CN1938931B - Soft switch power converter with power-saving member - Google Patents
Soft switch power converter with power-saving member Download PDFInfo
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- CN1938931B CN1938931B CN2004800427529A CN200480042752A CN1938931B CN 1938931 B CN1938931 B CN 1938931B CN 2004800427529 A CN2004800427529 A CN 2004800427529A CN 200480042752 A CN200480042752 A CN 200480042752A CN 1938931 B CN1938931 B CN 1938931B
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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
- H02M1/34—Snubber circuits
-
- 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
- H02M3/337—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 in push-pull configuration
- H02M3/3376—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 in push-pull configuration with automatic control of output voltage or current
-
- 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
- H02M1/0003—Details of control, feedback or regulation circuits
- H02M1/0032—Control circuits allowing low power mode operation, e.g. in standby mode
-
- 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
- H02M1/34—Snubber circuits
- H02M1/342—Active non-dissipative snubbers
-
- 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
Abstract
A pulse width modulated soft-switching power converter, having a pair of main switches and a pair of auxiliary switches coupled to the primary winding of the transformer. The main switches and auxiliary switches intermittently conduct an input voltage source to the primary winding to operate the soft-switching power converter in four operation stages in each switching cycle. The main switches conduct the input voltage source to the transformer in a first operation stage. In a second operation stage, the conduction is cut off. The transformer operates as an inductor with the auxiliary switchesswitched on under zero-voltage or zero-current switching mode in a third operation stage. In the fourth operation stage, the auxiliary switches are switched off, whereby the flyback energy achieves the zero-voltage transition. A zero-voltage-detection is employed to optimize the zero-voltage switching. The switching frequency is decreased in response to the decrease of the load. Furthermore, the auxiliary switching is restricted in accordance with the decrease of the load. Therefore reducing the power consumption in the light load and no load conditions.
Description
Technical field
The present invention relates generally to a kind of pulse width modulation (pulse width modulation, PWM) power converter, and or rather, the present invention relates to a kind of pulse width modulation power transducer that uses zero voltage switching technology and power-saving member.
Background technology
Power converter has been usually used in converting unregulated power source to constant voltage source.Transformer with winding and secondary winding is the core of most of power converters.Usually, switchgear is connected to winding and transfers to the energy of secondary winding and from described secondary winding output with control from winding.Current, under the control of switchgear, size that the pulse width modulation power transducer can be less and weight and under constant high-frequency, operate.Yet this power converter stands handoff loss, component stress and noise and electromagnetic interference (electromagneticit inerference, problem EMI).
For solving the handoff loss problem of pulse width modulation power transducer, proposed to be used for the phase shifted version of operating in soft handover, in particular for the high-frequency power transfer.For example, full-bridge (full-bridge, FB) quasi-resonance zero voltage switching (zero-voltage switching, ZVS) technology has disclosed and has been to give on August 8th, 1989 Christopher P.Henze, the U.S. the 4th of Ned Mohan and John G.Hayes, 855, No. 888 patents " Constant frequencyresonant power converter with zero-voltage switching ", give the United States Patent (USP) the 5th of Guichao C Hua and Fred C.Lee August 15 nineteen ninety-five, 442, No. 540 " Soft-switching PWM converters " and in " the Soft-switched full-bridgeconverters " that disclosed on March 12nd, 2002 by YungtaekJang and Milan M.Jovanovic.Gave the U.S. the 5th of F.Don Tan on October 26th, 1999 in fourth, 973, No. 939 patents " Double forward converter with soft-PWM switching " and give the U.S. the 6th of Simon Fraidlin and Anatoliy Polikarpov February 20 calendar year 2001, the active-clamp technology has been used for normal shock zero voltage switching power converter in 191, No. 960 patents " Active clamp isolated power converter and methodof operating thereof ".Be to give on May 30th, 2000 U.S. the 6th of Rui Liu, 069, in No. 798 patents " Asymmetrical power converter and method of operation thereof ", developed and be used for half-bridge (half-bridge, HB) Tuo Pu asymmetric scheme.
In various zero voltage switching power converters, the parasitic leakage inductor of transformer or the magnetic assembly that at least one is extra produce loop current as resonant inductor or switch, so that realize Zero voltage transition and handover operation.Although the parasitic leakage inductor of transformer or extra magnetic assembly provide the help of Zero voltage transition and switching, therefore increase switch stress and noise.In addition, in this approach, obviously higher under underload or zero load condition by the caused power consumption of loop current.
Summary of the invention
The invention provides a kind of zero voltage switching pulse width modulation power transducer that is used for high frequencies of operation.Described zero voltage switching pulse width modulation power transducer is operated under constant high-frequency with low handoff loss, low stress and low noise.
The present invention further provides and a kind ofly realize Zero voltage transition and handover operation and need not to use the zero voltage switching pulse width modulation power transducer of the electric leakage inductor of extra magnetic machine or transformer.
The present invention also provides a kind of relative lower powered zero voltage switching pulse width modulation power transducer that consumes under underload and zero load condition.
In addition, the invention provides a kind of controlling schemes that is used for the soft switch of optimized power transducer.
Zero voltage switching pulse width modulation power transducer provided by the present invention comprises transformer, primary circuit and secondary circuit.Described transformer has a winding that is coupled to described primary circuit and the secondary winding that is coupled to described secondary circuit.Described zero voltage switching pulse width modulation further comprises feedback circuit, and its output of being coupled to described secondary circuit is to produce feedback voltage.Described primary circuit further comprises the controller that is coupled to described feedback circuit.Described controller can be operated in response to described feedback voltage a described winding is connected to input voltage source.In addition, described primary circuit further comprises a pair of main switch and a pair of auxiliary switch, wherein, a pair of main switch comprises first main switch and second main switch, the drain electrode of described first main switch and source electrode are connected respectively to the first terminal of an input voltage source and a described winding, the grid of described first main switch receives described first switching signal, and the drain electrode of described second main switch and source electrode are connected respectively to second terminal and the earth terminal of a described winding, the grid of described second main switch receives described first switching signal, wherein, a pair of auxiliary switch comprises first auxiliary switch and second auxiliary switch, the drain electrode of described first auxiliary switch and source electrode are connected respectively between the described two-terminal of a described input voltage source and a described winding, the grid of described first auxiliary switch receives described second switching signal, and the drain electrode of described second auxiliary switch and source electrode be connected respectively to the described the first terminal and the described earth terminal of a described winding, and the grid of described second auxiliary switch receives described second switching signal.
Described soft switch power converter further comprises: first resistor, and it is coupled to described controller to adjust the pulse duration of second switching signal; Second resistor, it is coupled to described controller is defined as the load of described power converter with the pulse duration with described second switching signal function; And the 3rd resistor, it is coupled to described controller to adjust the switching frequency of described power converter.
