CN107733235A - Flyback active clamp circuit and its control method - Google Patents
Flyback active clamp circuit and its control method Download PDFInfo
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- CN107733235A CN107733235A CN201711019654.9A CN201711019654A CN107733235A CN 107733235 A CN107733235 A CN 107733235A CN 201711019654 A CN201711019654 A CN 201711019654A CN 107733235 A CN107733235 A CN 107733235A
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- Prior art keywords
- switch pipe
- voltage
- master power
- power switch
- electric capacity
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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
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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
- H02M1/0048—Circuits or arrangements for reducing losses
- H02M1/0054—Transistor switching losses
- H02M1/0058—Transistor switching losses by employing soft switching techniques, i.e. commutation of transistors when applied voltage is zero or when current flow is zero
-
- 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 kind of flyback active clamp circuit and its control method, the flyback active clamp circuit includes inverse-excitation type switch power-supply, also include the first electric capacity and first switch pipe, one end of first electric capacity and the hot end of input power connect, the other end is connected with the first end of the first switch pipe, and the second end of the first switch pipe is connected on the master power switch pipe and the common port of the primary side winding；The time turned off according to the conducting of master power switch pipe and first switch pipe and the voltage at the magnetizing inductance both ends, adjust the shut-off moment of first switch pipe.The present invention can reduce the turn-on consumption of master power switch pipe, be also beneficial to the reduction of conduction loss.
Description
Technical field
The present invention relates to a kind of electric and electronic technical field, more particularly to a kind of flyback active clamp circuit and its controlling party
Method.
Background technology
Inverse-excitation type switch power-supply is a kind of isolation type switching power supply, is widely used in AC DC (AC/DC) and direct current is straight
(DC/DC) conversion is flowed, and provides and is dielectrically separated between input stage and output stage.Inverse-excitation type switch power-supply includes master power switch
Pipe, transformer and secondary rectifying tube, the transformer include primary side winding and vice-side winding, the master power switch pipe with it is described
Primary side winding is connected, and the secondary rectifying tube is connected with the vice-side winding, and master power switch pipe is controlled by primary-side-control circuit
On off state, positioned at secondary secondary rectifying tube master power switch pipe shut-off after turn on afterflow.
Active clamp topological structure is drain electrode one electric capacity of connection in the master power switch pipe of inverse-excitation type switch power-supply,
A switching tube is connected between the drain electrode of master power switch pipe and electric capacity, described electric capacity is connected with input power.Main power is opened
When being turned off after the pipe conducting of pass, drain shutdown moment, and the momentary spikes and higher hamonic wave for turning off waveform are capacitively coupled to power supply
On, reach the purpose of master power switch pipe drain voltage clamper, reduce the turn-off power loss of master power switch pipe, switched so as to reduce
The power attenuation of power supply.
As shown in figure 1, a kind of flyback active clamp circuit is illustrated, when system is worked under BCM or DCM patterns,
When each switch periods start, magnetizing current is close to zero.Prior art generally by such as Fig. 2 mode controlling switch pipe
MA's turns on and off, when master power switch pipe M0 is opened, switching tube MA shut-offs, and when master power switch pipe M0 is turned off, switching tube
MA is open-minded.
LMFor the magnetizing inductance in primary side winding, prior art utilizes the pass of the control mode controlling switch pipe MA in Fig. 2
It is disconnected, due to before master power switch pipe M0 being opened, the accurate control at moment not being turned off for switching tube MA, is likely to result in
LMUpper negative current is excessive and increases the technical problem of conduction loss.
The content of the invention
In view of this, main power is reduced by the shut-off moment of controlling switch pipe opened it is an object of the invention to provide a kind of
The flyback active clamp circuit of pipe turn-on consumption is closed, solves the big technology of master power switch pipe turn-on consumption existing for prior art
Problem.
