CN102064723B - Flyback converter system capable of avoiding simultaneous switching-on of switches on two sides - Google Patents

Flyback converter system capable of avoiding simultaneous switching-on of switches on two sides Download PDF

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Publication number
CN102064723B
CN102064723B CN 200910225278 CN200910225278A CN102064723B CN 102064723 B CN102064723 B CN 102064723B CN 200910225278 CN200910225278 CN 200910225278 CN 200910225278 A CN200910225278 A CN 200910225278A CN 102064723 B CN102064723 B CN 102064723B
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China
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switch
coupled
secondary side
module
output
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CN 200910225278
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Chinese (zh)
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CN102064723A (en
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陈富权
杜保宏
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沛亨半导体股份有限公司
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Publication of CN102064723A publication Critical patent/CN102064723A/en
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Abstract

The invention discloses a flyback converter system. The simultaneous switching-on of a primary side switch and a secondary side switch of the flyback converter system can be avoided by a controller. The controller comprises a switch switching-on module, a switch switching-off module and a switch enabling module, wherein the switch switching-on module is used for switching the secondary side switch on; the switch switching-off module controls the switching-off of the secondary side switch according to the impedance of a load and the period of the secondary side switch; and the switch enabling module is used for controlling the enabling or not of the secondary side switch according to the impedance of the load.

Description

The flyback commutation system that can avoid the both sides switch to open simultaneously

Technical field

The invention relates to a kind of flyback commutation system, espespecially a kind of flyback commutation system of avoiding the both sides switch to open simultaneously.

Background technology

Recently because the progress of electronic product is at a tremendous pace, product is increasingly compact, and function is diversification day by day thereupon also, and requires simultaneously power consumption not promote thereupon.Therefore, what become in the design of power management IC is more complicated, more efficient, requires higher power density ratio in unit are, and that high-frequency switched power supply is just meeting is required.

Flyback rectifier (flyback converter) is one of most widely used switched-mode power supply circuit, although flyback converter circuit itself need not done the electrical equipment isolation, but in fact for the consideration on power raising and safety, must consider isolation output and input.The flyback rectifier is one to have the falling-rising type rectifier (buck-boost converter) of isolation characteristic.The magnetic element function of flyback rectifier is not transformer, but utilizes coupling inductance to reach the purpose of power conversion.In addition, it is low that the flyback rectifier has a cost, and circuit design is ripe, and the characteristics such as framework is simple, so normal the use at the design of the accessory power supply power supply requirement with the supply whole system.

Please refer to Fig. 1, Fig. 1 is the schematic diagram that shows traditional flyback commutation system 10.Flyback commutation system 10 comprises an electric power supply module 101 and an electric energy receiver module 102.Electric power supply module 101 comprises primary side 1012, and the primary side switch 1013 of a stable-pressure device 1011, flyback commutation system 10.Stable-pressure device 1011 is in order to stablize the voltage of input power supply module 101, the primary side 1012 of flyback commutation system 10 is coupled to stable-pressure device 1011, primary side switch 1013 is coupled between the primary side 1012 of stable-pressure device 1011 and flyback commutation system 10, in order to the direction of the magnetic flux of the primary side 1012 of controlling flyback commutation system 10.Electric energy receiver module 102 comprises secondary side 1021, a secondary side switches 1022, a controller 1023, a load capacitance C of flyback commutation system 10 L, a load resistance R L, a filter capacitor C dc, a secondary side switches 1022 is in order to opening time adjusting resistance RMOT, an and filter resistance R dcThe electric energy that the secondary side 1021 of flyback commutation system 10 transmits in order to the primary side 1012 of responding to flyback commutation system 10, secondary side switches 1022 are coupled to the secondary side 1021 of flyback commutation system 10.Controller 1023 judges whether opening and closing secondary side switches 1022 according to the drain terminal voltage of secondary side switches 1022.

When primary side switch 1013 is opened, the primary side 1012 of flyback commutation system 10 gradually has electric current and flows through, and store energy in primary side 1012, relation due to the coil flux quantitative change, primary side 1012 and secondary side 1021 polarity are opposite, A in Fig. 1, B point is high potential, so the parasitic diode of secondary side switches 1022 is not had energy to be transferred to electric energy receiver module 102 by reverse bias; Otherwise, when primary side switch 1013 cuts out, because disappearing, the coil flux amount cause the B point to become electronegative potential, and this moment, the parasitic diode of secondary side switches 1022 was switched on, and energy is transferred to electric energy receiver module 102, load capacitance C LBe recharged load resistance R LThere is electric current to flow through.

Please refer to Fig. 2, Fig. 2 shows that working as electric energy receiver module 102 is in underload (discontinuouscurrent mode, DCM) time, the drain terminal voltage of secondary side switches 1022, the gate terminal driving voltage of secondary side switches 1022, and open the duration and close the duration oscillogram.When disappearing, the coil flux amount cause the B point to become electronegative potential and lower than switch open threshold value V TH2, secondary side switches 1022 is unlocked, and the gate terminal driving voltage becomes high potential from electronegative potential.Because be underload, so the electric current of the secondary side switches 1022 of flowing through is little, therefore when coil flux amount direction changed once again, the electric current of the secondary side switches of flowing through 1022 can be down to zero, and B point current potential rises and closes threshold value V over switch TH1The time, secondary side switches 1022 is closed, and the gate terminal driving voltage becomes electronegative potential from high potential.