The present invention also provides a kind of power converter, and it comprises: transformer, and it has winding and secondary winding; Primary circuit, it is coupled to a described winding, described primary circuit further comprises: first main switch, and the drain electrode of described first main switch and source electrode are connected respectively to the first terminal of an input voltage source and a described winding, and the grid of described first main switch receives first switching signal; Second main switch, the drain electrode of described second main switch and source electrode are connected respectively to second terminal and the earth terminal of a described winding, and the grid of described second main switch receives described first switching signal; First auxiliary switch, the drain electrode of described first auxiliary switch and source electrode are connected respectively between described second terminal of a described input voltage source and a described winding, and the grid of described first auxiliary switch receives second switching signal; And second auxiliary switch, the source electrode of described second auxiliary switch and drain electrode are connected respectively to the described the first terminal and the described earth terminal of a described winding, and the grid of described second auxiliary switch receives described second switching signal; Controller, it is operated to produce described first and second switching signals; Detect diode, between the detection input of its described second terminal that is connected in a described winding and described controller, in order to the detection Zero voltage transition; Feedback circuit, it is operated to produce feedback voltage in response to the output voltage of described power converter to described controller; And secondary circuit, it is connected between the output of described secondary winding and described power converter, and wherein said secondary circuit further comprises: half bridge rectifier, it is coupled to described secondary winding; Inductor, first end of described inductor is coupled to described half bridge rectifier; And capacitor, it is coupled to second end of described inductor.
Described controller can be operated to produce first and second switching signals, makes each switching circulation of described power converter comprise four operational phases.In first operational phase, described controller comes a described input voltage source of conducting and a described winding by producing described first switching signal via described first and second main switches.In second operational phase, described controller cuts off described first switching signal.In the 3rd operational phase, described controller produces second switching signal via described first and second auxiliary switches described input voltage source is connected to a described winding.In the 4th operational phase, described second switching signal is cut off.
The present invention further provides a kind of controller, it comprise oscillator, inverter, first to second comparator, first to the 3rd D flip-flop and first and door (AND gate) and second and.Described oscillator can be operated with clocking, ramp signal and serrated signal.Described inverter has input terminal and the lead-out terminal that receives described clock signal.Described first comparator has plus end, the negative terminal that is coupled to described ramp signal and the lead-out terminal that is connected to the feedback voltage that obtains from the output voltage of described power converter.Described second comparator has the plus end that is coupled to variable current, the negative terminal that is coupled to described serrated signal and lead-out terminal.The variable current sequential resistor of flowing through forms variable voltage, and described variable voltage and described serrated signal compare the signal that is used to produce described second switching signal with generation.Described first D flip-flop is coupled to the described lead-out terminal and the voltage source of described inverter and described first comparator.Described first D flip-flop further comprises output.Described second D flip-flop is coupled to the described lead-out terminal and the described voltage source of described inverter and described second comparator, and described second D flip-flop further comprises output.Described the 3rd D flip-flop is coupled to the described lead-out terminal of described inverter, and described the 3rd D flip-flop has first output and second output anti-phase with described first output.The described first output output of described the 3rd D flip-flop is used for first of described first switching signal and enables signal (enablesignal).The described second output output of described the 3rd D flip-flop is used for second of described second switching signal and enables signal.Signal is enabled in the described first described output and described first of being coupled to described first D flip-flop and described inverter with door.Signal is enabled in the described second described output and described second of being coupled to described second D flip-flop and described inverter with door.Described first produces first switching signal driving described first and second main switches with door, and described second produces described second switching signal to drive described first and second auxiliary switches with door.
Described controller comprises that further variable current source is to produce described variable current.Described variable current source comprises that programmable current source, electric current change voltage (I/V) resistor, operational amplifier, constant current source, a pair of mirrored transistor and the first transistor.The described programmable current of described I/V resistor of flowing through produces the voltage of the positive input terminal that is connected to described operational amplifier.The output of described operational amplifier is coupled in the grid of described the first transistor, the positive input terminal of described operational amplifier receives described first voltage, and the negative input end of described operational amplifier is coupled to the source electrode of described the first transistor, thereby produces described variable current by second resistor and described mirrored transistor.Described mirrored transistor is connected to described constant current source.Described the first transistor is coupled to one in the described mirrored transistor.Another mirrored transistor is exported described variable current.
Described oscillator comprises that reference voltage, mirrored transistor, transistor seconds and operational amplifier are to produce reference current by described reference resistor.Described operational amplifier produces reference current via the 3rd resistor, the output of wherein said operational amplifier is coupled to the grid of described transistor seconds, the negative input end of described operational amplifier is coupled to the source electrode of described transistor seconds, and the positive input terminal of described operational amplifier receives reference voltage.Described transistor seconds is coupled to one in the described mirrored transistor.
Described oscillator further comprises three mirrored transistor, the 3rd transistor, first and second operational amplifiers, resistor and from the constant current source of described reference current mirror.Three mirrored transistor are connected to described constant current source.Described the 3rd transistors couple is to described first mirrored transistor.The positive input terminal of described first operational amplifier receives described feedback voltage, and the output of described first operational amplifier is coupled to the described the 3rd transistorized grid, and the negative input end of described first operational amplifier is coupled to the described the 3rd transistorized source electrode.First end of described resistor is coupled to the described the 3rd transistorized source electrode, and second end of described resistor is coupled to the output of described second operational amplifier.The positive input terminal receive threshold voltage of described second operational amplifier, and the negative input end of described second operational amplifier is coupled to the output of described operational amplifier.Described second mirrored transistor is exported described programmable current.Described the 3rd mirrored transistor is exported discharging current able to programme.Difference between the geometric proportion of described programmable current and described discharging current able to programme and described mirrored transistor and described feedback voltage and the described threshold voltage is proportional, and is inversely proportional to the resistance of described resistor.Owing to the minimizing of described feedback voltage in response to the output loading of described power converter reduces, therefore described programmable current and described discharging current able to programme reduce under underload and no-load condition.
Described oscillator further comprises: first capacitor, it is operated to determine the switching frequency of described oscillator, wherein charging current and described first capacitor are used to produce the maximum opening time of described ramp signal and definite described first switching signal, and described charging current is from the reference current mirror; First pair of mirrored transistor and second pair of mirrored transistor; And first disable transistor and second disable transistor; Wherein, discharging current is flowed through described second pair of mirrored transistor so that described first capacitor is discharged, described discharging current is from described reference current mirror, and wherein said discharging current is via described second disable transistor, and described second disable transistor is enabled by second discharge signal; Wherein said discharging current and described first capacitor are used for determining the shut-in time of described second switching signal; Discharging current able to programme is flowed through described first pair of mirrored transistor so that described first capacitor is discharged, and wherein said discharging current able to programme is via described first disable transistor, and described first disable transistor is enabled by first discharge signal; Wherein said discharging current able to programme and described first capacitor are used for determining the shut-in time of described first switching signal; The minimizing according to load under light-load conditions of described discharging current able to programme reduces, therefore the corresponding increase of described shut-in time of described first switching signal; The described shut-in time of described second switching signal remains constant simultaneously, and it keeps short delaing time so that next realizes Zero voltage transition before switching circulation in beginning; In addition, when the described shut-in time of described first switching signal increased, the switching frequency of switching signal reduced.
