;
in a third time interval, when the drain-source voltage of the power switch tube Q1 rises to the first voltage threshold, the clamping parasitic diode is turned on, the voltage of the series branch consisting of the resonant inductor Lr and the magnetizing inductor Lm is clamped at the second voltage threshold, and the magnetizing current of the magnetizing inductor Lm charges the clamping capacitor through the resonant inductor Lr, the magnetizing inductor Lm and the clamping parasitic diode, so that the voltage across the primary coil is reduced.
The power controller 21 is further configured to control the power switching tube Q1 to turn off in a fourth time interval;
the clamp controller 11 is further configured to control the clamp switching tube Q2 to be turned on from off in a fourth time interval;
in a fourth time interval, when the voltage U1 across the primary coil N1 drops to the third voltage threshold, the rectifier diode D1 is turned on, the voltage U1 across the primary coil N1 is clamped to the fourth voltage threshold, and the resonant inductor Lr and the clamping capacitor Cc start to resonate;
the clamp controller 11 is specifically configured to control the clamp switching transistor Q2 to switch from off to on before the current of the clamp capacitor Cc starts to reverse, so that the clamp switching transistor Q2 obtains a zero voltage to turn on ZVS.
The power controller 21 is further configured to control the power switch Q1 to turn off in a fifth time interval;
the clamp controller 11 is further configured to control the clamp switching tube Q2 to turn off in a fifth time interval;
in a fifth time interval, the resonant inductor Lr resonates with the equivalent capacitor Cr.
The power controller 21 is further configured to control the power switch Q1 to turn off in a sixth time interval;
the clamp controller 11 is further configured to control the clamp switching tube Q2 to turn off in a sixth time interval;
in a sixth time interval, the voltage on the resonant inductor Lr is clamped at a fifth voltage threshold;
the power controller 21 is further configured to control the power switching tube Q1 to turn on ZVS at a zero voltage in a seventh time interval;
and the clamp controller 11 is further configured to control the clamp switching tube Q2 to turn off in a seventh time interval.
Referring to fig. 2, fig. 2 is a schematic waveform diagram of a flyback converter according to an embodiment of the present application. The operation of the flyback converter 20 is explained below with reference to fig. 2.
Wherein S in fig. 2 is a signal output by the power controller 21 for controlling the power switch Q1; sc is a signal output by the clamp controller 11 and used for controlling the clamp switching tube Q2; uo is the voltage across the first resistor R1; ucr is the voltage across the equivalent capacitance Cr, iLmThe current value of the magnetizing inductance Lm; the voltage at two ends of the power supply Ui is Ui; u1 is the voltage across primary coil N1; i.e. iLrIs the current value of the resonant inductor Lr; i isspThe peak current of the power switch tube Q1; i.e. icIs the current in the clamping capacitor Cc, Uc is the voltage across the clamping capacitor Cc; i.e. i2Is the current of the rectifying diode D1.
During steady-state operation of the flyback converter 20, each switching cycle is divided into seven switching state phases, and equivalent circuits of the switching states are shown in the figure. The seven switch states are:
① t is t 0-t 1 (namely the first time interval), at the time of t0, S is high level, the power switch tube Q1 is turned on, Sc is low level, the clamp switch tube Q2, the parasitic diode Dc thereof and the rectifier diode D1 are all turned off, and Lm and Lr are charged linearly.
② t is t 1-t 2 (i.e. the second time interval), S is low at time t1, the power switch Q1 is turned off, and the inductor current i is magnetizedLmI.e. resonant inductor current iLrCr is charged in a resonant mode, and the drain-source voltage U of a power switch tube Q1DSApproximately linearly increasing.