To achieve the above object, the invention provides a kind of flyback active clamp circuit, including master power switch pipe, transformation
Device and secondary rectifying tube, the transformer include primary side winding and vice-side winding, and the primary side winding includes magnetizing inductance, described
Master power switch pipe is connected with the primary side winding, and the secondary rectifying tube is connected with the vice-side winding, by primary-side-control electricity
Road controls the on off state of master power switch pipe, and secondary rectifying tube turns on afterflow after the shut-off of master power switch pipe；
The flyback active clamp circuit also includes the first electric capacity and first switch pipe, one end of first electric capacity with it is defeated
Entering the hot end connection of power supply, the other end is connected with the first end of the first switch pipe, and the second of the first switch pipe
End is connected on the master power switch pipe and the common port of the primary side winding；
The time turned off according to the conducting of master power switch pipe and first switch pipe and the voltage at the magnetizing inductance both ends, are adjusted
Save the shut-off moment of first switch pipe.
Optionally, after the shut-off of first switch pipe, the voltage of the common port of detection master power switch pipe and primary side winding or
Voltage change ratio, when a period of time master power switch pipe and the common port of primary side winding voltage or master power switch pipe with
When the voltage change ratio of the common port of primary side winding reaches respective threshold, then first switch pipe next cycle is advanced or delayed
The shut-off moment.
Optionally, the flyback active clamp circuit also includes being used for the switch management and control for controlling the first switch pipe shut-off
Circuit processed, the switch controlled circuit include the second electric capacity, the voltage at detection magnetizing inductance both ends, and obtain characterizing magnetization electricity
Feel the current signal of both end voltage, during the conducting of master power switch pipe and first switch pipe turn off, the current signal is to institute
The charging of the second electric capacity is stated, during the shut-off of master power switch pipe and first switch pipe turn on, the current signal is to described second
Electric capacity discharges, and in discharge process, when the voltage on the second electric capacity is down to corresponding reference signal, then controls the first switch pipe
Shut-off.
Optionally, the ON-OFF control circuit also includes assists winding, first resistor and comparison circuit, the assists winding
With described transformer coupled, the first resistor is connected with the assists winding to sample the voltage of assists winding, and described first
Ohmically voltage characterizes the voltage at the magnetizing inductance both ends, samples the electric current in the first resistor, obtains the sign
The current signal of magnetizing inductance both end voltage, the current signal transport to second electric capacity, the voltage on second electric capacity
The first input end of the comparison circuit is accessed, the reference signal accesses the second input of the comparison circuit, the ratio
Output end compared with circuit is connected with the control terminal of the first switch pipe.
Optionally, after the shut-off of first switch pipe, before the conducting of master power switch pipe, the second electric capacity both end voltage is kept
Equal to initial voltage.
Optionally, when the voltage or voltage change ratio of the master power switch pipe and the common port of primary side winding are less than corresponding
During threshold value, by increasing the reference signal come the shut-off moment of the first switch pipe in advance；When the master power switch pipe
When being higher than respective threshold with the voltage or voltage change ratio of the common port of primary side winding, postponed by reducing the reference signal
The shut-off moment of the first switch pipe.
Optionally, when the voltage or voltage change ratio of the master power switch pipe and the common port of primary side winding are less than corresponding
During threshold value, by reducing second electric capacity or increase to the discharge current of the second electric capacity come the pass of the first switch pipe in advance
The disconnected moment；When the voltage or voltage change ratio of the master power switch pipe and the common port of primary side winding are higher than respective threshold,
By increasing second electric capacity or reducing to the discharge current of the second electric capacity to postpone the shut-off moment of the first switch pipe.
The present invention also provides a kind of control method of flyback active clamp circuit,
Based on the flyback active clamp circuit, the flyback active clamp circuit includes master power switch pipe, transformer
With secondary rectifying tube, the transformer includes primary side winding and vice-side winding, and the primary side winding includes magnetizing inductance, the master
Power switch pipe is connected with the primary side winding, and the secondary rectifying tube is connected with the vice-side winding, by primary-side-control circuit
The on off state of master power switch pipe is controlled, secondary rectifying tube turns on afterflow after the shut-off of master power switch pipe；
The flyback active clamp circuit also includes the first electric capacity and first switch pipe, one end of first electric capacity with it is defeated
Entering the hot end connection of power supply, the other end is connected with the first end of the first switch pipe, and the second of the first switch pipe
End is connected on the master power switch pipe and the common port of the primary side winding；
The time turned off according to the conducting of master power switch pipe and first switch pipe and the voltage at the magnetizing inductance both ends, are adjusted
Save the shut-off moment of first switch pipe.