Please refer to Fig. 3, Fig. 3 shows when electric energy receiver module 102 is in heavy duty (continuouscurrent mode, CCM), the drain terminal voltage of secondary side switches 1022, the gate terminal driving voltage of secondary side switches 1022, and open the duration oscillogram.When disappearing, the coil flux amount cause the B point to become electronegative potential and lower than switch open threshold value V TH2, the parasitic diode conducting of secondary side switches 1022 at this moment, secondary side switches 1022 is unlocked, and the gate terminal driving voltage becomes high potential from electronegative potential.Because be heavy duty, large under the current ratio DCM pattern of secondary side switches 1022 so flow through, so when coil flux amount direction changes once again, the electric current of the secondary side switches of flowing through 1022 can not be down to zero, still have cross-pressure to exist between the source electrode of secondary side switches 1022 and drain electrode, therefore need configuration switch close threshold value V TH1For closing threshold value V than the switch under DCM pattern TH1More negative value is closed threshold value V to avoid B point current potential to rise over switch TH1, make secondary side switches 1022 to close, allow primary side switch 1013 and secondary side switches 1022 simultaneously in opening, cause circuit burnout.

In summary, traditional flyback commutation system 10 has following two shortcomings.The first, if flyback commutation system 10 design operations in the DCM pattern, but enter the CCM pattern because suddenly load becomes the heavy flyback commutation system 10 that allows from DCM, B point current potential can't rise and closed threshold value V over switch this moment TH1(because V TH1(DCM) be greater than V TH1(CCM)), make secondary side switches 1022 to close, allow primary side switch 1013 and secondary side switches 1022 simultaneously in opening, cause circuit burnout.The second, if for fear of the security consideration of circuit burnout, go configuration switch to close threshold value V with the most heavy duty situation TH1, but secondary side switches 1022 can too early be closed and made flyback commutation system 10 efficient can't reach best when underload.

Summary of the invention

One embodiment of the invention provide a kind of flyback commutation system of avoiding the both sides switch to open simultaneously, and this system comprises electric power supply module and electric energy receiver module.This electric power supply module comprises primary side and the primary side switch of stable-pressure device, flyback commutation system.This stable-pressure device, voltage in order to stable this power supply module of input, the primary side of this flyback commutation system, be coupled to this stable-pressure device, this primary side switch, be coupled between the primary side of this stable-pressure device and this flyback commutation system, in order to the direction of the magnetic flux of the primary side of controlling this flyback commutation system.This electric energy receiver module comprises secondary side, secondary side switches, and the controller of this flyback commutation system.The electric energy that the secondary side of this flyback commutation system transmits in order to the primary side of responding to this flyback commutation system, this secondary side switches is coupled to the secondary side of this flyback commutation system.This controller comprises switch open module, switch closing module, reaches trigger.This switch open module, in order to open this secondary side switches, this switch closing module, in order to close this secondary side switches, this trigger, be coupled to this switch open module and be somebody's turn to do or door, in order to control the unlatching of this secondary side switches and to close according to the output signal of this switch open module and this switch closing module.This switch closing module comprises the first switch and closes closed submodule, second switch and close closed submodule, and or door.This first switch closes closed submodule, in order to control closing of this secondary side switches according to the size of impedance of a load that is coupled to this electric energy receiver module, this two switch closes closed submodule, in order to closing according to this secondary side switches of periodic Control of this secondary side switches, be somebody's turn to do or door, be coupled to this first switch pass closed submodule and this second switch and close closed submodule, the output signal of closing closed submodule in order to close closed submodule and this second switch according to this first switch is controlled this closing of side switch for the second time.

Another embodiment of the present invention provides a kind of controller of avoiding flyback commutation system both sides switch to open simultaneously, and this controller comprises a switch open module, a switch closing module, an and trigger.This switch open module, in order to open a secondary side switches, this switch closing module, in order to close a secondary side switches, this trigger, be coupled to this switch open module and be somebody's turn to do or door, in order to control the unlatching of this secondary side switches and to close according to the output signal of this switch open module and this switch closing module.This switch closing module comprises one first switch and closes closed submodule, a second switch and close closed submodule, and one or door.This first switch closes closed submodule, in order to control closing of this secondary side switches according to the size of impedance of a load that is coupled to an electric energy receiver module, this second switch closes closed submodule, in order to closing according to this secondary side switches of periodic Control of this secondary side switches, be somebody's turn to do or door, be coupled to this first switch pass closed submodule and this second switch and close closed submodule, the output signal of closing closed submodule in order to close closed submodule and this second switch according to this first switch is controlled closing of this secondary side switches.

Another embodiment of the present invention provides a kind of flyback commutation system of avoiding the both sides switch to open simultaneously, and this system comprises an electric power supply module and an electric energy receiver module.This electric power supply module comprises primary side, and the primary side switch of a stable-pressure device, a flyback commutation system.This stable-pressure device, voltage in order to stable this power supply module of input, the primary side of this flyback commutation system, be coupled to this stable-pressure device, and this primary side switch is coupled between the primary side of this stable-pressure device and this flyback commutation system, in order to the direction of the magnetic flux of the primary side of controlling this flyback commutation system.This electric energy receiver module comprises secondary side, a secondary side switches, and the controller of this flyback commutation system.The secondary side of this flyback commutation system, the electric energy that transmits in order to the primary side of responding to this flyback commutation system, this secondary side switches, be coupled to the secondary side of this flyback commutation system, this controller comprises a switch open module, a switch closing module, a trigger, reaches an activation switch module.This switch open module, in order to open this secondary side switches, this switch closing module, in order to control closing of this secondary side switches according to the size of impedance of a load that is coupled to this electric energy receiver module, this trigger, be coupled to this switch open module and be somebody's turn to do or door, in order to control the unlatching of this secondary side switches and to close according to the output signal of this switch open module and this switch closing module, this activation switch module is in order to control the whether activation of this secondary side switches according to the size of the impedance of this load.