③ t is t 2-t 3 (i.e. the third time interval), and at time t2, the drain-source voltage U of the power switch tube Q1DSUp to Ui + UCThe clamping parasitic diode Dc is turned on, the voltage Uc of the voltage of the series branch circuit end consisting of the magnetizing inductance Lr and the resonant inductance Lm is clamped at the two ends of the clamping capacitor Cc and is approximately equal to U0(N1/N2), and the magnetizing inductance current iLmCharging a clamping capacitor Cc through a clamping branch (Cc)>Cr), the voltage U1 across the primary N1 drops to U1 ═ UCLm/(Lr+Lm)。
④ t is t 3-t 4 (i.e. fourth time)Interval) of time; at time t3, U1 has dropped to forward bias the rectifier diode D1 into conduction, then U1 is clamped at-UO (N1/N2), Lr and Cc begin to resonate, and the voltage on Lr is Uc-UO (N1/N2), icDecrease to [ UC-UO (N1/N2)]/Lr at icBefore the reverse direction is started, the clamping switch tube Q2 is turned on, and the clamping switch tube Q2 obtains zero voltage turn-on (ZVS).
⑤ t is t 4-t 5 (i.e. the fifth time interval), at time t4, the clamping switch tube Q2 is turned off, Lr resonates with Cr, and during Cr discharge, U1 is still clamped at the value-Uo (N1/N2).
⑥ t is t 5-t 6 (sixth time interval), and at time t5, the drain-source voltage U of the power switch tube Q1DSAssuming that the Lr stored energy is greater than the Cr stored energy and is sufficient to turn on the parasitic power diode Ds corresponding to the power switch Q1, the voltage on Lr is clamped at the value Ui + Uo (N1/N2), and the current i in the rectifier diode D1 is equal to 02The rate of decrease was:
wherein Lm > Lr;
⑦ t 6-t 7 (i.e. the seventh time interval), and the power switch tube Q1 obtains zero voltage ZVS turn-on at the time of t6 along with iLrRise, i2Gradually decreases, at time t7LrHas risen to a magnetizing current iLmSize of (1), i2At 0, the rectifier diode D1 is reverse biased, U1 changes from-Uo (N1/N2) to Ui, then Lm and Lr charge linearly again and a new PWM switching cycle begins again.
To realize ZVS on of the power switch tube Q1, it must be satisfied that the ① power controller 21 should increase the level of the driving signal during the period from t5 to t6 to turn on the power switch tube Q1, otherwise iLrAfter the zero crossing is positive, Lr will charge Cr again and the power switch Q1 loses ZVS condition. The interval between the turn-on of the power switch tube Q1 and the turn-off of the clamping switch tube Q2 is strictly required, and the value of the interval is not more than one fourth of the resonant period of Lr and Cr, namely
② when the clamp switch Q2 is turned off, the Lr energy storage is not less than the Cr energy storage so as to be able to drain the charge on the Cr, namely:
when the clamping switch tube Q2 is turned off, WLr≥WCr
The active clamping flyback converter has the advantages that ① clamping capacitor Cc absorbs energy in leakage inductance of transformer T and feeds the energy back to the side of a power grid, off-voltage peak caused by the leakage inductance is eliminated, power switch tube Q1 bears minimum voltage stress, ② clamping capacitor Cc and resonance capacitor Cr resonate with resonance inductor Lr, ZVS switching is achieved on power switch tube Q1 and clamping switch tube Q2, ③ resonance inductor Lr enables the rate of change of off-current of rectifier diode D1 to be reduced, and off-loss and switching noise caused by reverse recovery of rectifier diode D1 are reduced.
The magnitude of the magnetizing inductance Lm determines whether the flyback converter is in Continuous Conduction Mode (CCM) or Discontinuous Conduction Mode (DCM). If the system is operating in CCM mode, then
Wherein, PφThe output power when the inductor current is critical and continuous, wherein Fs is the switching frequency, η is the conversion efficiency of the flyback converter, D is the duty ratio of a signal S output by the power controller 21 and used for controlling the power switch tube Q1, and △ D is the lost duty ratio of the signal S.
Based on the design example of the current control active clamp flyback converter internal voltage stabilizing power supply, Ui is 18-32 VDC, three groups of output Uo/Io are +15V/1.0A, -15V/0.2A and +5V/0.4A, rated output power is 20W, FS is 300KHz, Dmax is 0.6 and η is 78.5%, critical continuous power Po, min is 1/6Pomax and Lm is 52.3 μ H, Lr is 2 μ H, Cc is 0.47 μ F and Cf is 100 μ F, three groups of output rectifier diodes, namely SR506, 1N5819 and 1N5819, are respectively used as the power switch tube Q1 and the clamp switch tube Q2, and a current type PWM controller (for example, UC3843) is used as the control circuit.