Optionally, after the shut-off of first switch pipe, the voltage of the common port of detection master power switch pipe and primary side winding or
Voltage change ratio, when a period of time master power switch pipe and the common port of primary side winding voltage or master power switch pipe with
When the voltage change ratio of the common port of primary side winding reaches respective threshold, then first switch pipe next cycle is advanced or delayed
The shut-off moment.
Optionally, the flyback active clamp circuit also includes being used for the switch management and control for controlling the first switch pipe shut-off
Circuit processed, the switch controlled circuit include the second electric capacity, the voltage at detection magnetizing inductance both ends, and obtain characterizing magnetization electricity
Feel the current signal of both end voltage, during the conducting of master power switch pipe and first switch pipe turn off, the current signal is to institute
The charging of the second electric capacity is stated, during the shut-off of master power switch pipe and first switch pipe turn on, the current signal is to described second
Electric capacity discharges, and in discharge process, when the voltage on the second electric capacity is down to corresponding reference signal, then controls the first switch pipe
Shut-off.
Optionally, after the shut-off of first switch pipe, before the conducting of master power switch pipe, the second electric capacity both end voltage is kept
Equal to initial voltage.
Compared with prior art, the technical scheme of the present invention has advantages below：The present invention is directed to be opened by control first
Close the shut-off moment of pipe so that before the conducting of master power switch pipe, to master power switch pipe and the common port of primary side winding (main work(
The drain electrode of rate switching tube) electric discharge, so as to control there is slight negative current in magnetizing inductance.The present invention can reduce main power and open
The turn-on consumption of pipe is closed, is also beneficial to the reduction of conduction loss.
Brief description of the drawings
Fig. 1 is the electrical block diagram of prior art flyback active clamp circuit；
Fig. 2 is the control waveform diagram of prior art flyback active clamp circuit；
Fig. 3 is the electrical block diagram of flyback active clamp circuit of the present invention；
Fig. 4 is the waveform diagram of flyback active clamp circuit of the present invention.
Embodiment
The preferred embodiments of the present invention are described in detail below in conjunction with accompanying drawing, but the present invention is not restricted to these
Embodiment.The present invention covers any replacement made in the spirit and scope of the present invention, modification, equivalent method and scheme.
Thoroughly understand in order that the public has to the present invention, be described in detail in present invention below preferred embodiment specific
Details, and description without these details can also understand the present invention completely for a person skilled in the art.
More specifically description is of the invention by way of example referring to the drawings in the following passage.It should be noted that accompanying drawing is adopted
Non- accurately ratio is used with more simplified form and, only to convenience, lucidly aid in illustrating the embodiment of the present invention
Purpose.
As shown in figure 3, the circuit structure of flyback active clamp circuit of the present invention is illustrated, including master power switch pipe M0,
Transformer and secondary rectifying tube D1, the transformer include primary side winding L1 and vice-side winding L2, and the primary side winding L1 includes
Magnetizing inductance LM, the master power switch pipe M0 is connected with the primary side winding L1, the secondary rectifying tube D1 and the secondary
Winding L2 connections, master power switch pipe M0 on off state is controlled by primary-side-control circuit, and secondary rectifying tube D1 opens in main power
Afterflow is turned on after closing pipe M0 shut-offs；
The flyback active clamp circuit also includes the first electric capacity C1 and first switch pipe MA, the one of the first electric capacity C1
End is connected with the hot end of input power, the other end and the first switch pipe MAFirst end connection, the first switch
Pipe MAThe second end be connected on the master power switch pipe M0 and the primary side winding L1 common port；
According to master power switch pipe M0 conductings and first switch pipe MAThe time of shut-off and the magnetizing inductance LMThe electricity at both ends
Pressure, regulation first switch pipe MAThe shut-off moment.Mainly realized using voltage-second balance, be specially：As master power switch pipe M0
Conducting, first switch pipe MADuring shut-off, magnetizing inductance LMOn voltage be Vin-VSW, when master power switch pipe M0 turn off, first
Switching tube MAWhen opening, LMOn voltage be VA, utilize LMThe voltage-second balance of upper voltage determines MATurn-off time.