Another embodiment of the present invention provides a kind of controller of avoiding flyback commutation system both sides switch to open simultaneously, and this controller comprises a switch open module, a switch closing module, a trigger, an and activation switch module.This switch open module, in order to open a secondary side switches, this switch closing module, in order to control closing of this secondary side switches according to the size of impedance of a load that is coupled to this electric energy receiver module, this trigger, be coupled to this switch open module and be somebody's turn to do or door, in order to control the unlatching of this secondary side switches and to close according to the output signal of this switch open module and this switch closing module, this activation switch module is in order to control the whether activation of this secondary side switches according to the size of the impedance of this load.

Description of drawings

Fig. 1 is the schematic diagram that shows traditional flyback commutation system.

Fig. 2 shows when the electric energy receiver module of Fig. 1 flyback commutation system is in underload, the gate terminal driving voltage of the drain terminal voltage of secondary side switches, secondary side switches and open the duration and the duration of closing oscillogram.

Fig. 3 shows when the electric energy receiver module of Fig. 1 flyback commutation system is in heavy duty, the gate terminal driving voltage of the drain terminal voltage of secondary side switches, secondary side switches and unlatching duration oscillogram.

Fig. 4 is the schematic diagram of the flyback commutation system that proposes of the present invention.

Fig. 5 is the schematic diagram of the controller of Fig. 4 flyback commutation system.

Fig. 6 be Fig. 4 flyback commutation system under the CCM pattern, the oscillogram of the electric current of secondary side switches, gate drive voltage, drain voltage and the 4th comparator output signal.

Fig. 7 be Fig. 4 flyback commutation system under the SCM pattern, the oscillogram of the drain voltage of secondary side switches, the 3rd comparator output signal and capacitance voltage.

[main element label declaration]

10,40 flyback commutation systems 1023,4023 controllers

101,401 electric power supply modules 1011,4011 stable-pressure devices

1012,4012 primary sides 1013,4013 primary side switches

102,402 electric energy receiver modules 1021,4021 secondary sides

1022,4022 secondary side switches 501 switch open modules

5,011 second comparator 5012 switch opens continue device

5,013 second with the door 502 switch closing module

5,021 first switches close closed submodule 50,211 first comparators

50212 switches cut out and continue device 50,213 first and door

5022 second switches close closed submodule 50221 time regulators

50222 the 4th comparator 50223 Ct value adjusters

5023 or the door 503 triggers

504 activation switch module 5041 the 3rd comparators

5042 load sensor C dcFilter capacitor

C LLoad capacitance C SCMElectric capacity

R dcFilter resistance R LLoad resistance

R HoldOpen duration adjusting resistance R BlankThe Ct value adjusting resistance

RMOT opening time adjusting resistance SYNC grid-control voltage

SCM is underloading pattern T very PeriodThe secondary side switches cycle

T BlankingCt value V DThe secondary side switches drain voltage

V inInput voltage V TH1Switch cuts out threshold value

V TH2Switch open threshold value V TH3Voltage

Embodiment

Please refer to Fig. 4.Fig. 4 shows the schematic diagram can avoid the flyback commutation system 40 that the both sides switch opens simultaneously.Flyback commutation system 40 comprises electric power supply module 401 and electric energy receiver module 402.Electric power supply module 401 comprises primary side 4012, and the primary side switch 4013 of stable-pressure device 4011, flyback commutation system 40.Stable-pressure device 4011 is in order to stablize the voltage of input power supply module 401, the primary side 4012 of flyback commutation system 40 is coupled to stable-pressure device 4011, in order to store the electric energy of input, primary side switch 4013 is coupled between the primary side 4012 of stable-pressure device 4011 and flyback commutation system 40, in order to the direction of the magnetic flux of the primary side 4012 of controlling flyback commutation system 40.Electric energy receiver module 402 comprises secondary side 4021, secondary side switches 4022, controller 4023, the load capacitance C of flyback commutation system 40 L, load resistance R L, filter capacitor C dc, and filter resistance R dcThe electric energy that the secondary side 4021 of flyback commutation system 40 transmits in order to the primary side 4012 of responding to flyback commutation system 40, secondary side switches 4022 are coupled to the secondary side 4021 of flyback commutation system 40, in order to open or to close electric energy receiver module 402.Controller 4023 judges whether to open secondary side switches 4022 according to the drain terminal voltage of secondary side switches 4022, and controller 4023 is also according to drain terminal voltage, the load resistance R of secondary side switches 4022 L, and cycle of secondary side switches 4022, control closing of secondary side switches 4022, controller 4023 is also according to load resistance R LSize, control whether activation of secondary side switches 4022.And filter capacitor C dc, and filter resistance R dc, be the output end voltage V that filters electric energy receiver module 402 oNoise, and will filter voltage after noise as the supply voltage of controller 4023.

When primary side switch 4013 is opened, the primary side 4012 of flyback commutation system 40 gradually has electric current and flows through, and store energy in primary side 4012, relation due to the coil flux quantitative change, primary side 4012 and secondary side 4021 polarity are opposite, A in Fig. 4, B point is high potential, so the parasitic diode of secondary side switches 4022 is by reverse bias, so do not have energy to be transferred to electric energy receiver module 402; Otherwise, when primary side switch 4013 cuts out, because disappearing, the coil flux amount cause the B point to become electronegative potential, and this moment, the parasitic diode of secondary side switches 4022 was switched on, and energy is transferred to electric energy receiver module 402, load capacitance C LBe recharged load resistance R LThere is electric current to flow through.

