CN103618460A - Synchronous rectification voltage reducing-flyback direct current to direct current power adaptor - Google Patents
Synchronous rectification voltage reducing-flyback direct current to direct current power adaptor Download PDFInfo
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B70/00—Technologies for an efficient end-user side electric power management and consumption
- Y02B70/10—Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes
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Abstract
A synchronous rectification voltage reducing-flyback direct current to direct current power adaptor can provide a plurality of synchronous control output ends. The adaptor provides a main output end and a synchronous converter, and second-stage output is provided by utilizing primary inductance of a voltage reducing converter. The converter needs to output level and load by utilizing a separated feedback signal, wherein each control output end provides a part of the signal, a switch controller synchronously enables a rectifying exchanger to be activated or loose effect. Switches are synchronously controlled, and therefore a power input switch becomes a control switch when each control output end is reverse.
Description
Technical field:
The present invention relates to the power supply changeover device of DC-to-DC.More particularly, the invention still further relates to by single feedback or control loop and provide voltage modulation circuit to two or more outputs.This circuit provides efficient power conversion and regulatory function in conjunction with pressure drop-flyback converter by synchronous detection technology.
Background technology:
Due to the birth of mobile electronic device, more and more for the demand of high efficiency power-switching circuit.In most of the cases, these devices are mainly battery-powered, and the time that it needs battery-powered, the longer the better.Therefore, the operating voltage of each element (as microprocessor and internal memory) becomes more and more lower, extends the life of a cell.5 volts of standards are in the past replaced by 3.3 volts, are replaced again very soon by 2.7 volts.Along with the reduction of modulation voltage, be difficult to provide one with the modulator output voltage of effective means increase, in part because the lower voltage on legacy device produces material impact (as 0.4 voltage drop of arriving 0.7V on diode).
Voltage modulator is used different technology accomplished.In a switching regulaor, the duty-cycle adjusted (switch may be serial or parallel connection) that the power supply in load is coupling in the one or more mains switches in load by control.
Switch modulator is divided into different configurations or " topology " conventionally.A topology-mono-single-ended inductor circuit comprises a relatively simple circuit, and the switch in this circuit determines that the voltage on inductor is input voltage or zero.In this way, output voltage is the function of average voltage on inductance.
The configuration of single component and the classification of single-ended inductor circuit are depended in the variation of output voltage.Such as, switch series is associated in to input and output can cause output voltage lower than input voltage.Such circuit is commonly called step-down controller.By switch is in parallel with output, output voltage can be larger than input voltage like this.Such circuit is commonly called boost converter.Step-down and booster circuit can form the output that " buck-boost " adjuster provides a polarity inversion.A unfavorable factor of these circuit is the restrictions of their coverlet modulation circuits.When having a plurality of output, use a plurality of adjusters to need a plurality of feedbacks or control loop as suitable operation, thereby increased part technical complexity and cost.
Another modulation topological structure is transformation coupled switch modulator.A kind of ability of enhancing that provides this topological structure realizes curtage gain, and the possibility of separation between the input being provided by transformer and output.In this case, single-ended inductor modulator, transformation coupling modulation device are also classified.So-called " flyback converter " is sent to output energy from input with transformer.By regulating turn ratio (N) between main transformer and auxiliary transformer, this modulator may cause voltage ratio input high or low that offers output.A unfavorable factor of flyback converter is that very high energy must obtain storing suitable operation is provided in transformer tank.This needs sizable magnetic core, may reduce the efficiency of whole circuit.
This " flyback converter " is the another kind of form of transformation coupling modulation device.In a transducer advancing, being accompanied by the extra coil of other elements need to be provided, and such as diode and resistance, this has eliminated substantially in the problem of transformer fe macro-energy energy storage in the heart.Extra winding has the armature winding of a 1:1 conventionally, helps define switching voltage when primary switch is closed.Unfortunately, the frequency range that turn ratio can limiting device is maximum frequency range 50%, under unmanageable mode above this switching current can rise.If the number of turn is reduced to increase duty-cycle when supplementing winding with money, generally only has the switching voltage of a corresponding raising degree.
Provide other combination configurations to be also fine, such as " pressure drop-flyback " transducer, to attempt to utilize the best character of different topology structure.Before, pressure drop-flyback converter utilizes a step-down controller auxiliary winding of interpolation (this winding is as the flyback converter of secondary output) that a plurality of regulation output ends are provided by producing main output.A shortcoming of these transducers is in fact to assist the power output of winding by the Power Limitation of main output.In addition,, when the load of auxiliary output is a lot, due to the transformer action of auxiliary winding, this step-down appliance will be observed the output voltage pulsation increasing.These and other shortcomings can seriously limit the opereating specification of these device inputs and output.Equally, the counterattack variation of this transducer can cause the efficiency of integrated circuit seriously to reduce.