From circuit realiration, then by switch controlled circuit realiration, as shown in figure 3, the switch controlled circuit includes
Second electric capacity C2, detection magnetizing inductance LMThe voltage at both ends, and obtain characterizing magnetizing inductance LMThe current signal of both end voltage,
Master power switch pipe M0 is turned on and first switch pipe MADuring shut-off, the current signal charges to the second electric capacity C2,
Master power switch pipe M0 is turned off and first switch pipe MADuring conducting, the current signal discharges the second electric capacity C2,
In discharge process, when the voltage on the second electric capacity C2 is down to corresponding reference signal Vref, then the first switch pipe M0 is controlled to close
It is disconnected.
For magnetizing inductance LMThe detection of both end voltage has a variety of implementations, and the present embodiment utilizes assists winding, described
ON-OFF control circuit also includes assists winding LN, first resistor R1 and comparison circuit U1, the assists winding LNWith the transformer
Coupling, the first resistor R1 are connected with the assists winding L2 to sample assists winding LNVoltage, the first resistor R1
On voltage characterize the magnetizing inductance LMThe voltage at both ends, samples the electric current on the first resistor R1, during specific implementation, leads to
Over-sampling to electric current adjusted to adjust current source i1, the sampled current regulations of current source i1, such as passing ratio K
Section, obtain the sign magnetizing inductance LMThe current signal of both end voltage, the current signal transport to the second electric capacity C2, institute
The first input end that the voltage on the second electric capacity C2 accesses the comparison circuit U1 is stated, the reference signal Vref accesses the ratio
Compared with the second input of circuit U 1, the output end of the comparison circuit U1 and the first switch pipe MAControl terminal connection.Should
The principle of circuit mainly utilizes the form to capacitor charge and discharge, according to master power switch pipe M0 conductings and first switch pipe MAShut-off
Time, the magnetizing inductance LMThe voltage at both ends, regulation first switch pipe MAThe shut-off moment, release first switch pipe MALeakage
The energy of pole, to reduce turn-on consumption.After the shut-off of first switch pipe, before the conducting of master power switch pipe, second electricity is kept
Holding both end voltage and be equal to initial voltage, initial voltage is setting value, and its size can be configured according to practical application, for example,
Under discontinuous conduction mode, magnetizing inductance LMOn do not need negative current, otherwise can increase conduction loss on the contrary, so, it is described just
Beginning voltage can be arranged to be slightly less than the reference signal, can so cause before master power switch pipe is opened, magnetizing inductance
Upper no negative current, help to reduce conduction loss；Under continuous conduction mode so that before master power switch pipe is opened, control
Magnetizing inductance L processedMIt is upper that there is slight negative current, using the negative current to VSWDischarged, M0 turn-on consumption can be reduced,
Therefore, the initial voltage can be arranged to be slightly larger than the reference signal, so as to realize LMOn have slight negative current.
In Fig. 3, comparison circuit U1 output end and first switch pipe MAControl terminal connection only to facilitate signal, real
The two in border is not necessarily directly connected to, and centre has control or logical transition circuit etc., is explained herein.