Please refer to Fig. 5 and Fig. 4.Fig. 5 shows the schematic diagram can avoid the controller 4023 that flyback commutation system 40 both sides switches open simultaneously.Controller 4023 comprises switch open module 501, switch closing module 502, trigger 503 and activation switch module 504.Switch open module 501 is in order to open secondary side switches 4022, and switch closing module 502 is in order to close secondary side switches 4022.Switch closing module 502 comprises the first switch and closes closed submodule 5021, second switch pass closed submodule 5022 and or door 5023.The first switch closes closed submodule 5021 and is coupled to the impedance R of the load of electric energy receiver module 402 in order to basis LSize control closing of secondary side switches 4022, second switch closes closed submodule 5022 in order to closing according to the periodic Control secondary side switches 4022 of secondary side switches 4022, or door 5023 is coupled to, and the first switch closes closed submodule 5021 and second switch closes closed submodule 5022, in order to close the output signal that closed submodule 5021 and second switch close closed submodule 5022 according to the first switch, export a signal to the replacement input of trigger 503.Trigger 503 is coupled to switch open module 501 and reaches or door 5023, controls the unlatching of secondary side switches 4022 and closes in order to the control signal of output signal output according to switch open module 501 and switch closing module 502.Trigger 503 can be rest-set flip-flop, and activation switch module 504 is in order to according to load impedance R LSize control whether activation of secondary side switches 4022.

Switch open module 501 comprise one second comparator 5011, a switch open continue device 5012, one second with door 5013, and one open duration adjuster 5014.The positive input terminal of the second comparator 5011 is coupled to voltage source V TH2(switch open threshold value), the negative input end of the second comparator 5011 is coupled to the drain electrode of secondary side switches 4022, switch open continues the positive output end that input couples trigger 503 of reseting of device 5012, second couples the output of the second comparator 5011 with door 5013 first input end, second couples the signal input part of trigger 503 with door 5013 output, the first end of opening duration adjuster 5014 is coupled to this switch open and continues device 5012, and the second end of opening duration adjuster 5012 is to be coupled to ground.

The first switch close closed submodule 5021 comprise one first comparator 50211, a switch close continue device 50212, and one first with door 50213.The positive input terminal of the first comparator 50211 is coupled to the drain electrode of secondary side switches 4022, and the negative input end of the first comparator 50211 is coupled to voltage source V TH1(switch cuts out threshold value), switch close the output that continues device 50212 be coupled to second with the second input of door 5013, switch cuts out the anti-output that input is coupled to trigger 503 of reseting that continues device 50212, first is coupled to the output of the first comparator 50211 with door 50213 first input end, first is coupled to door the second input of 50213 output that switch open continues device 5012, and first is coupled to the output of door 50213 or the first input end of door 5023.

Second switch closes closed submodule 5022 and comprises for the moment interocclusal record device 50221, one the 4th comparator 50222, an and Ct value adjuster 50223.time regulator 50221 is in order to the time span in cycle of recording secondary side switches 4022, and export the time span of two consecutive periods, the 4th comparator 50222 couple this time regulator 50221 and or the second input of door 5023, in order to receive and to compare the time span signal of two consecutive periods, and according to the difference output logic signal of the difference of the time span signal of two consecutive periods and Ct value to or the second input of door 5023, Ct value adjuster 50223 is in order to the adjustment cycle threshold value, the first end of Ct value adjuster 50223 is coupled to the 4th comparator 50222, the second end of Ct value adjuster 50223 is coupled to ground.

Activation switch module 504 comprises one the 3rd comparator 5041, reaches a load sensor 5042.The positive input terminal of the 3rd comparator 5041 is coupled to the drain electrode of secondary side switches 4022, and the negative input end of the 3rd comparator 5041 is coupled to voltage source V TH3The output of the 3rd comparator 5041 is coupled to switch and closes the set input of lasting device 50212 and the input of time regulator 50221, the input of load sensor 5042 couples the output of the 3rd comparator 5041, and load sensor 5042 is used to the impedance R of load LWhen very little, output disabled signal is with switch open module 501, switch closing module 502 and trigger 503 disableds.

Please refer to Fig. 2 and Fig. 4, under the DCM pattern, when primary side switch 4013 cut out, the coil flux amount disappeared and to cause B point in electric energy receiver module 402 to become electronegative potential and lower than switch open threshold value V TH2, secondary side switches 4022 is unlocked.Because be underload, so the electric current of the secondary side switches 4022 of flowing through is little, therefore when coil flux amount direction changed once again, the electric current of the secondary side switches of flowing through 4022 can be down to zero, and B point current potential rises and closes threshold value V over switch TH1The time, secondary side switches 4022 is closed.Because under the DCM pattern, the electric current of the secondary side switches of flowing through 4022 is little, and the drain terminal voltage of secondary side switches 4022 can't be very low, so, when primary side switch 4013 reopened, B point current potential began to rise, and B point current potential can not occur can't close threshold value V over switch TH1, make primary side switch 4013 and secondary side switches 4022 simultaneously in opening, cause the situation of circuit burnout.