The method addressing these problems is utilized, and adopts up to now synchronous detection can increase the operating efficiency of voltage regulator.In synchronous rectification, pair of switches is coupled in series between input voltage and ground, and they are all synchronous, input voltage or be used in the input of inductance.The Synchronization Control of these switches is compared with traditional circuit has one well to improve in efficiency.The deficiency of these synchronous circuits is, in practice, they are same, and each controlled output needs a feedback/control loop.Therefore, adjuster needs control loop that the output of 5.5 volts and 3.3 volts is provided.
In view of above-mentioned, a voltage regulator that has a plurality of regulation outputs should be provided, at user option voltage levvl, use single control loop.
Also should provide the voltage regulator of a plurality of regulation outputs, can be operated in outside the scope over input voltage and power output demand.
Also should provide in addition the voltage regulator of a plurality of regulation outputs, total power is provided can to any one regulation output, and no matter the load of other outputs.
Summary of the invention:
The object of this invention is to provide a voltage regulator that has a plurality of regulation outputs, at user option voltage levvl, use single control loop.
Another object of the present invention is to provide the voltage regulator of a plurality of regulation outputs, can be operated in outside the scope over input voltage and power output demand.
Another object of the present invention is to provide the voltage regulator of a plurality of regulation outputs, total power is provided can to any one regulation output, and no matter the load of other outputs.
Technical solution of the present invention:
According to above and other object of the present invention, a regulator that has a plurality of adjusted in concert outputs has been described.This voltage regulator utilizes synchronous rectification that the efficiency that surpasses common adjuster of improvement is provided, and provides good intersection to regulate at output simultaneously, and a step-down controller provides main output and assists flyback that one or more regulation output ends are provided.Each output has a switch, and all simultaneous operation is under the inverse state of input voltage switch.Each output end signal provides a part of a feedback signal, and these feedback signals feed back to the sequence that decides above-mentioned switch on a controller, thereby keeps high efficiency and intersect regulating.Different output may be coupled by inductance element, or output circuit may be in fact and unique output circuit being connected between magnetic-coupled element and a switch controlling signal be independently.The present invention has also introduced various selective adjusters, and wherein other quadratic functions (as soft start, overload protection, under-voltage locking) are provided.
Contrast patent documentation: CN201075822Y DC power converter 200720170131.X, the DC-DC transducer 201020183638.0 of a CN201674389U AC and DC power supply able to programme
Accompanying drawing explanation:
Above and other object of the present invention can be more obvious when with reference to the following detailed description and accompanying drawing, in these figure:
Figure 1A is the theory diagram of above-mentioned Switching Power Supply adjuster to 1F;
Fig. 2 is the theory diagram of a plurality of output buck-flyback regulator, and this demodulator provides synchro switch to each output according to principle of the present invention;
Fig. 3 is a theory diagram of the present invention, has represented a plurality of output buck-flyback synchro switch voltage regulators;
Fig. 4 is the theory diagram of a plurality of output buck-flyback regulator, and this adjuster has an independently output, and this demodulator provides synchro switch to each output according to principle of the present invention.
Embodiment:
Figure 1A-1D has shown various known topologys, and these topologys are used for realizing basic switching regulator.The output voltage that tradition step down voltage redulator provides is fewer than input voltage, and this rough schematic view as shown in Figure 1A.Step-down controller 10 comprises switch 12(S1), diode 14(D1), inductance 16(L1) and electric capacity 18(C1).Under step-down controller configuration, switch 12 is coupling in input node V conventionally
iNand between one end of inductance 16.The other end of inductance 16 is coupling in output node V
oUTon.Diode 14 be coupling in and one be formed between switch 12 and the node of inductance 16, and electric capacity 18 is coupling in V
oUTand between ground.
This output voltage is that inductance 16 is by the average voltage on switch 12.When switch 12 is closed, diode 14 is back-biased, and when switch 12 is opened, diode 14 is forward biased.The order of open and close is controlled by switch 12 regulation voltages, switch 12 is closed like this, regulation voltage higher (because it is higher to flow through the electric current of inductance 16), therefore, the duty-cycle of switch (being the time of switch 12 closures and the ratio of total time) is a key factor that determines regulator output voltage.