Described oscillator further comprises: three comparators, and wherein the positive input terminal of the negative input end of first comparator and second comparator is connected to first end of first capacitor, and second end of described first capacitor is coupled to earth terminal; For determining switching frequency and described ramp signal, the positive input terminal of described first comparator and negative input end of described second comparator are connected respectively to high threshold voltage and low threshold voltage; Four NAND gate, wherein first and second NAND gate form the S-R latch cicuit; The input of described first and second NAND gate is connected respectively to the output of described first and second comparators; The output of described first NAND gate is connected to the input of third and fourth NAND gate, and the described input of the described output of described first NAND gate and described third and fourth NAND gate all receives described clock signal; Wherein enable signal and be applied to described third and fourth NAND gate, be used for first discharge signal and second discharge signal of the shut-in time control of described first and second switching signals with generation first and second; NOR gate; Transistor; Current source, it is used to draw high voltage; Switch; And capacitor;
Wherein apply described clock signal to open described switch, described switch and release current and described capacitor are used to produce described serrated signal, and described release current is from the reference current mirror; The positive input terminal of the 3rd comparator is connected to described current source and is used to detect the detection diode of Zero voltage transition; Negative input end of wherein said the 3rd comparator is coupled to threshold voltage; In case described the 3rd comparator detects low signal, so during the cycle of described second switching signal, described transistor will be opened by described NOR gate, with to the described first capacitor repid discharge and in time begin described next switch circulation.
Advantageously, described zero voltage switching pwm power transducer of the present invention is operated under constant high-frequency with low handoff loss, low stress and low noise.Described zero voltage switching pwm power transducer can be realized Zero voltage transition and handover operation, and need not to use the electric leakage inductor of extra magnetic machine or described transformer.It consumes relatively low power under underload and zero load condition.
Description of drawings
Providing, and incorporate in this specification and constitute the part of this specification in accompanying drawing is included in further understanding of the present invention.Description of drawings embodiments of the invention, and be used for explaining principle of the present invention with describing.In the accompanying drawings,
Fig. 1 is the circuit diagram according to soft switch power converter of the present invention.
Fig. 2 illustrate at as shown in fig. 1 soft switch power converter each switch the waveform of different operating in the stage of circulation.
The electric current that Fig. 3 a illustrates in first operational phase of switching circulation soft switch power converter as shown in fig. 1 flows.
The electric current that Fig. 3 b illustrates in second operational phase of switching circulation soft switch power converter as shown in fig. 1 flows.
The electric current that Fig. 3 c illustrates in the 3rd operational phase of switching circulation soft switch power converter as shown in fig. 1 flows.
The electric current that Fig. 3 d illustrates in the 4th operational phase of switching circulation soft switch power converter as shown in fig. 1 flows.
Fig. 4 is the circuit diagram of the controller of soft switch power converter as shown in fig. 1.
Fig. 5 and Fig. 6 illustrate and produce programmable clock signal with the pulse-width modulation frequency of control soft switch power converter as shown in fig. 1 and the circuit of operating in soft handover.
Fig. 7 illustrates the circuit that is used to produce variable current, and it determines to be applied to the pulse duration of switching signal of the auxiliary switch of soft switch power converter as shown in fig. 1.
Fig. 8 illustrates the waveform as clock signal and control signal illustrated in fig. 4.
Fig. 9 illustrates the shut-in time that is applied to the switching signal of main switch as the function of load.
Figure 10 illustrates the switching signal that is applied to auxiliary switch as the function of load.
Embodiment
Fig. 1 illustrates the circuit diagram of soft switch power converter provided by the present invention.As shown in fig. 1, soft switch power converter comprises transformer 50, a pair of main switch 10 and 20, a pair of auxiliary switch 30 and 40 and secondary circuit 150.Transformer 50 further comprises a winding Wp who is coupled to main switch and auxiliary switch 10,20,30 and 40, and secondary winding Ws then is coupled to secondary circuit.More particularly, in this embodiment, main switch 10 is connected to input voltage source V with winding Wp from the node A of the end of a winding Wp
IN, and node A further is connected to auxiliary switch 40.Auxiliary switch 30 is with input voltage source V
INBe connected to winding Wp one time from the Node B of the other end of a winding Wp, and main switch 20 further is connected to winding Wp one time from Node B.Main switch and auxiliary switch 10,20,30 and 40 can be including (for example) mos field effect transistor (metal-oxidesemiconductor field effect transistors, MOSFET), insulated gate bipolar transistor (insulated gate bipolar transistors, IGBT) and door turn-off transistor (gate-tum-off transistors, GTO).As shown in fig. 1, input voltage source V
INFurther be connected to capacitor 5.
As shown in fig. 1, main switch 10 and 20 is by switching signal S
1Drive, and auxiliary switch 30 and 40 is by switching signal S
2Drive.Referring to Fig. 2, switching signal S
1Be preferably and have pulse width T
1Pulse signal, and switching signal S
2Be preferably and have pulse width T
3Pulse signal.Soft switch power converter further comprises: controller 100, it is used to produce switching signal S
1And S
2And feedback circuit 300, it is coupled to the lead-out terminal of secondary circuit, with the output voltage V in response to power converter
0And with feedback voltage V
FBBe fed to controller 100.
As shown in fig. 1, controller 100 is connected to resistor 315,415,515, feedback voltage V
FB, main switch 10,20, auxiliary switch 30,40 and have the Node B of being coupled in and main switch 20 between the diode 105 of negative terminal.Resistor 315 can be through adjusting to be identified for driving the switching signal S of auxiliary switch 30 and 40
2Pulse width T
3Feedback voltage V
FBExcursion determine according to the voltage on the resistor 415, make switching signal S
2Pulse T
3Can be through the further function of adjusting as the load of the lead-out terminal that is connected to secondary circuit 150, the output voltage V of power converter
0From described lead-out terminal output.The switching frequency of power converter can be determined by the resistance of adjusting resistor 515.To further describe the detailed description of the various assemblies of controller 100 in this specification after a while.