Because mention that before side switch 4013 and secondary side switches 4022 can simultaneously in opening, therefore not repeat no more the action of controller 4023 under the DCM pattern here in the DCM pattern next time.Please refer to Fig. 5 under the CCM pattern, when primary side switch 4013 cut out, the coil flux amount disappeared and to cause B point in electric energy receiver module 402 to become electronegative potential (Fig. 5 V namely DBecome electronegative potential) and lower than switch open threshold value V TH2The high logic electric potential signals of comparator 5011 output this moment second give second with door 5013, switch close continue device 50212 also export high logic electric potential signal to second with door 5013, therefore, second with door 5013 be that the high logic electric potential signal of output is to the signal input part of trigger 503.Because V DIt is electronegative potential, so the first low logic electric potential signals of comparator 50211 output give first with door 50213, this moment switch open continue low logic electric potential signal that device 5012 can output continues for some time to first with door 50213, to guarantee that first hangs down the logic electric potential signals with door 50213 outputs, namely guarantee to allow the first switch close closed submodule 5021 and can not disturb secondary side switches 4022 to open.Because V DBe electronegative potential, the 3rd comparator 5041 low logic electric potential signals of output are so activation switch module 504 and second switch close not action of closed submodule.

Please refer to Fig. 5 under the CCM pattern, when primary side switch 4013 reopened, the coil flux amount changed and causes B point in electric energy receiver module 402 to become high potential (Fig. 5 V namely DBecome high potential), therefore the switch open module 501 low logic electric potential signals of output to the signal input part of trigger 503 (switch open continue device 5012 at this moment also can export the low logic electric potential signal that continues for some time to second with door 5013, be to receive low logic electric potential signal with the signal input part of guaranteeing trigger 503).Because V DHigh potential, in theory the first comparator 50211 should export high logic electric potential signal give first with door 50213, but because under the CCM pattern, the current ratio of the secondary side switches of flowing through 4022 can be down to more greatly and not zero, makes V DCan current potential higher than V TH1(switch cuts out threshold value) therefore can't close closed submodule 5021 via the first switch and close secondary side switches 4022.Because V DHigh potential, when it surpasses V TH3, the 3rd high logic electric potential signals of comparator 5041 output allow switch close to continue device 50212 to set and export low logic electric potential signal to second and 5013, and triggered time register 50221 begins to record its time, is recorded to next V always DSurpass once again V TH3, be during this period of time the period of time T of secondary side switches 4022 Period, and the 4th more double cycle of comparator 50222, when double periodic inequality less than Ct value T BlankingThe time, send that high logic electric potential signal is given or door 5023, and or door 5023 send high logic electric potential signal to the replacement input of trigger 503, causing SYNC is low logic current potential, closes secondary side switches 4022 (please refer to Fig. 6).And the present invention is closed closed submodule 5021 and second switch closes the closed submodule double insurance according to the first switch, guarantees that primary side switch 4013 and secondary side switches 4022 can not open simultaneously.

Please refer to Fig. 5, open the unlatching duration adjusting resistance R in duration adjuster 5014 Hold, capable of regulating is opened duration, the Ct value adjusting resistance R in Ct value adjuster 50223 Blank, the capable of regulating Ct value.

Except DCM and CCM pattern, flyback commutation system 40 also might be in another very underloading pattern (skip cycle mode, SCM).Namely when load is very light, primary side switch 4013 will can not opened in each cycle at this moment, and the cycle does not open several times but skip over.Therefore, embodiments of the invention increase activation switch module 504 newly, wherein comprising load sensor 5042 can be after flyback commutation system 40 enters the SCM pattern, with switch open module 501, switch closing module 502 and trigger 503 disableds, only stay activation switch module 504, so that after flyback commutation system 40 breaks away from the SCM patterns, activation switch open module 501, switch closing module 502 and trigger 503 again.Please refer to Fig. 5 and Fig. 7, after primary side switch 403 is opened, V DCurrent potential surpasses V TH3, the high logic electric potential signals of comparator 5041 output this moment the 3rd, separately after primary side switch 403 cuts out, V DCurrent potential is lower than V TH3, the logic electric potential signals are hanged down in comparator 5041 outputs this moment the 3rd.And when the 3rd comparator 5041 high logic electric potential signal of output, to the capacitor C in load sensor 5042 SCMCharging is when the 3rd comparator 5041 low logic electric potential signal of output, to the capacitor C in load sensor 5042 SCMDischarge.Due under the SCM pattern open because primary side switch 4013 will can not opened in each cycle, but the cycle that skips over several times do not open, so the charging interval significantly reduce, therefore capacitor C SCMVoltage can be down to very lowly, leave the SCM pattern, capacitor C SCMVoltage can rise constantly.In an embodiment of the present invention, with this capacitor C SCMVoltage as judging that whether flyback commutation system 40 enters the foundation of SCM pattern (judgment standard can add the magnetic hysteresis effect), works as capacitor C SCMVoltage greater than V HSCMThe time, flyback commutation system 40 leaves the SCM pattern, works as capacitor C SCMVoltage less than V LSCDuring M, flyback commutation system 40 enters the SCM pattern.Here, V HSCMAnd V LSCMDetermined by experiment.

In another embodiment of the present invention, flyback commutation system 40 can not comprise activation switch module 504, under this situation, although can't reach electricity-saving function by activation switch module 504, but flyback commutation system 40 still can close closed submodule 5022 and goes on well, problem that there will be no flyback commutation system 40 both sides switches to open simultaneously because having second switch.

In another embodiment of the present invention, flyback commutation system 40 can not comprise second switch and close closed submodule 5022, under this situation, reach although can't close closed submodule 5022 by second switch the problem of avoiding flyback commutation system 40 both sides switches to open simultaneously fully, but when flyback commutation system 40 is in utmost point underload, can reach the power saving purpose by activation switch module 504 not activation switch open modules and switch closing module.