Further, in order to prevent in first switch pipe MAIt is excessive and produce energy loss to occur negative current after shut-off, therefore
Judged by the voltage decrease speed of master power switch pipe and the common port of primary side winding, if MAOccur negative electricity after shut-off to flow through
The voltage of big then described common port declines comparatively fast, can be judged by least two means.Firstth, according to the common port
Voltage Vsw at voltage change ratioTo judge, when the voltage or voltage change ratio are less than respective threshold, due to this
Place's voltage change ratio is negative value, although its absolute value is bigger than normal, is now still treated according to negative, when it is less than corresponding threshold
During value, then shut-off moment in first switch pipe next cycle in advance.Secondth, a period is preset, within the period
If the voltage Vsw that common port occurs is less than respective threshold, in advance the shut-off moment in first switch pipe next cycle.More than
Two kinds of means can have differences from concrete implementation circuit, but be inherently the rate of change for detecting voltage.So as to realize master
Before power switch pipe M0 is opened, magnetizing inductance LMIt is upper that there is negative current, and the negative current is less big, is just used to give voltage VSWPut
Electricity, reduce master power switch pipe M0 turn-on consumption, conduction loss will not be increased again.It is embodied in Fig. 3 circuit, that is, works as voltage
VSWFall off rateReach a certain threshold value or VSWWhen dropping to the time of certain threshold value, judge that the value of negative current is excessive, then adjust
High reference signal Vref value, to shift to an earlier date the shut-off moment in first switch pipe next cycle so that negative current diminishes.More than
Simply with less than being described in case of respective threshold, when higher than the respective threshold, then described first can be postponed
The shut-off moment in switching tube next cycle.I.e. when the voltage or voltage of the master power switch pipe and the common port of primary side winding become
When rate is less than respective threshold, by increasing the reference signal come the shut-off moment of the first switch pipe in advance；When described
When the voltage or voltage change ratio of master power switch pipe and the common port of primary side winding are higher than respective threshold, by reducing the ginseng
Signal is examined to postpone the shut-off moment of the first switch pipe.Except that by way of adjusting the reference signal, can also adopt
Realized with the second electric capacity of regulation or to the discharge current of the second electric capacity, i.e., when the master power switch pipe and the public affairs of primary side winding
When the voltage or voltage change ratio held altogether are less than respective threshold, the second electric capacity is put by reducing second electric capacity or increase
Electric current (being realized by the proportionality coefficient for adjusting sample rate current control electric current source i1) is come the shut-off of the first switch pipe in advance
Moment；When the voltage or voltage change ratio of the master power switch pipe and the common port of primary side winding are higher than respective threshold, lead to
Cross and increase second electric capacity or reduce to the discharge current of the second electric capacity to postpone the shut-off moment of the first switch pipe.
As shown in figure 4, illustrate the work wave of flyback active clamp circuit of the present invention.The body of voltage-second balance in Fig. 4
It is now S1=S2, S1, S2 are respectively the area of respective regions, the electric current iL in Fig. 4MTo pass through LMOn electric current, because weber puts down
The characteristic of weighing apparatus, therefore iLM is equal in the current value at t3 moment with it in the electric current at t1 moment, when t3 is the shut-off of first switch pipe
Carve.The waveform of voltage and current value in figure is signal, in practice, electric current iLMNot necessarily linear change, magnetization electricity
Feel LMOn voltage VLMIt is not constant pressure, illustrates in figure only to facilitate illustrating, without being construed as limiting the invention yet.
Although embodiment is separately illustrated and illustrated above, it is related to the common technology in part, in ordinary skill
Personnel apparently, can be replaced and integrate between the embodiments, be related to one of embodiment and the content recorded is not known, then
Refer to another embodiment on the books.
Embodiments described above, the restriction to the technical scheme protection domain is not formed.It is any in above-mentioned implementation
Modifications, equivalent substitutions and improvements made within the spirit and principle of mode etc., should be included in the protection model of the technical scheme
Within enclosing.
Claims (11)
1. a kind of flyback active clamp circuit, including master power switch pipe, transformer and secondary rectifying tube, the transformer include
Primary side winding and vice-side winding, the primary side winding include magnetizing inductance, and the master power switch pipe connects with the primary side winding
Connecing, the secondary rectifying tube is connected with the vice-side winding, and the on off state of master power switch pipe is controlled by primary-side-control circuit,
Secondary rectifying tube turns on afterflow after the shut-off of master power switch pipe；
The flyback active clamp circuit also includes the first electric capacity and first switch pipe, one end and the input electricity of first electric capacity
The hot end connection in source, the other end are connected with the first end of the first switch pipe, and the second end of the first switch pipe connects
It is connected on the master power switch pipe and the common port of the primary side winding；
The time turned off according to the conducting of master power switch pipe and first switch pipe and the voltage at the magnetizing inductance both ends, regulation the
The shut-off moment of one switching tube.