By the open/close state of control main switch and auxiliary switch 10 to 40, power converter as shown in fig. 1 switches in the circulation at each and has four operational phases, as Fig. 2 and Fig. 3 a to as shown in the 3d.In addition, be operand power transducer in four operational phases of each circulation, switching signal S
1And S
2Must be out-phase.For example, in the embodiment as shown in Fig. 1 and Fig. 2, as switching signal S
1Switch the T of circulation at each
1 Main switch 10 and 20 conductings when being high during this time.In duration T
1During this time, auxiliary switch 30 and 40 cuts off.As switching signal S
1At a period of time (that is T as shown in Figure 2,
2) after the internal cutting off, auxiliary switch 30 and 40 is at a period of time T
3Interior conducting.
It is as follows to further describe described four operational phases referring to Fig. 2 and 3a to 3d.As shown in Figure 2, when each switched the circulation beginning, main switch 10 and 20 was at switching signal S
1Pulse width T
1The interior connection.As shown in Fig. 3 a, when main switch 10 and 20 activates, from input voltage V
INElectric current I
1Via main switch 10 and 20 and the winding Wp that flows through a time.Therefore, energy is delivered to secondary circuit from primary circuit.Simultaneously, winding Wp and secondary winding W
SPolarity make its conducting by forward bias being fed to rectifier diode 60, and free-wheel diode 70 is owing to cutting off to its reverse biased of supplying.Therefore, secondary current I
2Flow along secondary circuit, indicated as the arrow in the secondary circuit.Therefore energy delivery is to lead-out terminal and with output voltage V
0Output.
At T
1After, switching signal S
1Drop to zero or more low-voltage in second operational phase as shown in Figure 2, to cut off main switch 10 and 20.Referring to Fig. 3 b, primary current I
1Cut off.Yet, at auxiliary switch 30 and 40 by switching signal S
2Before the connection, electric current I
3Be caused with in second operational phase shown in Fig. 3 b, flow to input voltage source from a winding Wp via the parasitic diode of auxiliary switch 30 and 40.Therefore, secondary winding W
SIn rectifier diode 60 be reversed bias voltage and cut off, diode 70 is by forward bias and conducting, and the formation of the closed loop between inductor 80 and the capacitor 90.Therefore, secondary winding W
SBecome open circuit, and be stored in energy in the transformer 50 and be reset and get back to input voltage source V via the parasitic diode flywheel of auxiliary switch 30 and 40
INSimultaneously, be stored in the lead-out terminal that energy in inductor 80 and the capacitor 90 is delivered to secondary circuit continuously, and electric current I
4Produce and in closed loop circulation, as indicated by the arrow in the secondary circuit in Fig. 3 b.In addition, as shown in Figure 2, the duration T of second operational phase
2All energy that can be extended in being stored in transformer 50 are released.The variable duration of second operational phase is designated as T in Fig. 2
R
Fig. 2 and 3c illustrate the 3rd operational phase in each switching circulation of soft switch power converter.As shown in Figure 2, before next switches circulation in beginning, promptly at main switch 10 and 20 once more by switching signal S
1Before the connection, switching signal S
2Connect auxiliary switch 30 and 40.As shown in Fig. 3 c, electric current I
5Flowing to node A via a winding Wp from Node B, and energy is stored in the transformer 50 through guiding.In primary circuit, electric current I
5Along with second operational phase in the electric current I that produces
3Opposite direction flows.For secondary circuit, similarly be electric current I with second operational phase
5Direction cause the reverse biased of rectifier diode 60, make secondary winding W
SBecome open circuit.Therefore, transformer 50 was operated as inductor in this operational phase.Secondary winding W
SFor open circuit and there is not electric current to flow through, thus can realize the zero current of auxiliary switch 30 and 40 switch (zero-currentswitching, ZCS) or zero voltage switching (zero-voltage switching, ZVS).Therefore, soft switch power converter is similar in the case discontinuous mode and returns the power converter of speeding (flyback power converter) and operate.Therefore, the energy that is stored in the 3rd operational phase in the transformer 50 can be expressed as:
ε＝Lp×Ip
2/2，
Wherein Lp is the inductance of a winding Wp, and Ip be flow through a winding Wp electric current and can be expressed as:
IP＝V
IN×T
3/Lp，
T wherein
3Be the opening time of auxiliary switch 30 and 40.In equation with the equation substitution energy ε of Ip,
ε＝V
IN 2×T
3 2/(2×Lp).
In the 4th operational phase as shown in Fig. 2 and Fig. 3 d, switching signal S
2Drop to zero or low-voltage to cut off auxiliary switch 30 and 40, switching signal S simultaneously
1Keep low or be zero, thereby keep main switch 10 and 20 to cut off.Electric current I
5Therefore cut off from a winding Wp.Simultaneously, in the period T of the 3rd operational phase
3Middle generation also makes transformer 50 magnetized energy return the input voltage source V that speeds via the parasitic diode of main switch 10 and 20
INTherefore, be created in and result from electric current I in first operational phase
1The electric current I that flows on the opposite direction
7This realizes Zero voltage transition.
For in this operational phase, producing the electric current I of flow through main switch 10 and 20
7And the realization Zero voltage transition, main switch 10 and 20 parasitic diode must be connected.And, for connecting the parasitic diode of main switch 10 and 20, at first must be to its capacitor parasitics discharge.Therefore, for realizing Zero voltage transition, must satisfy with lower inequality:
V
IN 2×T
3 2/(2×Lp)＞2×(Cr×V
IN 2/2)
Wherein Cr is the parasitic capacitance of main switch 10 and 20.Resonance frequency fr between the capacitor parasitics of winding Wp and main switch 10 and 20 can be expressed as:
fr＝1/(2π×(Lp×Cr)
1/2)，
Realize minimum transfer time of the T of the phase shift of Zero voltage transition
FFor
T
F＝1/(4×fr)＝π×(Lp×Cr)
1/2/2
That is to say, from switching signal S
2Reduce to hang down and arrive main switch 10 and 20 once more by switching signal S to cut off auxiliary switch 30 and 40
1Minimum time during connection, promptly the minimum duration of quadravalence section can be used T
FAbove equation calculate.From above equation, the required minimum time of known realization Zero voltage transition is determined by inductance and the parasitic capacitance Cr of a winding Wp.
The duration of the 4th operational phase can be after the parasitic diode conducting of main switch 10 and 20 and postpone before next switches circulation in beginning one time of delay Tz.Therefore, the total duration of the 4th operational phase is minimum T transfer time
FWith time of delay Tz's and, i.e. T
4=T
F+ Tz.Yet, under the condition of Zero voltage transition in continuous mode operating induction device 80, in the duration T of the 3rd operational phase
3In the energy that is stored in the transformer 50 must satisfy with lower inequality:
V
IN 2×T
3 2/(2×Lp)＞{[Cr×V
IN 2]+[V
IN×(Ns/Np)×I
O×T
Z]+[T
Z×V
IN 2×T
3/Lp]}，
N wherein
SBe respectively secondary winding W with Np
SWith the number of turn of a winding Wp, and I
0Output current for power converter.That is to say, in duration T
3In be stored in energy in the transformer 50 must be enough greatly with to parasitic capacitance 2Cr discharge, and the reverse flywheel electric current of primary side then is provided and keeps output current during the Tz in time of delay.