Referring to fig. 3, fig. 3 is a schematic structural diagram of a flyback converter disclosed in the embodiment of the present application. As shown in fig. 3, the flyback converter includes an input loop, a power converter, and an output loop. The power converter may include, among other things, an active clamp circuit, a high frequency transformer, and a main power switch. The active clamp circuit can be referred to as the clamp circuit 10 shown in fig. 1, and the high-frequency transformer and the main power switch can be referred to as the flyback converter 20 shown in fig. 1. And will not be described in detail herein.
The embodiment of the present invention provides a clamp circuit and a flyback converter, and a specific example is applied to explain the principle and the implementation of the present invention, and the description of the above embodiment is only used to help understand the method and the core idea of the present invention; meanwhile, for the general technical personnel in the field, according to the idea of the present invention, there are changes in the specific implementation and application scope, to sum up, the content of the present specification should not be understood as the limitation of the present invention.
Claims (8)
1. The clamping circuit is applied to a flyback converter, and the flyback converter comprises a transformer, a rectifier diode, a first capacitor, a second capacitor, a resonant inductor, a magnetizing inductor, a first resistor, a power switch tube and an equivalent capacitor corresponding to the power switch tube; the clamping circuit comprises a clamping switch tube and a clamping capacitor; wherein:
the first end of the first capacitor is connected with the first end of the clamping capacitor and the first end of the resonant inductor, the second end of the clamping capacitor is connected with the drain electrode of the clamping switch tube, the source electrode of the clamping switch tube is connected with the drain electrode of the power switch tube and the first end of the equivalent capacitor, and the source electrode of the power switch tube and the second end of the equivalent capacitor are grounded; the second end of the resonance inductor is connected with the first end of the magnetizing inductor and the first end of the primary coil of the transformer, and the second end of the magnetizing inductor is connected with the second end of the primary coil and the source electrode of the clamping switch tube; a first end of a secondary coil of the transformer is connected with an anode of the rectifier diode, a cathode of the rectifier diode is connected with a first end of the second capacitor and a first end of the first resistor, and a second end of the secondary coil of the transformer, a second end of the second capacitor and a second end of the first resistor are grounded; the first end of the first capacitor is connected with the positive end of a power supply, and the second end of the first capacitor is connected with the negative end of the power supply;
when the power supply works and the power switching tube is switched off after being switched on, the clamping capacitor is used for absorbing off-voltage peak energy generated by switching off the power switching tube after being switched on from the resonant inductor and feeding the off-voltage peak energy back to the power supply side;
the flyback converter further comprises a power controller, wherein a control end of the power controller is connected with a grid electrode of the power switch tube, and the power controller is used for controlling the power switch tube to be switched on or switched off;
the clamping circuit further comprises a clamping controller, the control end of the clamping controller is connected with the grid electrode of the clamping switch tube, and the clamping controller is used for controlling the on-off of the clamping switch tube.
2. The clamping circuit of claim 1,
the power controller is also used for controlling the conduction of the power switch tube in a first time interval;
the clamp controller is further used for controlling the clamp switching tube to be turned off in the first time interval;
wherein, in the first time interval, the rectifier diode is turned off, and the power supply linearly charges the resonance inductor and the magnetizing inductor.
3. The clamping circuit of claim 2,
the power controller is also used for controlling the power switch tube to be switched off in a second time interval;
the clamp controller is further used for controlling the clamp switching tube to be turned off in the first time interval;
in the second time interval, the magnetizing current of the magnetizing inductor charges the equivalent capacitor in a resonant mode, so that the drain-source voltage of the power switch tube rises.
4. The clamping circuit of claim 3, further comprising a clamping parasitic diode, wherein an anode of the clamping parasitic diode is connected to the source of the clamping switching tube, and a cathode of the clamping parasitic diode is connected to the drain of the clamping switching tube;
the power controller is also used for controlling the power switch tube to be switched off in a third time interval;
the clamp controller is further used for controlling the clamp switching tube to be turned off in the third time interval;
in the third time interval, when the drain-source voltage of the power switch tube rises to a first voltage threshold, the clamping parasitic diode is turned on, the voltage of a series branch formed by the resonant inductor and the magnetizing inductor is clamped at a second voltage threshold, and the magnetizing current of the magnetizing inductor charges the clamping capacitor through the resonant inductor, the magnetizing inductor and the clamping parasitic diode, so that the voltage at two ends of the primary coil is reduced.