In summary, need according to adjustment of load V compared to traditional design TH1Size, the present invention can set V TH1For relatively approaching zero negative value; even the flyback commutation system enters the CCM pattern; the electric current change of the secondary side switches of flowing through allows greatly the first switch close closed submodule can't close secondary side switches; still can close the cycle that closed submodule detects secondary side switches by second switch; to force secondary side switches to close, guarantee the fail safe of flyback commutation system before the primary side switch open.In addition, the present invention also proposes the activation switch module, when load is very light, and can be with switch open module, switch closing module and trigger disabled, to reach the power saving purpose.

The above is only preferred embodiment of the present invention, and all equalizations of doing according to claim scope of the present invention change and modify, and all should belong to covering scope of the present invention.

Claims (48)

1. flyback commutation system of avoiding the both sides switch to open simultaneously comprises:
The electric power supply module comprises:
Stable-pressure device is in order to the voltage of stable this electric power supply module of input;
The primary side of flyback commutation system is coupled to this stable-pressure device; And
The primary side switch is coupled between the primary side of this stable-pressure device and this flyback commutation system, in order to the direction of the magnetic flux of the primary side of controlling this flyback commutation system;
The electric energy receiver module comprises:
The secondary side of this flyback commutation system, the electric energy that transmits in order to the primary side of responding to this flyback commutation system;
Secondary side switches is coupled to the secondary side of this flyback commutation system; And
Controller comprises:
The switch open module is in order to open this secondary side switches;
The switch closing module, in order to close this secondary side switches, this switch closing module comprises:
The first switch closes closed submodule, controls closing of this secondary side switches in order to the size according to the impedance of a load that is coupled to this electric energy receiver module;
Second switch closes closed submodule, in order to closing according to this secondary side switches of periodic Control of this secondary side switches; And
Or door, being coupled to this first switch pass closed submodule and this second switch and closing closed submodule, the output signal of closing closed submodule in order to close closed submodule and this second switch according to this first switch is controlled closing of this secondary side switches; And
Trigger is coupled to this switch open module and is somebody's turn to do or door, in order to control the unlatching of this secondary side switches and to cut out according to the output signal of this switch open module and this switch closing module.
2. flyback commutation system according to claim 1, wherein this controller also comprises the activation switch module, in order to control the whether activation of this secondary side switches according to the size of the impedance of this load.
3. flyback commutation system according to claim 2, wherein this activation switch module comprises:
The 3rd comparator, the positive input terminal of the 3rd comparator is coupled to the drain electrode of this secondary side switches, and the negative input end of the 3rd comparator is coupled to the tertiary voltage source; And
Load sensor, the input of this load sensor is coupled to the output of the 3rd comparator, this load sensor is used to the impedance of this load when very little, and output disabled signal is with this switch open module, this switch closing module and this trigger disabled.
4. flyback commutation system according to claim 3, wherein this load sensor comprises electric capacity.
5. flyback commutation system according to claim 1, wherein this switch open module comprises:
The second comparator, the negative input end of this second comparator is coupled to the drain electrode of this secondary side switches, and the positive input terminal of this second comparator is coupled to the second voltage source;
Switch open continues device, and this switch open continues the positive output end that input couples this trigger of reseting of device;
Second with door, this second couples the output of this second comparator with the first input end of door, this second couples the signal input part of this trigger with the output of door; And
Open the duration adjuster, the first end of this unlatching duration adjuster is coupled to this switch open and continues device, and the second end of this unlatching duration adjuster is coupled to ground.
6. flyback commutation system according to claim 5, wherein this unlatching duration adjuster comprises resistance.
7. flyback commutation system according to claim 5, wherein this first switch closes closed submodule and comprises:
The first comparator, the positive input terminal of this first comparator are coupled to this drain electrode of this secondary side switches, and the negative input end of this first comparator is coupled to the first voltage source;
Switch cuts out lasting device, this switch close the output that continues device be coupled to this second with the second input of door, this switch cuts out the anti-output that input is coupled to this trigger of reseting that continues device; And
First with door, this first is coupled to the output of this first comparator with the first input end of door, this first is coupled to the second input of door the output that this switch open continues device, this first is coupled to the first input end of this or door with the output of door.
8. flyback commutation system according to claim 7, wherein this second switch closes closed submodule and comprises:
Time regulator in order to the time span in cycle of recording this secondary side switches, and is exported the time span of two consecutive periods;
The 4th comparator, couple the second input of this time regulator and this or door, in order to receiving and the time span signal of this two consecutive periods relatively, and according to the difference output logic signal of the difference of the time span signal of this two consecutive periods and a Ct value to should or this second input; And
The Ct value adjuster, in order to adjust this Ct value, the first end of this Ct value adjuster is coupled to the 4th comparator, and the second end of this Ct value adjuster is coupled to ground.
9. flyback commutation system according to claim 8, wherein this Ct value adjuster comprises resistance.
10. flyback commutation system according to claim 8, wherein this controller also comprises the activation switch module, in order to control the whether activation of this secondary side switches according to the size of the impedance of this load.
11. flyback commutation system according to claim 10, wherein this activation switch module comprises:
The 3rd comparator, the positive input terminal of the 3rd comparator is coupled to this drain electrode of this secondary side switches, the negative input end of the 3rd comparator is coupled to the tertiary voltage source, and the output of the 3rd comparator is coupled to this switch and closes the set input that continues device and the input of this time regulator; And