Figure 1B has shown a known traditional boosted switch adjuster, and the output voltage that this adjuster provides is higher than input voltage.Boost pressure controller 20 comprises switch 22(S1), diode 24(D1), inductance 26(L1) and electric capacity 28(C1).Under this regulator configuration, inductance 26 is coupling in input node V conventionally
iNand between diode 24 anodes, the negative electrode of diode 24 is coupling in output node V
oUTon.Switch 22 be coupling in and be formed between the node between inductance 26 and diode 24, two electric capacity 28 are coupling in V
oUTand between ground.
The output voltage of adjuster 20 as follows is regulated by input terminal voltage.When switch 22 is closed, diode 24 reverse bias, electric capacity 26 chargings.When switch opens, diode 24 forward bias, inductance 26 electric discharges.If switch 22 stays open, V
oUTmeeting and V
iNequate, because the electric charge on inductance 26 given out light completely, as a unique direct-current short circuit.Therefore,, until the electric charge on inductance 26 given out light completely, it provides recently from the high energy of input energy to output.The duty-cycle of this switch (in this example, having controlled a large amount of electric charges that are stored in inductance 26) can be very important when determining regulator output voltage.
Fig. 1 C has shown the topological structure of flyback adjuster.Flyback adjuster 30 comprises many assemblies identical with adjuster 20 with step down voltage redulator 10 (switch S 1, diode D1 and capacitor C 1).Difference is that the inductance in step-down and booster circuit is replaced by the T1 in circuit of reversed excitation.Transformer is formed at an armature winding 36(LPRI), one end of transformer is coupling in forward V
iNupper, the other end is coupled to negative sense V by switch 32
iNabove, secondary winding 37(LSEC) one end is coupling in negative sense V
oUTupper, the other end is coupling on the anode of diode 34.The negative electrode of diode 34 is coupling in one end of electric capacity 38, and the other end of electric capacity 38 is coupling in negative sense V
oUTon.
Ratio between LPRI and LSEC be often expressed as 1:N(wherein N be the number of turn of secondary winding and the ratio of armature winding) may be adjusted into the transmission of best power between input and output.By changing the duty-cycle of turn ratio and switch, this flyback adjuster can provide the output voltage low or higher than input voltage.When comparing with step-down, booster circuit, this adjuster provides more flexibility, but the shortcoming of doing is like this to need transformer fe to store in the heart very high energy, has therefore reduced operating efficiency.
As the positive excitation converter 40 in Fig. 1 D has been avoided storing this problem of large energy in the heart in transformer fe.The transformer 40 of this positive excitation converter comprises: (1) armature winding 56(LPTR), this winding coupled is at forward V
iNupper and by switch 42(S1) be coupling in negative sense V
iNupper, (2) secondary winding 58(LSEC) be coupled and pass through V
iNbe auxiliary winding and the diode 52(D3 of transformer T1) connect that (anode of diode is coupling in negative sense V
iNend).One end of secondary winding 58 is coupling in negative sense V
oUTend, the other end is coupling in diode 44(D1) anode.The negative electrode of diode 44 by a series of connections through filter inductor 46(L1) be coupling in forward V
oUTend.Additional diode 50(D2) anode is coupling in negative sense V
oUTend, and diode 50(D2) negative electrode is coupling between diode 44 and inductance 46.Circuit as previously described, electric capacity 48(C1) be coupling in output.
In the positive excitation converter of Fig. 1 D, when switch 42 is closed, power is transferred to load by diode 44 from input.When switch 42 is opened, diode 44 reverse bias, electric current flows through diode 50 from inductance 46.The variation of output voltage is relevant with the duty-cycle of switch 42, also relevant with the number of turn of secondary winding 58.When switch 42 is opened, auxiliary winding L AUX and diode 52 manage in the heart to clamp switching voltage and keep magnetic flux in transformer fe under zero average level.The ratio of winding L AUX and winding L PTI is generally 1:1, and this has limited duty-cycle is peaked 50%.If the number of turn of LAUX reduces, may surpass 50%, but this also causes high switching voltage, this positive excitation converter provides more output ripple than flyback converter, but is also faced with the increase (due to low duty-cycle) of input ripple current.
A plurality of output switch adjusters of previously known all embody in step-down-flyback converter 60 of Fig. 1 E.Some advantages of this converter incorporates step-down controller and flyback converter, each assembly provides a regulation output (this buck current assembly provides a regulation output, and this flyback assembly provides another adjuster output).The circuit element of this down block and step-down controller 19 configures in the same way, wherein switch 62(S1) be coupling in V
iNand between output V1 and connect with inductance 66 that (switch 62 is coupling in V
iNupper, inductance 66 is coupling on V1), diode 64(is Schottky diode preferably) be coupling in and between the node between switch 62 and inductance 66, electric capacity 68(C2) be coupling between V1 and ground.