5. The clamping circuit of claim 4,
the power controller is also used for controlling the power switch tube to be switched off in a fourth time interval;
the clamp controller is further used for controlling the clamp switching tube to be switched on from off in the fourth time interval;
wherein, in the fourth time interval, when the voltage across the primary coil drops to a third voltage threshold, the rectifier diode is turned on, the voltage across the primary coil is clamped to a fourth voltage threshold, and the resonant inductor and the clamping capacitor start to resonate;
the clamp controller is specifically configured to control the clamp switching tube to be turned on from an off state before the current of the clamp capacitor starts to reverse, so that the clamp switching tube obtains a zero voltage and turns on ZVS.
6. The clamping circuit of claim 5,
the power controller is also used for controlling the power switch tube to be switched off in a fifth time interval;
the clamp controller is further used for controlling the clamp switching tube to be turned off in the fifth time interval;
wherein, in the fifth time interval, the resonance inductance resonates with the equivalent capacitance.
7. The clamping circuit of claim 6,
the power controller is also used for controlling the power switch tube to be switched off in a sixth time interval;
the clamp controller is further used for controlling the clamp switching tube to be turned off in the sixth time interval;
wherein, in the sixth time interval, the voltage across the resonant inductor is clamped at a fifth voltage threshold;
the power controller is further used for controlling the power switching tube to switch on ZVS at a seventh time interval under zero voltage;
and the clamp controller is also used for controlling the clamp switching tube to be switched off in the seventh time interval.
8. A flyback converter characterized in that it comprises a clamp circuit as claimed in any one of claims 1 to 7.
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN113381615A (en) * | 2020-07-14 | 2021-09-10 | 成都芯源***有限公司 | Energy recovery circuit and method for isolating voltage converter |
| WO2021203870A1 (en) * | 2020-04-10 | 2021-10-14 | 华为技术有限公司 | Charging apparatus, control method therefor, and charging system |
| CN113708640A (en) * | 2021-08-25 | 2021-11-26 | 深圳中科乐普医疗技术有限公司 | Active clamping flyback converter, control method thereof and switching power supply system |
| CN114123745A (en) * | 2021-10-26 | 2022-03-01 | 深圳市联洲国际技术有限公司 | Efficient flyback circuit for leakage inductance and control method thereof |
| WO2022077751A1 (en) * | 2020-10-15 | 2022-04-21 | 华源智信半导体(深圳)有限公司 | Switching power supply and electronic device |
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2019
- 2019-04-30 CN CN201920630508.8U patent/CN210120487U/en active Active
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2021203870A1 (en) * | 2020-04-10 | 2021-10-14 | 华为技术有限公司 | Charging apparatus, control method therefor, and charging system |
| CN113381615A (en) * | 2020-07-14 | 2021-09-10 | 成都芯源***有限公司 | Energy recovery circuit and method for isolating voltage converter |
| WO2022077751A1 (en) * | 2020-10-15 | 2022-04-21 | 华源智信半导体(深圳)有限公司 | Switching power supply and electronic device |
| CN113708640A (en) * | 2021-08-25 | 2021-11-26 | 深圳中科乐普医疗技术有限公司 | Active clamping flyback converter, control method thereof and switching power supply system |
| CN113708640B (en) * | 2021-08-25 | 2023-01-20 | 深圳中科乐普医疗技术有限公司 | Active clamping flyback converter, control method thereof and switching power supply system |
| CN114123745A (en) * | 2021-10-26 | 2022-03-01 | 深圳市联洲国际技术有限公司 | Efficient flyback circuit for leakage inductance and control method thereof |
| CN114123745B (en) * | 2021-10-26 | 2023-10-13 | 深圳市联洲国际技术有限公司 | Efficient flyback circuit for leakage inductance and control method thereof |
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