In addition, be the optimization operating in soft handover, time of delay, Tz must minimize to save energy.In case controller 100 detects Zero voltage transition via diode 105 in the 4th operational phase, main switch 10 and 20 instantaneous so by switching signal S
1Connect.Therefore, but minimum latency time T z and optimization operating in soft handover.
Fig. 4 illustrates and is used to produce switching signal S
1And S
2The circuit diagram of controller 100.As shown in Figure 4, controller 100 comprise oscillator 200, inverter 370, comparator 320 and 330, variable current source 310, D flip-flop 340,350 and 360 and with door 380 and 390.Oscillator 200 is coupled to the input, comparator 320 of inverter 370 and 330 negative input.The output of inverter 370 be coupled to D flip-flop 340,350,360 and with the input of door 380 and 390.D flip-flop 340 further is coupled to the output of voltage source Vcc and comparator 320, and its output is coupled to and door 380.Enable signal S by D flip-flop 350 output
AAnd S
BReverse each other and respectively in feed-in and the door 380 and 390.D flip-flop 360 further is coupled to the output and the voltage source V of comparator 330
CC, and the output of D flip-flop 360 is coupled to and the input of door 390.Switching signal S
1And S
2From exporting to drive main switch 10,2 and auxiliary switch 30,40 respectively with door 380 and 390.
As shown in Figure 4, D flip-flop 350 will be enabled signal S
AAnd S
BBe provided to respectively and door 380 and 390, driving under the phase place separately to guarantee as shown in fig. 1 main switch 10,20 and auxiliary switch 30 and 40, and be slightly less than 50% of maximal duty cycle.Oscillator 200 can be operated with clocking 210, ramp signal 220 and serrated signal 230.Clock signal 210 is determined the pulse width modulation switching frequency of power converter, and switching signal S is provided
1With S
2Pulse between shut-in time (dead time), to realize the phase shift of Zero voltage transition.The output voltage V that in comparator 320, will reflect power converter
0Feedback voltage V
FBCompare with ramp signal 220.Work as feedback voltage V
FBWhen high, switching signal S
1Pulse width T
1Broaden, and more power is transferred to the output of power converter.Therefore, be derived from output voltage V
0Feedback voltage V
FBCan be used for regulating output voltage V
0In comparator 320 with feedback voltage V
FBCompare with the ramp signal 220 that produces by oscillator 200.Synchronous by the serrated signal 230 that oscillator 200 produces with ramp signal 220, and the amplitude of serrated signal 230 amplitudes and ramp signal 220 is inversely proportional to.Variable current source 310 produces as feedback voltage V
FBThe variable current Im of the resistor 315 of flowing through of function, thereby on resistor 315, produce variable voltage.In comparator 330, serrated signal 230 and the variable voltage that is produced by variable current source 310 are compared.By adjusting variable current Im, the variable voltage on the resistor 315 is able to programme, makes switching signal S
2Pulse width T
3Can be programmed or adjust.When feedback voltage increases according to the increase of load, variable current Im will raise and switching signal S
2Pulse width T
3To broaden, as shown in Figure 10.
Variable current source 310 shown in Fig. 7 comprises programmable current source 420, resistor 425, operational amplifier 410, current source 490, a pair of mirrored transistor 460,480 and transistor 450.Programmable current source 420 is flowed through resistor 425 and is produced the voltage of the positive input terminal be connected to operational amplifier 410.Negative input end of operational amplifier 410 is connected to transistor 450 and programming resistors device 415, produces electric current with the voltage according to resistor 425, and wherein programming resistors device 415 is with switching signal S
2Pulse width T
3Be defined as the function of the load of power converter.Described mirrored transistor 460,470 is connected to current source 490.Transistor 450 is coupled to mirrored transistor 460.Mirrored transistor 470 output variable current Im.
Referring to Fig. 5, oscillator 200 comprises reference voltage V
1, transistor 551, transistor 553 and operational amplifier 510 to be to produce reference current by resistor 515.Operational amplifier 510 is coupled in reference voltage V
1, between transistor 553 and the resistor 515.Transistor 553 is coupled to transistor 551 to produce reference current.Oscillator further comprises three mirrored transistor 561,562,563, transistor 560, two operational amplifiers 520 and 521, resistor 540 and by the current source of transistor 557 from the reference current mirror.Transistor 561,562,563 is connected to transistor 557.Transistor 560 is coupled to transistor 561.The plus end of operational amplifier 520 is coupled to feedback voltage V
FB, and the negative terminal of operational amplifier 520 is coupled to transistor 560.Resistor 540 is coupled to transistor 560 and operational amplifier 520.The plus end that operational amplifier 521 is coupled to resistor 540 and operational amplifier 521 is coupled to threshold voltage V
THTransistor 562 is from transistor 561 mirror programmable currents 420.Transistor 563 is from transistor 561 mirrors discharging current able to programme.Programmable current 420 and mirror ratio and the feedback voltage V of discharge programmable current with mirrored transistor 561,562,563
FBWith threshold voltage V
THBetween difference proportional, and be inversely proportional to the resistance of resistor 540.Because feedback voltage V
FBReduce in response to the minimizing of the output loading of power converter, therefore programmable current 420 and discharging current able to programme reduce under underload and no-load condition.
Oscillator 200 further comprises can be operated to determine the capacitor 530 of frequency of operation.Be associated with capacitor 530 from the charging current Ic of reference current mirror, and be used to produce ramp signal 220 and determine the first switching signal S
1The maximum opening time.Oscillator 200 further comprises 564,565 and second pairs of mirrored transistor of first mirrored transistor 574,575, first disable transistor 568 and second disable transistor 578, in order to control discharging current I
DBy transistor 559 from the discharging current of the reference current mirror second pair of mirrored transistor 574,575 of flowing through, with to capacitor 530 discharges.Discharging current I
DEnable by the second discharge signal WB via second disable transistor 578.Discharging current I
DBe associated to determine the second switching signal S with capacitor 530
2Shut-in time T
OFFFlow through first pair of mirrored transistor 564,565 so that capacitor 530 is discharged from the discharging current able to programme of transistor 563 mirrors.Discharging current able to programme is enabled by the first discharge signal WA via first disable transistor 568.Discharging current able to programme is associated with capacitor 530 to determine the first switching signal S
1Shut-in time T
OFFBecause discharging current able to programme minimizing according to load under light-load conditions reduces, so the first switching signal S
1Shut-in time T
OFFTherefore increase, as shown in Figure 9.The while second switching signal S
2Shut-in time T
OFFRemain constant, it is kept than short delaing time T
4So that next realizes Zero voltage transition before switching circulation in beginning, as shown in Figure 8.Therefore, the first switching signal S
1Shut-in time T
OFFIncrease, the switching frequency of switching signal reduces, and therefore the handoff loss and the power consumption of power converter reduce under underload and no-load condition.