Load sensor, the input of this load sensor couples this output of the 3rd comparator, this load sensor is used to the impedance of this load when very little, and output disabled signal is with this switch open module, this switch closing module and this trigger disabled.
12. flyback commutation system according to claim 11, wherein this load sensor comprises electric capacity.
13. flyback commutation system according to claim 1, wherein should or the output of door couple the replacement input of this trigger.
14. flyback commutation system according to claim 1, wherein this secondary side switches is the N-type metal oxide semiconductor transistor.
15. flyback commutation system according to claim 1, wherein this trigger is rest-set flip-flop.
16. flyback commutation system according to claim 1, wherein this stable-pressure device comprises electric capacity.
17. flyback commutation system according to claim 1, wherein this primary side switch is the N-type metal oxide semiconductor transistor.
18. flyback commutation system according to claim 1, wherein this electric energy receiver module also comprises filter, be coupled to the secondary side of this controller, this secondary side switches and this flyback commutation system, in order to the noise of the output voltage that filters this electric energy receiver module.
19. a controller of avoiding flyback commutation system both sides switch to open simultaneously comprises:
The switch open module is in order to open secondary side switches;
The switch closing module, in order to close this secondary side switches, this switch closing module comprises:
The first switch closes closed submodule, controls closing of this secondary side switches in order to the size according to the impedance of a load that is coupled to the electric energy receiver module;
Second switch closes closed submodule, in order to closing according to this secondary side switches of periodic Control of this secondary side switches; And
Or door, being coupled to this first switch pass closed submodule and this second switch and closing closed submodule, the output signal of closing closed submodule in order to close closed submodule and this second switch according to this first switch is controlled closing of this secondary side switches; And
Trigger is coupled to this switch open module and is somebody's turn to do or door, in order to control the unlatching of this secondary side switches and to cut out according to the output signal of this switch open module and this switch closing module.
20. controller according to claim 19 also comprises the activation switch module, in order to control the whether activation of this secondary side switches according to the size of the impedance of this load.
21. controller according to claim 20, wherein this activation switch module comprises:
The 3rd comparator, the negative input end of the 3rd comparator are coupled to the tertiary voltage source; And
Load sensor, the input of this load sensor is coupled to the output of the 3rd comparator, this load sensor is used to the impedance of this load when very little, and output disabled signal is with this switch open module, this switch closing module and this trigger disabled.
22. controller according to claim 21, wherein this load sensor comprises electric capacity.
23. controller according to claim 19, wherein this switch open module comprises:
The second comparator, the positive input terminal of this second comparator are coupled to the second voltage source;
Switch open continues device, and this switch open continues the positive output end that input couples this trigger of reseting of device;
Second with door, this second couples the output of this second comparator with the first input end of door, this second couples the signal input part of this trigger with the output of door; And
Open the duration adjuster, the first end of this unlatching duration adjuster is coupled to this switch open and continues device, and the second end of this unlatching duration adjuster is coupled to ground.
24. controller according to claim 23, wherein this unlatching duration adjuster comprises resistance.
25. controller according to claim 23, wherein this first switch closes closed submodule and comprises:
The first comparator, the negative input end of this first comparator is coupled to the first voltage source;
Switch cuts out lasting device, this switch close the output that continues device be coupled to this second with the second input of door, this switch cuts out the anti-output that input is coupled to this trigger of reseting that continues device; And
First with door, this first is coupled to the output of this first comparator with the first input end of door, this first is coupled to the second input of door the output that this switch open continues device, this first is coupled to the first input end of this or door with the output of door.
26. controller according to claim 25, wherein this second switch closes closed submodule and comprises:
Time regulator in order to the time span in cycle of recording this secondary side switches, and is exported the time span of two consecutive periods;
The 4th comparator, couple the second input of this time regulator and this or door, in order to receiving and the time span signal of this two consecutive periods relatively, and according to the difference output logic signal of the difference of the time span signal of this two consecutive periods and a Ct value to should or this second input; And
The Ct value adjuster, in order to adjust this Ct value, the first end of this Ct value adjuster is coupled to the 4th comparator, and the second end of this Ct value adjuster is coupled to ground.
27. controller according to claim 26, wherein this Ct value adjuster comprises resistance.
28. controller according to claim 26 also comprises the activation switch module, in order to control the whether activation of this secondary side switches according to the size of the impedance of this load.
29. controller according to claim 28, wherein this activation switch module comprises:
The 3rd comparator, the negative input end of the 3rd comparator are coupled to the tertiary voltage source, and the output of the 3rd comparator is coupled to this switch and closes the set input that continues device and the input of this time regulator; And
Load sensor, the input of this load sensor couples this output of the 3rd comparator, this load sensor is used to the impedance of this load when very little, and output disabled signal is with this switch open module, this switch closing module and this trigger disabled.
30. controller according to claim 29, wherein this load sensor comprises electric capacity.
31. controller according to claim 19, wherein should or the output of door couple the replacement input of this trigger.
32. controller according to claim 19, wherein this trigger is rest-set flip-flop.
33. a flyback commutation system of avoiding the both sides switch to open simultaneously comprises:
The electric power supply module comprises:
Stable-pressure device is in order to the voltage of stable this electric power supply module of input;
The primary side of flyback commutation system is coupled to this stable-pressure device; And
The primary side switch is coupled between the primary side of this stable-pressure device and this flyback commutation system, in order to the direction of the magnetic flux of the primary side of controlling this flyback commutation system;
The electric energy receiver module comprises:
The secondary side of this flyback commutation system, the electric energy that transmits in order to the primary side of responding to this flyback commutation system;
Secondary side switches is coupled to the secondary side of this flyback commutation system; And