Flyback element comprises secondary winding 76(LSEC), interact with electric capacity 66, and diode 74 is coupled in series on output V2.Resistance 70(R1) and resistance 72(C2) combination and diode 74 parallel connections.Output capacitance 78(C3) be coupling between V2 and ground.Output detections electric capacity 80 and 82(R2 and R3), be coupling in respectively output V2 and V1 upper, with resistance 84(R4) feedback signal is provided, for determining switch 62 when when open by closure.Although the hybrid circuit of Fig. 1 E provides a plurality of output from single input, but its topology has intrinsic defect, for example, when this defect appears at low output voltage (poor efficiency of flyback assembly output, due to the voltage drop on diode, it is difficult obtaining low level output).In addition, flyback assembly has limited input/output bound, it secondary output that physique regulates can be provided effectively and with relatively low efficiency limitations, among others circuit, this circuit there will be and intersects adjusting problem in the load changing.
For given input and output voltage range, the known method that improves whole energy efficiency is synchronous rectification.Fig. 1 F has shown a traditional synchronous buck converter 90, and this transducer has been modified and has comprised synchronous rectification.Step-down controller 90 comprises from V
iNby transistor switch 92(S1) and inductance 96(L1) be coupled to V
oUTon.Synchronous rectification is by stimulating transistor switch 94(S2) be added on circuit, be coupling in and switch 92 and inductance 96 between node between, switch is controlled 100 control switchs 92 and 94 and is worked in oppositely (" oppositely " means to only have at one time a switch). Switch 92 and 94 is all desirable field effect transistor (process necessary electric current and eliminate the voltage drop under any conducting state).These switches are controlled 100 by switch and are worked, so one end of inductance 96 is at V
iNand between ground.This operation has greatly been eliminated and has been occurred in the step-down of previous description diode 98 and the voltage drop in booster circuit.
The synchronous buck converter of Fig. 1 F also comprises: a Schottky diode 98(D1), this diode be coupling in and switch 92 and 94 between node between, prevent that switch 94 from opening, resistance 102(RESENSE) be coupled in series in inductance 96 and V
oUTto on-off controller 100, provide feedback signal, an electric capacity 104(C1 before) between the wire of RSENSE, carry out differential decoupling, an input capacitance 106(C being connected to
iN) be coupling in V
iNon prevent large voltage jump and AC ripple circuit paths (if desired can high frequency decoupling), an output capacitance 108(C be provided
oUT) be coupling in V
oUTon.
In a typical synchronous governor application, switch is controlled 100 one end at RSENSE and is shown output voltage, and this output voltage is coupling in C
oUTgo up and be used as reference voltage (for example 1.25 volts).On-off controller 100 synchronous control switch 92 and 94 oppositely come regulation output as function the control load electric current of desired output voltage.Although these adjusters have been obtained quite high power conversion efficiency, they only provide a single-ended regulation output.Before the output of a plurality of adjusted in concert is provided, need to a feedback loop of each output---single wire and comparator circuit.
An improved switch modulator provides a plurality of outputs, and this modulator provides synchronous rectification switch control.In preferential experience of the present invention, the duty-cycle of first switch and second and the 3rd switch are reverse.These switches are used to control first and second output voltage.The main output of this adjuster has been used step-down controller and to buck inductor, is provided additional output by coupling secondary winding, and under flyback configuration, first switch regulates electric current to flow to buck inductor coil from input.Second switch and the 3rd switch, both work in homophase, and alternately (anti-phase) first switch makes inductance coil electric discharge.
A plurality of output switch adjusters in conjunction with principle of the present invention as shown in Figure 2.Any one of a plurality of regulation outputs of Fig. 2 circuit can be fully loaded with (depending on the restriction of circuit gross output) when not considering the load of other outputs.This performance is worked circuit when needing any output without any minimum load.
There is order Closing Switch S1 by on-off controller 130 and be able to work in switching regulaor 110, corresponding, opens switch S 2 and S3.Thereby switch duty-cycle closed and that open can change regulation output voltage by 130 as required.When switch changes, the voltage ratio V on the node between switch S 1 and S2
oUT1on the high and electric current of voltage can flow to 116 li of the armature windings of T1, therefore increased the energy being stored in armature winding.Meanwhile, electric current by armature winding to C
oUT1charging.A given time interval, the output voltage based on required and load (unless V
oUT1with V
iNequate, switch S 1 remains closed in this case), switch S 1 is opened, and therefore switch S 2 and switch S 3 closures stop increasing electric current in armature winding.