The switching frequency Freq of oscillator is the inverse in cycle, is expressed as:
Freq＝1/T＝1/(2×T
ON＋T
OFF＋T
4)，
Wherein switch in the circulation at each, transformer 50 is conducting to input voltage source V
INTwice, once via main switch 10 and 20, and, make each period T comprise two opening times once via auxiliary switch 30 and 40, it is expressed as 2 * T
ON(T
1And T
3).In addition, main switch and auxiliary switch 10 to 40 also switch twice in each cycle, that is, and and by T
OFFShut-in time of expression and another shut-in time T
4
Opening time, shut-in time and T
4Can derive from the voltage on electric capacity 530 (" Cc "), the capacitor 530 landing and its electric current of flowing through, as follows;
T
ON＝Cc×(V
H-V
L)/I
C
Wherein Ic is the charging current of capacitor 530;
T
OFF＝Cc×(V
H-V
L)/Id-A
Wherein Id-A under the control of signal WA from the discharging current of the capacitors 530 of flowing through of transistor 564,565 and 568 supplies;
T
4＝Cc×(V
H-V
L)/Id-B
Wherein Id-B is the duration T in the 4th operational phase
4In, under the control of signal WB from the discharging current of capacitors 530 of transistor 574,575 and 578 supplies.
In addition, charging current Ic and discharging current Id-A and Id-B can be expressed as:
Ic＝(V
1/R
515)×K1，
V wherein
1Be reference voltage, and K1=N
558/ N
551, it is the geometric proportion of transistor 558 and transistor 551;
Id-A＝[(V
FB-V
TH)/R
540]×K2
(V wherein
FB-V
TH) be the voltage landing on the resistor 540, and K2=(N
563/ N
561) * (N
565/ N
564), its geometry by transistor 563,561 and transistor 565,564 is recently determined; With
Id-B＝(V
1/R
515)×K3
K3=(N wherein
559/ N
551) * (N
575/ N
574), it is the product of the geometric proportion of transistor 559,551 and transistor 575,574.
Oscillator 200 further comprises 710,720,730, four NAND gate 740,750,770,780 of three comparators, NOR gate 790, transistor 725, current source 715, switch 625, capacitor 540 and by the release current 620 of reference current mirror.Negative input end of comparator 710 and the positive input terminal of comparator 720 are connected to capacitor 530.For determining switching frequency and ramp signal 220, the positive input terminal of comparator 710 and negative input end of comparator 720 are connected respectively to high threshold voltage V
HWith low threshold voltage V
LNAND gate 740,750 forms the S-R latch cicuit.NAND gate 740 and 750 input are connected respectively to the output of comparator 710 and 720.NAND gate 740 outputs are connected to the clock signal 210 of the input of NAND gate 770 and 780.Enable signal Sa and SB is applied to NAND gate 770 and 780 respectively with first and second, be used for the first and second switching signal S with generation
1And S
2The first discharge signal WA and the second discharge signal WB of shut-in time control.Also apply clock signal 210 to open switch 625, described switch 625 is associated with release current 620 and capacitor 540 to produce serrated signal 230 as shown in Figure 8.Therefore, serrated signal 230 is used for comparing with generation with variable voltage and is used for the second switching signal S
2Signal.The positive input terminal of comparator 730 is connected to current source 715 and is used to detect the detection diode 105 of Zero voltage transition.Current source 715 is used to draw high.Negative input end of comparator 730 is coupled to threshold voltage V
2In case low signal is detected by comparator 730, so at the second switching signal S
2Cycle during, transistor 725 will be opened with to capacitor 530 repid discharges by NOR gate 790, switch circulation so that in time begin next.Therefore realize zero voltage switching and improve the efficient of power converter.
As shown in Figure 9, in response to feedback voltage V
FBMinimizing, close the duration T of main switch 10,20
OFFWith slope K
xAnd increase, up to reaching minimum value T
MinIt can be expressed as
T
OFF＝k
x÷(|V
FB-V
TH|)
T wherein
OFF＞T
Min＞0.
On the contrary, as shown in Figure 10, connect the duration of auxiliary switch 30,40, i.e. its pulse width T
3With slope q
xAnd increase, up to reaching maximum of T
MaxThe resistance of resistor 315,415 is determined slope q
xIt can be expressed as
T
3＝q
x×(V
FB-V
TH)
q
x＝(R
315/R
415)×K5
Wherein K5 is a constant.
In the circuit that is proposed, main switch and auxiliary switch are operated by ZVS and ZCS respectively.Compare with the prior art of soft switch, do not need the leakage inductance of extra magnetic machine or transformer.Therefore, handoff loss, stress and noise reduce.In addition, because the switching frequency minimizing, so the power consumption of power converter reduces extraly under light-load conditions.
The those skilled in the art will easily understand, can do not depart from the scope of the present invention or the situation of spirit under, structure of the present invention is carried out various modifications and variations.In view of mentioned above, wish that the present invention is encompassed in the modifications and variations of the present invention in appended claims and its equivalent scope.
Claims (13)
1. soft switch power converter, it comprises:
Transformer, it has winding and secondary winding;
Primary circuit, it is coupled to a described winding, and wherein said primary circuit further comprises a pair of main switch and a pair of auxiliary switch,
Secondary circuit, it is coupled to described secondary winding;
Feedback circuit, its output of being coupled to described secondary circuit is to produce feedback voltage; And
Controller, it is coupled to feedback circuit and described primary circuit, described controller is operated in response to described feedback voltage a described winding is connected to input voltage source, wherein said controller is operated to produce first switching signal and second switching signal of out-phase each other, thereby drive described main switch and described auxiliary switch respectively
Wherein, a pair of main switch comprises first main switch and second main switch, the drain electrode of described first main switch and source electrode are connected respectively to the first terminal of an input voltage source and a described winding, the grid of described first main switch receives described first switching signal, and the drain electrode of described second main switch and source electrode are connected respectively to second terminal and the earth terminal of a described winding, the grid of described second main switch receives described first switching signal
Wherein, a pair of auxiliary switch comprises first auxiliary switch and second auxiliary switch, the drain electrode of described first auxiliary switch and source electrode are connected respectively between the described two-terminal of a described input voltage source and a described winding, the grid of described first auxiliary switch receives described second switching signal, and the drain electrode of described second auxiliary switch and source electrode be connected respectively to the described the first terminal and the described earth terminal of a described winding, and the grid of described second auxiliary switch receives described second switching signal.
2. soft switch power converter according to claim 1, it further comprises:
Detect diode, between the detection input of its described second terminal that is connected in a described winding and described controller, in order to the detection Zero voltage transition.