2. flyback active clamp circuit according to claim 1, it is characterised in that after the shut-off of first switch pipe, detection
The voltage or voltage change ratio of the common port of master power switch pipe and primary side winding, when a period of time master power switch pipe with
The voltage of the common port of primary side winding reaches the voltage change of respective threshold or master power switch pipe and the common port of primary side winding
When rate reaches respective threshold, then the shut-off moment in first switch pipe next cycle is advanced or delayed.
3. flyback active clamp circuit according to claim 1 or 2, it is characterised in that the flyback active clamp circuit
Also include being used for the switch controlled circuit for controlling the first switch pipe shut-off, the switch controlled circuit includes the second electricity
Hold, the voltage at detection magnetizing inductance both ends, and obtain characterizing the current signal of magnetizing inductance both end voltage, in master power switch pipe
Conducting and first switch pipe turn off during, the current signal charge to second electric capacity, master power switch pipe turn off and
During first switch pipe turns on, the current signal discharges second electric capacity, in discharge process, the electricity on the second electric capacity
During pressure drop to corresponding reference signal, then the first switch pipe is controlled to turn off.
4. flyback active clamp circuit according to claim 3, it is characterised in that the ON-OFF control circuit also includes auxiliary
Winding, first resistor and comparison circuit are helped, the assists winding is with described transformer coupled, the first resistor and the auxiliary
To sample the voltage of assists winding, the voltage in the first resistor characterizes the voltage at the magnetizing inductance both ends for winding connection,
The electric current in the first resistor is sampled, obtains the current signal of the sign magnetizing inductance both end voltage, the current signal
Transport to second electric capacity, the voltage on second electric capacity accesses the first input end of the comparison circuit, described with reference to letter
Second input of number access comparison circuit, the output end of the comparison circuit and the control terminal of the first switch pipe connect
Connect.
5. flyback active clamp circuit according to claim 4, it is characterised in that after the shut-off of first switch pipe, main work(
Before the conducting of rate switching tube, the second electric capacity both end voltage is kept to be equal to initial voltage.
6. flyback active clamp circuit according to claim 2, it is characterised in that when the master power switch pipe and primary side
When the voltage or voltage change ratio of the common port of winding are less than respective threshold, by increasing the reference signal come described in advance
The shut-off moment of one switching tube；When the voltage or voltage change ratio of the master power switch pipe and the common port of primary side winding are higher than
During respective threshold, postpone the shut-off moment of the first switch pipe by reducing the reference signal.
7. flyback active clamp circuit according to claim 3, it is characterised in that when the master power switch pipe and primary side
When the voltage or voltage change ratio of the common port of winding are less than respective threshold, by reducing second electric capacity or increase to second
The discharge current of electric capacity carrys out the shut-off moment of the first switch pipe in advance；When the master power switch pipe and the public affairs of primary side winding
When the voltage or voltage change ratio held altogether are higher than respective threshold, the second electric capacity is put by increasing second electric capacity or reducing
Electric current postpones the shut-off moment of the first switch pipe.
8. a kind of control method of flyback active clamp circuit, it is characterised in that described based on the flyback active clamp circuit
Flyback active clamp circuit includes master power switch pipe, transformer and secondary rectifying tube, the transformer include primary side winding and
Vice-side winding, the primary side winding include magnetizing inductance, and the master power switch pipe is connected with the primary side winding, the secondary
Rectifying tube is connected with the vice-side winding, and the on off state of master power switch pipe, secondary rectifying tube are controlled by primary-side-control circuit
Afterflow is turned on after the shut-off of master power switch pipe；
The flyback active clamp circuit also includes the first electric capacity and first switch pipe, one end and the input electricity of first electric capacity
The hot end connection in source, the other end are connected with the first end of the first switch pipe, and the second end of the first switch pipe connects
It is connected on the master power switch pipe and the common port of the primary side winding；
The time turned off according to the conducting of master power switch pipe and first switch pipe and the voltage at the magnetizing inductance both ends, regulation the
The shut-off moment of one switching tube.
9. the control method of flyback active clamp circuit according to claim 8, after the shut-off of first switch pipe, detection master
The voltage or voltage change ratio of power switch pipe and the common port of primary side winding, as a period of time master power switch Guan Yuyuan
The voltage of the common port of side winding reaches the voltage change ratio of respective threshold or master power switch pipe and the common port of primary side winding
When reaching respective threshold, then the shut-off moment in first switch pipe next cycle is advanced or delayed.