Stop increasing its polarity of voltage of elementary torsion that electric current can cause transformer T1.Switch S 2 is coupled to ground by one end of elementary injection 116, thereby is coupled to capacitor C
oUT1earth terminal.This has passed through a circuit paths to armature winding makes capacitor discharge.After another given time interval, on-off controller 130 changes switch S 1, and the state of S2 and S3 also restarts circulation.If the closed sufficiently long time of switch S 2, armature winding can discharge completely in one direction and charge and (pass through V in another direction
oUT1, C
oUT1with switch S 2).This guarantees capacitor C
oUT1as " energy reservoir " when flyback output overburden and reduced output voltage provides energy to flyback parts while there is no overburden.
The order of above-mentioned event affects the secondary winding of transformer T1.When switch S 1 is opened, the be fixed on-V of voltage on elementary
oUT1(because C
oUT1elementary V ins succession
oUT1one end, the in succession one end on elementary ground of switch S 2).Switch S 3 closures and switch S 1 is opened, allow secondary voltage to capacitor C
oUT2(this voltage depends on turn ratio and V in charging
oUT1).Secondary current path is by switch S 3 and capacitor C
oUT2form a synchronous rectification flyback converter, wherein give a secondary known voltage, secondary current becomes a definite value from zero like this.
Capacitor C
oUT2average current pulse to filter out high-frequency energy less at V
oUT2on ripple.Although flow through secondary and capacitor C
oUT2on electric current must finally flow back to secondary, capacitor C as shown in the figure
oUT2do not need to be connected in V
oUT1on.Such as, capacitor C
oUT2can be coupling on replace V
oUT1.Electric current will pass through C
oUT1flow back to secondary.In the use of the synchronous rectification of secondary output by eliminating the efficiency that has increased flyback converter in conjunction with the voltage drop of conventional diode rectifier.Very Gao Shihui is clearly when only having flyback output loading for an advantage of this configuration.Under so configuring, capacitor C
oUT1can be in secondary power supply the most.C
oUT1in the energy that stores can Closing Switch S1 at ensuing one-period.In addition, the feedback of output signal is used for controlling 130(as shown in Figure 2 by single feedback conductor or in conjunction with feedback signal).
The detailed circuit diagram of a circuit is embodied in the present invention, has used as shown in Figure 3 feedback signal.In switching regulaor 200, the P-channel field-effect transistor (PEFT) pipe 202 and 203 of a pair of parallel connection has formed switch S 1.According to present load demand, utilizing single power field effect pipe is also possible as switch S 1.Switch S 2 and S3 are respectively N channel field-effect pipes 204 and 214.Although switch S 1, S2 and S3 have been used the mixing of N raceway groove and P-channel field-effect transistor (PEFT) pipe, and the configuration of other switches is also possible.Such as, switch can Dou Shi road field effect transistor or be all N channel field-effect pipe or NPN/PNP bipolar transistor.Input capacitance is the combination of four electric capacity 222,224,226 and 228, and this space of entering and the reliability of considering Single Capacitance are provided.Output capacitance C
oUT1and C
oUT2as figure forms (C by a plurality of shunt capacitances
oUT1comprise electric capacity 230,232,234 and 236, C
oUT2comprise electric capacity 238 and 240).
For Fig. 3, particularly in order to produce 3.3 volts and 5 volts of voltages, transformer T1 tri-end transformers (wherein three windings are simultaneously on same iron core).Armature winding 206 is to be connected in three strands of windings wherein between two by also series connection, and secondary winding 216 is those windings that are left.These three strands of windings have produced fabulous magnetic coupling and have improved intersection control and efficiency.These three strands of windings provide the turn ratio (because the winding that connects together of series connection and single winding are same long) of 2:1, and therefore the output of 3.3 volts and 5 volts is provided, as follows: V
oUT2=N(the turn ratio) * V
oUT1+ V
oUT1v
oUT2=0.5*3.3+3.3=4.95 volt.
The magnetic field that should also be noted that circuit needs to bear unsaturated high peak currents.Although three strands of windings are limited, circuit of the present invention is not by having the transformer of many windings can realize yet.Extra points for attention must be comprised of magnetic core, once because magnetic core soaks into, unexpectedly have serious inductance loss---a bad situation on armature winding.Therefore, be preferably in and in magnetic core, add ferro element, magnetic or Ku Er M
μ(the magnetics limited company of registration), or ferrite jaggy.Ferrocart core provides acceptable saturation characteristic conventionally, because its A.C.power loss characteristic can reduce circuit efficiency conventionally.