3. soft switch power converter according to claim 1, it further comprises:
First resistor, it is coupled to described controller to adjust the pulse duration of described second switching signal;
Second resistor, it is coupled to described controller is defined as the load of described power converter with the pulse duration with described second switching signal function; And
The 3rd resistor, it is coupled to described controller to adjust the switching frequency of described power converter.
4. power converter, it comprises:
Transformer, it has winding and secondary winding;
Primary circuit, it is coupled to a described winding, described primary circuit further comprises: first main switch, and the drain electrode of described first main switch and source electrode are connected respectively to the first terminal of an input voltage source and a described winding, and the grid of described first main switch receives first switching signal; Second main switch, the drain electrode of described second main switch and source electrode are connected respectively to second terminal and the earth terminal of a described winding, and the grid of described second main switch receives described first switching signal; First auxiliary switch, the drain electrode of described first auxiliary switch and source electrode are connected respectively between described second terminal of a described input voltage source and a described winding, and the grid of described first auxiliary switch receives second switching signal; And second auxiliary switch, the drain electrode of described second auxiliary switch and source electrode are connected respectively to the described the first terminal and the described earth terminal of a described winding, and the grid of described second auxiliary switch receives described second switching signal;
Controller, it is operated to produce described first and second switching signals;
Detect diode, between the detection input of its described second terminal that is connected in a described winding and described controller, in order to the detection Zero voltage transition;
Feedback circuit, it is operated to produce feedback voltage in response to the output voltage of described power converter to described controller; And
Secondary circuit, it is connected between the output of described secondary winding and described power converter, and wherein said secondary circuit further comprises: half bridge rectifier, it is coupled to described secondary winding; Inductor, first end of described inductor is coupled to described half bridge rectifier; And capacitor, it is coupled to second end of described inductor.
5. power converter according to claim 4, wherein said power converter was operated in a plurality of operational phases, comprising:
In first operational phase, described controller is operated to produce described first switching signal, with via described first main switch and a described described input voltage source of the second main switch conducting and a described winding, wherein when described first switching signal produced, electric current was switched on and flows to from the described the first terminal of a described winding via described first and second main switches described second terminal of a described winding;
In second operational phase, described first switching signal is cut off so that described input voltage source is connected with described winding disconnection, wherein said first switching signal is cut off, and electric current is caused and flows to described input voltage source via described first and second auxiliary switches from a described winding;
In the 3rd operational phase, described second switching signal is produced via described first auxiliary switch and described second auxiliary switch described input voltage source is connected to a described winding, wherein said second switching signal is produced, and electric current is switched on and flows to from described second terminal of a described winding via described first and second auxiliary switches described the first terminal of a described winding; And
In the 4th operational phase, described second switching signal is cut off so that described input voltage source is connected with described winding disconnection, wherein when described second switching signal was cut off, electric current was caused and flows to described input voltage source via described first and second main switches from a described winding.
6. power converter according to claim 4, wherein said controller further comprises:
Oscillator, it is operated with clocking, ramp signal and serrated signal;
Inverter, it has input terminal and the lead-out terminal that receives described clock signal;
First comparator, it has the plus end that is connected to the feedback voltage that obtains from the output voltage of described power converter, the negative terminal that is coupled to described ramp signal, and lead-out terminal;
Second comparator, it has the plus end that is coupled to the variable current and first resistor, the negative terminal that is coupled to described serrated signal, and lead-out terminal;
Three D flip-flops, it is operated producing first output in response to described clock signal, the feedback voltage that produces in response to the output voltage of described power converter and described ramp signal, produces second output in response to described clock signal and described serrated signal and the variable voltage that produces in response to described variable current and described first resistor; And
Two and door, to export in response to described first output and described second and to produce described first and second switching signals respectively, the pulse duration of wherein said second switching signal is adjusted by described variable voltage through operation for it,
Wherein said three d type flip flops comprise: first D flip-flop, and it is coupled to the described lead-out terminal and the voltage source of described inverter and described first comparator, and described first D flip-flop further comprises output; Second D flip-flop, it is coupled to the described lead-out terminal and the described voltage source of described inverter and described second comparator, and described second D flip-flop further comprises output; And the 3rd D flip-flop, it is coupled to the described lead-out terminal of described inverter, and described the 3rd D flip-flop has first output and second output reverse with described first output,
Wherein said two comprise with door: first with door, it is coupled to first output of the described output of described first D flip-flop and described inverter and described the 3rd D flip-flop; And second and door, it is coupled to described second output of the described output of described second D flip-flop and described inverter and described the 3rd D flip-flop.
7. controller, it is applicable to and comprises the power converter that be connected of transformer with control input voltage source and described transformer that described controller comprises:
Oscillator, it is operated with clocking, ramp signal and serrated signal;
Inverter, it has input terminal and the lead-out terminal that receives described clock signal;
First comparator, it has the plus end that is connected to the feedback voltage that obtains from the output voltage of described power converter, the negative terminal that is coupled to described ramp signal, and lead-out terminal;
Second comparator, it has the plus end that is coupled to the variable current and first resistor, the negative terminal that is coupled to described serrated signal, and lead-out terminal;
First D flip-flop, it is coupled to the described lead-out terminal and the voltage source of described inverter and described first comparator, and described first D flip-flop further comprises output;
Second D flip-flop, it is coupled to the described lead-out terminal and the described voltage source of described inverter and described second comparator, and described second D flip-flop further comprises output;
The 3rd D flip-flop, it is coupled to the described lead-out terminal of described inverter, and described the 3rd D flip-flop has first output and second output reverse with described first output;
First with door, it is coupled to first output of the described output of described first D flip-flop and described inverter and described the 3rd D flip-flop; And
Second with door, it is coupled to described second output of the described output of described second D flip-flop and described inverter and described the 3rd D flip-flop,
Wherein said first is operated producing first switching signal driving first main switch and second main switch with door, and described second is operated to produce described second switching signal to drive first auxiliary switch and second auxiliary switch with door.
8. controller according to claim 7, it further comprises variable current source, in order to produce described variable current, wherein said variable current is adjusted in response to described feedback voltage.
9. controller according to claim 8, wherein said variable current source further comprises:
Electric current changes voltage resistor voltage;
Programmable current source, it changes voltage resistor voltage and produces first voltage via described electric current;
Constant current source;
A pair of mirrored transistor, it is connected to described constant current source;
The first transistor, it is coupled to one in the described mirrored transistor; And
Operational amplifier, the output of described operational amplifier is coupled in the grid of described the first transistor, the positive input terminal of described operational amplifier receives described first voltage, and the negative input end of described operational amplifier is coupled to the source electrode of described the first transistor, thereby produces described variable current by second resistor and described mirrored transistor.