Controller comprises:
The switch open module is in order to open this secondary side switches;
The switch closing module is in order to control closing of this secondary side switches according to the size of impedance of a load that is coupled to this electric energy receiver module;
Trigger, be coupled to this switch open module and or the door, in order to control the unlatching of this secondary side switches and to close according to the output signal of this switch open module and this switch closing module; And
The activation switch module, in order to control the whether activation of this secondary side switches according to the size of the impedance of this load, this activation switch module comprises:
The 3rd comparator, the positive input terminal of the 3rd comparator is coupled to the drain electrode of this secondary side switches, and the negative input end of the 3rd comparator is coupled to the tertiary voltage source; And
Load sensor, the input of this load sensor is coupled to the output of the 3rd comparator, this load sensor is used to the impedance of this load when very little, and output disabled signal is with this switch open module, this switch closing module and this trigger disabled.
34. flyback commutation system according to claim 33, wherein this load sensor comprises electric capacity.
35. flyback commutation system according to claim 33, wherein this switch open module comprises:
The second comparator, the negative input end of this second comparator is coupled to the drain electrode of this secondary side switches, and the positive input terminal of this second comparator is coupled to the second voltage source;
Switch open continues device, and this switch open continues the positive output end that input couples this trigger of reseting of device;
Second with door, this second couples the output of this second comparator with the first input end of door, this second couples the signal input part of this trigger with the output of door; And
Open the duration adjuster, the first end of this unlatching duration adjuster is coupled to this switch open and continues device, and the second end of this unlatching duration adjuster is coupled to ground.
36. flyback commutation system according to claim 35, wherein this unlatching duration adjuster comprises resistance.
37. flyback commutation system according to claim 36, wherein this switch closing module comprises:
The first comparator, the positive input terminal of this first comparator are coupled to this drain electrode of this secondary side switches, and the negative input end of this first comparator is coupled to the first voltage source;
Switch cuts out lasting device, this switch close the output that continues device be coupled to this second with the second input of door, this switch cuts out the anti-output that input is coupled to this trigger of reseting that continues device; And
First with door, this first is coupled to the output of this first comparator with the first input end of door, this first is coupled to the second input of door the output that this switch open continues device, this first is coupled to the replacement input of this trigger with the output of door.
38. flyback commutation system according to claim 33, wherein this secondary side switches is the N-type metal oxide semiconductor transistor.
39. flyback commutation system according to claim 33, wherein this trigger is rest-set flip-flop.
40. flyback commutation system according to claim 33, wherein this stable-pressure device comprises electric capacity.
41. flyback commutation system according to claim 33, wherein this primary side switch is the N-type metal oxide semiconductor transistor.
42. flyback commutation system according to claim 33, wherein this electric energy receiver module also comprises filter, be coupled to the secondary side of this controller, this secondary side switches and this flyback commutation system, in order to the noise of the output voltage that filters this electric energy receiver module.
43. a controller of avoiding flyback commutation system both sides switch to open simultaneously comprises:
The switch open module is in order to open secondary side switches;
The switch closing module is in order to control closing of this secondary side switches according to the size of impedance of a load that is coupled to the electric energy receiver module;
Trigger, be coupled to this switch open module and or the door, in order to control the unlatching of this secondary side switches and to close according to the output signal of this switch open module and this switch closing module; And
The activation switch module, in order to control the whether activation of this secondary side switches according to the size of the impedance of this load, this activation switch module comprises:
The 3rd comparator, the negative input end of the 3rd comparator are coupled to the tertiary voltage source; And
Load sensor, the input of this load sensor is coupled to the output of the 3rd comparator, this load sensor is used to the impedance of this load when very little, and output disabled signal is with this switch open module, this switch closing module and this trigger disabled.
44. described controller according to claim 43, wherein this load sensor comprises electric capacity.
45. described controller according to claim 43, wherein this switch open module comprises:
The second comparator, the positive input terminal of this second comparator are coupled to the second voltage source;
Switch open continues device, and this switch open continues the positive output end that input couples this trigger of reseting of device;
Second with door, this second couples the output of this second comparator with the first input end of door, this second couples the signal input part of this trigger with the output of door; And
Open the duration adjuster, the first end of this unlatching duration adjuster is coupled to this switch open and continues device, and the second end of this unlatching duration adjuster is coupled to ground.
46. described controller according to claim 45, wherein this unlatching duration adjuster comprises resistance.
47. described controller according to claim 46, wherein this switch closing module comprises:
The first comparator, the negative input end of this first comparator is coupled to the first voltage source;
Switch cuts out lasting device, this switch close the output that continues device be coupled to this second with the second input of door, this switch cuts out the anti-output that input is coupled to this trigger of reseting that continues device; And
First with door, this first is coupled to the output of this first comparator with the first input end of door, this first is coupled to the second input of door the output that this switch open continues device, this first is coupled to the replacement input of this trigger with the output of door.
48. described controller according to claim 43, wherein this trigger is rest-set flip-flop.
CN 200910225278 2009-11-18 2009-11-18 Flyback converter system capable of avoiding simultaneous switching-on of switches on two sides CN102064723B (en)

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Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101277068A (en) * 2008-02-21 2008-10-01 崇贸科技股份有限公司 Synchronization regulation power supply convertor and synchronization regulation circuit

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101277068A (en) * 2008-02-21 2008-10-01 崇贸科技股份有限公司 Synchronization regulation power supply convertor and synchronization regulation circuit

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