The switch 202,203,204 of adjuster 200 and 214 control are realized by on-off controller 250.An on-off controller 250 preferably efficient synchro switch modulator changes duty-cycle.On-off controller 250 is preferably comprised of LTC1149 high efficiency synchronous switching regulaor, can utilize the linear company from California.Detailed technical information can find in conjunction with LTC1149 in " LTC1149/LTC1149-3.3/LTC1149-5 " tables of data 1-20 page.
The circuit of Fig. 3 conventionally work is as follows.This on-off controller has been set up a duty-cycle regulation output to switch.The basis of duty-cycle is feedback signal S/D1/V to a certain extent
fBthe input of interface (feedback signal is driven by regulation output end).On-off controller is provided with an internal threshold in feedback signal.Interface SENSE+ and SENSE-detect the voltage (this voltage is directly proportional to the circuit that flows through resistance, thereby is signifying electric current) of non-essential resistance.This voltage is outside threshold value.When this threshold value is exceeded, on-off controller trigger switch changes state.All the other single cycles are by the Time dependent (when CT discharges, state before them got back to by on-off controller trigger switch and new one-period starts) that is connected on the capacitor discharge of interface CT.This on-off controller can change output signal or output loading by changing internal threshold.
More particularly, in the circuit of Fig. 3, electric capacity 242 for the PGATE port of steering circuit 250 to V
iNupper, and diode 276 is clipped in PGATE and V
iNbetween.Electric capacity 244 is coupling in charge compensation end (CAP) and V
i (REG)between end (all belonging to circuit 250), in the power supply transition period, provide electric charge to electric capacity 242.In addition, electric capacity 246 is coupling in V
i (REG)and between power ground (PGND), two electric capacity 248 are for the control frequency of on-off controller 250 is set.Electric capacity 252 and resistance 254 series connection are connected in I
tHbetween end and ground, be mainly used to the on-off controller controlled circulation frequency (thereby form transducer whole) that affords redress.
Switching regulaor 200 is controlled being provided to intersect by the reduced output voltage (3.3V) providing between by resistance 288 and 290 output and flyback output (5V) respectively.This signal is used for controlling 250(and passes through S/D1/V
fB), the voltage drop on resistance 256 is 1.25V(reference voltage like this).In this way, although a signal in conjunction with feedback signal is used, each output has been made contribution for this signal.The feedback of this separation has been introduced potential unlatching difficulty, and such as excessive possibility, but these problems can be resolved by following description.In addition, the loop that this high efficiency adjuster comprises can be by all switch opens during lower than level in advance in output loading, thus further conservation of power raising the efficiency.
Switching regulaor 200 comprises software startup circuit, comprises diode 282 and 284, electric capacity 286 and resistance 262, and this circuit is protected electronic equipment when initial start.When there is no software startup circuit, when adjuster 200 starts, duty-cycle can become 100% because output capacitance not charging completely, flyback output does not produce (this flyback output until switch S 1 is opened switch S 3 just can produce when closed).Can cause being like this conditioned and breaking load loop potentially at artificial high voltage (surpass 3.3V output).This software startup 200 just can be worked when output capacitance obtains charging fully.As shown in Figure 3, other Circnit Layouts also can be used for alleviating startup excessively to soft starting circuit.
The regulating circuit of Fig. 3 can be accomplished when using commercial parts.Such as, when using with lower component and power supply, circuit can be built and work: P channel fet: Si9435DY(comes from California, the switch 202 of Santa Clara and 203 silicon Knicks); N channel fet: Si9435DY(comes from California, the switch 204 of Santa Clara and 203 silicon Knicks); Transformer T1:HL-8700(is from electronics hurricane laboratory, the Utah State (winding 206 and 216)); Electric capacity 222,224,226 and 228:22 microfarad; Electric capacity 230,232,234,236,238 and 240:220 microfarad; Electric capacity 242:0.047 microfarad; Electric capacity 244:0.068 microfarad; Electric capacity 246:2.2 microfarad; Electric capacity 248:1000 picofarad; Electric capacity 252:2200 picofarad; Resistance 254:1K ohm; Resistance 256:24.9K ohm (1% metallic film); Electric capacity 258:56 picofarad; Resistance 260 and 262:100 ohm; Electric capacity 264:1000 picofarad; Resistance 266:0.02 ohm; Electric capacity 268:1 microfarad; Diode 270,276:BAS16(are from Philip 282 and 284 parts of De Luo Dao Zhou discrete semiconductor company); Resistance 272:33K ohm; Electric capacity 274:0.1 microfarad; Diode 278 and 280:MBRS140(from the Motorola peninsula of Phoenix, Leah Sang Na state with product); Electric capacity 286:10 microfarad; Resistance 288:102 ohm; Resistance 290:124 ohm.