10. controller according to claim 7, wherein said oscillator comprises:
Reference voltage;
Mirrored transistor;
Transistor seconds; And
Operational amplifier, it produces reference current via the 3rd resistor, the output of wherein said operational amplifier is coupled to the grid of described transistor seconds, the negative input end of described operational amplifier is coupled to the source electrode of described transistor seconds, the positive input terminal of described operational amplifier receives reference voltage, and described transistor seconds is coupled to one in the described mirrored transistor.
11. controller according to claim 7, wherein said oscillator further comprises:
Three mirrored transistor;
The 3rd transistor;
First and second operational amplifiers;
Resistor; And
Constant current source, it is from the reference current mirror, wherein said three mirrored transistor are connected to described constant current source, described the 3rd transistors couple in the described mirrored transistor first, the positive input terminal of described first operational amplifier receives described feedback voltage, the output of described first operational amplifier is coupled to the described the 3rd transistorized grid, the negative input end of described first operational amplifier is coupled to the described the 3rd transistorized source electrode, first end of described resistor is coupled to the described the 3rd transistorized source electrode, second end of described resistor is coupled to the output of described second operational amplifier, the positive input terminal receive threshold voltage of described second operational amplifier, and the negative input end of described second operational amplifier is coupled to the output of described operational amplifier, the two output programmable current in the described mirrored transistor, the third party in the described mirrored transistor exports discharging current able to programme, difference between the geometric proportion of described programmable current and described discharging current able to programme and described mirrored transistor and described feedback voltage and the described threshold voltage is proportional, and be inversely proportional to the resistance of described resistor, owing to the minimizing of described feedback voltage in response to the output loading of described power converter reduces, therefore described programmable current and described discharging current able to programme reduce under light-load conditions and no-load condition.
12. controller according to claim 7, wherein said oscillator further comprises:
First capacitor, it is operated to determine the switching frequency of described oscillator, and wherein charging current and described first capacitor are used to produce the maximum opening time of described ramp signal and definite described first switching signal, and described charging current is from the reference current mirror;
First pair of mirrored transistor and second pair of mirrored transistor; And
First disable transistor and second disable transistor;
Wherein, discharging current is flowed through described second pair of mirrored transistor so that described first capacitor is discharged, described discharging current is from described reference current mirror, and wherein said discharging current is via described second disable transistor, and described second disable transistor is enabled by second discharge signal; Wherein said discharging current and described first capacitor are used for determining the shut-in time of described second switching signal; Discharging current able to programme is flowed through described first pair of mirrored transistor so that described first capacitor is discharged, and wherein said discharging current able to programme is via described first disable transistor, and described first disable transistor is enabled by first discharge signal; Wherein said discharging current able to programme and described first capacitor are used for determining the shut-in time of described first switching signal; The minimizing according to load under light-load conditions of described discharging current able to programme reduces, therefore the corresponding increase of described shut-in time of described first switching signal; The described shut-in time of described second switching signal remains constant simultaneously, and it keeps short delaing time so that next realizes Zero voltage transition before switching circulation in beginning; In addition, when the described shut-in time of described first switching signal increased, the switching frequency of switching signal reduced.
13. controller according to claim 7, wherein said oscillator further comprises:
Three comparators, wherein the positive input terminal of the negative input end of first comparator and second comparator is connected to first end of first capacitor, and second end of described first capacitor is coupled to earth terminal; For determining switching frequency and described ramp signal, the positive input terminal of described first comparator and negative input end of described second comparator are connected respectively to high threshold voltage and low threshold voltage;
Four NAND gate, wherein first and second NAND gate form the S-R latch cicuit; The input of described first and second NAND gate is connected respectively to the output of described first and second comparators; The output of described first NAND gate is connected to the input of third and fourth NAND gate, and the described input of the described output of described first NAND gate and described third and fourth NAND gate all receives described clock signal; Wherein enable signal and be applied to described third and fourth NAND gate, be used for first discharge signal and second discharge signal of the shut-in time control of described first and second switching signals with generation first and second;
NOR gate;
Transistor;
Current source, it is used to draw high voltage;
Switch; And
Capacitor;
Wherein apply described clock signal to open described switch, described switch and release current and described capacitor are used to produce described serrated signal, and described release current is from the reference current mirror; The positive input terminal of the 3rd comparator is connected to described current source and is used to detect the detection diode of Zero voltage transition; Negative input end of wherein said the 3rd comparator is coupled to threshold voltage; In case described the 3rd comparator detects low signal, so during the cycle of described second switching signal, described transistor will be opened by described NOR gate, with to the described first capacitor repid discharge and in time begin described next switch circulation.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| PCT/CN2004/000362 WO2005101635A1 (en) | 2004-04-16 | 2004-04-16 | Soft-switching power converter having power saving means |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1938931A CN1938931A (en) | 2007-03-28 |
| CN1938931B true CN1938931B (en) | 2010-09-01 |
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ID=35150302
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2004800427529A Expired - Fee Related CN1938931B (en) | 2004-04-16 | 2004-04-16 | Soft switch power converter with power-saving member |
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|---|---|
| CN (1) | CN1938931B (en) |
| WO (1) | WO2005101635A1 (en) |
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| US11527950B2 (en) | 2019-03-25 | 2022-12-13 | Semiconductor Components Industries, Llc | Power supply system for controlling load distribution across multiple converters for optimizing overall efficiency |
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| CN113541501B (en) * | 2021-07-09 | 2023-02-10 | 无锡芯朋微电子股份有限公司 | Flyback switching power supply and control method and circuit for improving conversion efficiency of flyback switching power supply |
| TWI822091B (en) * | 2021-09-06 | 2023-11-11 | 立錡科技股份有限公司 | Half-bridge flyback power converter and control method thereof |
| CN114421781B (en) * | 2022-03-31 | 2022-07-15 | 深圳市芯茂微电子有限公司 | Control method of resonant converter |
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| US4672528A (en) * | 1986-05-27 | 1987-06-09 | General Electric Company | Resonant inverter with improved control |
| CN1109654A (en) * | 1994-12-29 | 1995-10-04 | 广东金泰企业集团公司 | Combined control inverse method of pulse width modulation and zero current zero voltage harmonic switch |
| US6016052A (en) * | 1998-04-03 | 2000-01-18 | Cts Corporation | Pulse frequency modulation drive circuit for piezoelectric transformer |
| CN1373553A (en) * | 2001-03-02 | 2002-10-09 | 深圳市中兴通讯股份有限公司 | High-reliability control circuit for full-bridge phase-shift zero-voltage zero-current switching power supply |
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| TWI778852B (en) * | 2021-04-08 | 2022-09-21 | 通嘉科技股份有限公司 | Control method of a flyback power converter |
Also Published As
| Publication number | Publication date |
|---|---|
| WO2005101635A1 (en) | 2005-10-27 |
| CN1938931A (en) | 2007-03-28 |
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