10. the control method of flyback active clamp circuit according to claim 9, it is characterised in that the flyback is active
Clamp circuit also includes being used for the switch controlled circuit for controlling the first switch pipe shut-off, the switch controlled circuit bag
The second electric capacity, the voltage at detection magnetizing inductance both ends are included, and obtains characterizing the current signal of magnetizing inductance both end voltage, in main work(
During rate switching tube turns on and first switch pipe turns off, the current signal charges to second electric capacity, in master power switch
During pipe turns off and first switch pipe turns on, the current signal discharges second electric capacity, in discharge process, the second electricity
When voltage in appearance is down to corresponding reference signal, then the first switch pipe is controlled to turn off.
11. the control method of flyback active clamp circuit according to claim 9, it is characterised in that in first switch pipe
After shut-off, before the conducting of master power switch pipe, the second electric capacity both end voltage is kept to be equal to the initial voltage.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201711019654.9A CN107733235B (en) | 2017-10-27 | 2017-10-27 | Flyback active clamp circuit and control method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201711019654.9A CN107733235B (en) | 2017-10-27 | 2017-10-27 | Flyback active clamp circuit and control method thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN107733235A true CN107733235A (en) | 2018-02-23 |
| CN107733235B CN107733235B (en) | 2023-08-29 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201711019654.9A Active CN107733235B (en) | 2017-10-27 | 2017-10-27 | Flyback active clamp circuit and control method thereof |
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| Country | Link |
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| CN (1) | CN107733235B (en) |
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| CN108809107A (en) * | 2018-07-13 | 2018-11-13 | 深圳南云微电子有限公司 | A kind of method and circuit of the self adaptive control of active clamp flyback converter |
| CN108988652A (en) * | 2018-09-10 | 2018-12-11 | 杰华特微电子（张家港）有限公司 | Flyback active clamp circuit and its control method |
| CN109245569A (en) * | 2018-09-18 | 2019-01-18 | 西安矽力杰半导体技术有限公司 | Inverse excitation type converter and its control circuit |
| CN109546863A (en) * | 2018-12-11 | 2019-03-29 | 杰华特微电子（杭州）有限公司 | A kind of flyback active clamp circuit and its control method |
| CN113972816A (en) * | 2020-12-14 | 2022-01-25 | 矽力杰半导体技术(杭州)有限公司 | Control circuit and switching converter using same |
| US11843318B2 (en) | 2021-02-10 | 2023-12-12 | Huawei Digital Power Technologies Co., Ltd. | Converter and power adapter for reducing energy loss |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN108809107A (en) * | 2018-07-13 | 2018-11-13 | 深圳南云微电子有限公司 | A kind of method and circuit of the self adaptive control of active clamp flyback converter |
| CN108988652A (en) * | 2018-09-10 | 2018-12-11 | 杰华特微电子（张家港）有限公司 | Flyback active clamp circuit and its control method |
| CN109245569A (en) * | 2018-09-18 | 2019-01-18 | 西安矽力杰半导体技术有限公司 | Inverse excitation type converter and its control circuit |
| CN109245569B (en) * | 2018-09-18 | 2020-04-24 | 西安矽力杰半导体技术有限公司 | Flyback converter and control circuit thereof |
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| US11671020B2 (en) | 2018-09-18 | 2023-06-06 | Silergy Semiconductor Technology (Hangzhou) Ltd | Flyback converter, control circuit and control method thereof |
| CN109546863A (en) * | 2018-12-11 | 2019-03-29 | 杰华特微电子（杭州）有限公司 | A kind of flyback active clamp circuit and its control method |
| CN113972816A (en) * | 2020-12-14 | 2022-01-25 | 矽力杰半导体技术(杭州)有限公司 | Control circuit and switching converter using same |
| US11843318B2 (en) | 2021-02-10 | 2023-12-12 | Huawei Digital Power Technologies Co., Ltd. | Converter and power adapter for reducing energy loss |
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