A plurality of output synchronous switching regulators 300 in Fig. 4 combine principle of the present invention.Switching regulaor 300 is different from the switching regulaor 110 in Fig. 2, because the output of circuit 300 does not rely on another electric device.Switching regulaor of the present invention as previously described, switching regulaor 300 comprises a switch 312(S1), with the winding 316(L of transformer T1
pRI) series connection, 316 are connected in V
iNand V
oUT1between.V
iNalso be used to provide energy to on-off controller circuit 130, or on-off controller 130 may be independently-powered.Extra flexibility is provided this this all circuit because V
iNcan be that forward can be also reverse.Main output V
oUT1also comprise second switch 314(S2) be coupling in and between the node between switch 312 and armature winding 316, output capacitance 318 (C
oUT1) be coupling in and V
oUT1between.Feedback is by resistance 320(R1) be provided for on-off controller 130.
Second output (V of switching regulaor 300
oUT2), by electricity, from main output, isolated, be the secondary winding 326 (L by transformer T1
sEC) be coupling in main output, the winding of the magnetic core of secondary winding and armature winding 316 is the same.Switch 324(S3) be coupling between one end and ground of secondary winding, the other end of two levels 326 provides output signal V
oUT2, output capacitance 328(C
oUT2) be coupling in V
oUT2and between ground, and feedback is by resistance 322(R2) be provided for on-off controller 130.
The whole operation of switching regulaor 300 is the same with previously described switching regulaor 110 substantially.When switch S 1 is closed, electric current flows to armature winding increases the electric weight (output capacitance) being stored in winding.When S1 opens, switch S 2 and S3 be when closed, armature winding electric discharge (arrive the path on ground by switch), occurs on secondary winding that voltage (because the voltage on elementary is fixed) is to capacitor C
oUT2charging.When switch is switching once this circulation reverse, but in this case, regulation output is completely independent from one another.
The duty-cycle of switch S 1, S2 and S3 is all controlled by on-off controller, and wherein switch S 2 and S3 are operated in homophase, and that S1 is operated in is anti-phase.Although the object of adjuster be above-mentioned switch substantially can 180 the anti-phase work of degree, in this configuration, as previously mentioned, output V
oUT1and V
oUT2electrically isolated from one in essence.In addition from the single feedback signal of the combined formation of feedback signal of each output (within switch is controlled or outside), all represent, a part for two signals.
Although the present invention embodies by concrete example, above-mentioned example just should not limit the present invention for the present invention is described.It should be pointed out that as long as no departing from essence of the present invention and meeting the definition in claim, on above-mentioned example, make suitable modification and still belong to category of the present invention.
Claims (7)
1. a DC-to-DC power supply changeover device for synchronous rectification step-down-flyback, is characterized in that: foregoing circuit comprises: be coupled in series in first and second switch between electrical source voltage; First sensing element, is coupling in first end of the node between above-mentioned first and second switch, and second end is coupled first output is provided; Second sensing element, first end having is coupled to provide second output, and additional above-mentioned first sensing element; The 3rd switch, connects with above-mentioned second sensing element and makes the above-mentioned electric current that flows through second sensing element open or cut out; This control circuit be coupled Synchronization Control above-mentioned first, the duty ratio of second and the 3rd switch, above-mentioned like this second, the 3rd switch and another switch are under positive state, above-mentioned first switch is under rp state simultaneously.
2. the DC-to-DC power supply changeover device of a kind of synchronous rectification step-down-flyback according to claim 1, it is characterized in that: above-mentioned control circuit also comprises: first feedback circuit being coupled, provides first feedback signal that the magnitude of above-mentioned first output is described; Second feedback circuit being coupled, provides second feedback signal that the magnitude of above-mentioned second output is described, wherein above-mentioned first is coupled to second feedback signal the duty ratio that above-mentioned control circuit changes above-mentioned switch.
3. the DC-to-DC power supply changeover device of a kind of synchronous rectification step-down-flyback according to claim 2, is characterized in that: above-mentioned electrical source voltage is between supply voltage and zero, positive voltage and negative supply voltage, negative supply voltage and zero or positive-negative power; Above-mentioned first output is created on first output port, and above-mentioned second output is created on second output port, and above-mentioned electrical source voltage is the voltage between first input and second input; Above-mentioned the 3rd switch is coupling between first and second inductance element; Above-mentioned the 3rd switch is coupling between above-mentioned second inductance element and second output port; Above-mentioned the 3rd switch is coupling between above-mentioned second inductance element and second output port.
4. the DC-to-DC power supply changeover device of a kind of synchronous rectification step-down-flyback according to claim 3, is characterized in that: foregoing circuit also comprises: first output capacitance is coupling in above-mentioned first output; Second output capacitance is coupling in above-mentioned second output; Above-mentioned second output capacitance is coupling between above-mentioned first and second output.
5. the DC-to-DC power supply changeover device of a kind of synchronous rectification step-down-flyback according to claim 1, it is characterized in that: in this circuit, can being coupled, first provides electrical source voltage with second terminal, have a kind of method can regulate first and second output end voltage, the method comprises following step: between above-mentioned first port and first output, by first switch and first inductance element, form a circuit pathways; Between above-mentioned second port and first output, by second switch and first inductance element, form a circuit pathways; Between above-mentioned second port and second output, by the 3rd switch and second inductance element, form a circuit pathways, wherein whether above-mentioned the 3rd switch control electric current can flow through second inductance element; And be connected with second inductance element with above-mentioned first; And Synchronization Control above-mentioned first, the duty ratio of second and the 3rd switch, above-mentioned like this second, the 3rd switch and another switch are under positive state, above-mentioned first device is operated under rp state, makes first and second output controlled.
6. the DC-to-DC power supply changeover device of a kind of synchronous rectification step-down-flyback according to claim 5, it is characterized in that: the method also comprises: provide first and second feedback signal to show respectively above-mentioned first and second output, can change the duty ratio of above-mentioned switch; The method also comprises: above-mentioned first become to single feedback signal with second feedback signal; In conjunction with this single feedback signal, above-mentioned steps just can change the duty ratio of above-mentioned switch; The method also comprises: being coupled respectively and not being coupled, first arrives first and second output with second output capacitance; Wherein above-mentioned second output capacitance is coupling between above-mentioned first and second output.
7. the DC-to-DC power supply changeover device of a kind of synchronous rectification step-down-flyback according to claim 6, it is characterized in that: in this circuit, can being coupled, first provides electrical source voltage with second terminal, have a kind of method can regulate first and second output end voltage, the method comprises following step: between above-mentioned first port and first output, by first switch and first inductance element, form a circuit pathways; Between above-mentioned second port and first output, by second switch and first inductance element, form a circuit pathways; Between above-mentioned second port and second output, by the 3rd switch and second inductance element, form a circuit pathways, wherein whether above-mentioned the 3rd switch control electric current can flow through second inductance element; And be connected with second inductance element with above-mentioned first; And Synchronization Control above-mentioned first, the duty ratio of second and the 3rd switch, make first and second output controlled.
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| CN201310613135.0A CN103618460A (en) | 2013-11-27 | 2013-11-27 | Synchronous rectification voltage reducing-flyback direct current to direct current power adaptor |
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| CN201310613135.0A CN103618460A (en) | 2013-11-27 | 2013-11-27 | Synchronous rectification voltage reducing-flyback direct current to direct current power adaptor |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113078818A (en) * | 2021-04-29 | 2021-07-06 | 宁波三星医疗电气股份有限公司 | Isolated double-output DC-DC power supply and industrial control equipment |
| EP4030608A1 (en) * | 2021-01-19 | 2022-07-20 | The Boeing Company | Buck voltage regulator device |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5552695A (en) * | 1994-03-22 | 1996-09-03 | Linear Technology Corporation | Synchronously rectified buck-flyback DC to DC power converter |
-
2013
- 2013-11-27 CN CN201310613135.0A patent/CN103618460A/en active Pending
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5552695A (en) * | 1994-03-22 | 1996-09-03 | Linear Technology Corporation | Synchronously rectified buck-flyback DC to DC power converter |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP4030608A1 (en) * | 2021-01-19 | 2022-07-20 | The Boeing Company | Buck voltage regulator device |
| US11955889B2 (en) | 2021-01-19 | 2024-04-09 | The Boeing Company | Multiple-output buck voltage regulator device |
| CN113078818A (en) * | 2021-04-29 | 2021-07-06 | 宁波三星医疗电气股份有限公司 | Isolated double-output DC-DC power supply and industrial control equipment |
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