CN104143901B - The control method of the control circuit and correlation of power supply changeover device - Google Patents

The control method of the control circuit and correlation of power supply changeover device Download PDF

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CN104143901B
CN104143901B CN201310161735.8A CN201310161735A CN104143901B CN 104143901 B CN104143901 B CN 104143901B CN 201310161735 A CN201310161735 A CN 201310161735A CN 104143901 B CN104143901 B CN 104143901B
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signal
current
time point
circuit
pulse
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CN104143901A (en
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林宏霖
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Richtek Technology Corp
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Richtek Technology Corp
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Abstract

The present invention proposes one of the control method of a kind of control circuit of power supply changeover device and correlation, the control circuit and includes pulse-width modulation signal generation circuit, power estimation circuitry and current limit signal generation circuit.Pulse-width modulation signal produces circuit to be used for according to current sensing signal and current limit signal and produces pulse-width modulation signal, to arrange the conducting state of the on-off circuit of power supply changeover device, with to load supplying.Power estimation circuitry estimates signal for producing power, to estimate that power supply changeover device has been exported to the energy of load.Current limit signal produces circuit and estimates signal and produce current limit signal according to power, enables power-switching circuit to export suitable energy to load.Above-described embodiment can arrange power supply changeover device and export enough energy to load, and the energy for avoiding power supply changeover device output excessive extremely loads and causes to damage, and enables the load to normal running.

Description

The control method of the control circuit and correlation of power supply changeover device
Technical field
Control circuit of the present invention about power supply changeover device, espespecially a kind of power supply that can control peak power output exactly The control method of the control circuit and correlation of converter.
Background technology
In electronic product, power supply changeover device is often used to for input power to be converted to appropriate voltage signal or electric current letter Number, to be powered to load.In order to avoid the load of power supply changeover device is damaged because excessive energy is received, power supply turns The control circuit of parallel operation must estimate and adjust the energy exported by power supply changeover device exactly.
In general power supply changeover device, control circuit estimates what power supply changeover device was exported frequently with simple mechanism Energy.However, when control circuit cannot estimate the energy exported by power supply changeover device exactly, power supply changeover device may nothing Method exports enough energy to load, and causes load normally cannot operate.Additionally, when power supply changeover device exports excessive energy Measure when load, be then likely to result in the damage of load.
However, when the resistance value of the component in power supply changeover device differs greatly, power supply changeover device be coupled to difference Voltage input power or when the voltage of input power such as changes at the situation, control circuit usually cannot be accurate Estimate the energy exported by power supply changeover device, make power supply changeover device appropriate energy may be exported to load, and cause The problem of System Operation.
Additionally, power supply changeover device may operate on continuous current mode (continuous current mode) or not Continuous current mode (discontinuous current mode), under both operating modes, general power supply changeover device The energy that control circuit cannot be exported using identical mechanism estimation power supply changeover device, and need to enter using many set circuit frameworks Row estimates, causes the increase of complexity on design on control circuit and hardware cost.
Content of the invention
In view of this, how the energy exported by power supply changeover device is estimated and adjusted to control circuit exactly, actually industry There is problem to be solved.
This specification provides a kind of embodiment of the control circuit of power supply changeover device, in order to arrange the one of a power supply changeover device The conducting state of on-off circuit, to supply power to a load, the control circuit includes:One current limit signal produces circuit, is arranged to produce A raw current limit signal;One pulse-width modulation signal produces circuit, is arranged to according to a current sensing signal and the current limit signal and produces A raw pulse-width modulation signal, to arrange the conducting state of the current switch;And a power estimation circuitry, it is arranged to according to the arteries and veins Width modulation signal, the current sensing signal and the current limit signal and produce power estimation signals;Wherein the current limit signal is produced The power estimation signals are compared by circuit with a predetermined power signal, to produce the current limit signal;The power estimation circuitry Can be according to the current sensing signal of one the 3rd time point and the current sensing signal according to one the 4th time point and one the A difference between the current sensing signal of two time points, and produce the power estimation signals;Second time point is the arteries and veins Width modulation signal maintains effective status to reach the time point of a preset ratio;It is pre- that 3rd time point is later than second time point one If time delay;4th time point is the time point that the pulse-width modulation signal is changed into disarmed state by effective status.
This specification provides a kind of embodiment of the control method of power supply changeover device, in order to arrange the one of a power supply changeover device The conducting state of on-off circuit, to supply power to a load, the control method includes:Produce a current limit signal;According to an electric current sense Survey signal and the current limit signal and produce a pulse-width modulation signal, to arrange the conducting state of the current switch;According to the pulsewidth Modulating signal, the current sensing signal and the current limit signal and produce power estimation signals;And by the power estimation signals It is compared with a predetermined power signal, to produce the current limit signal;Wherein the power estimation signals are according to one the 3rd time The current sensing signal of point and the current sensing signal and the electric current of one second time point according to one the 4th time point A difference between sensing signal and produce;It is default that second time point maintains effective status to reach one for the pulse-width modulation signal The time point of ratio;3rd time point is later than one predetermined time delay of the second time point;4th time point is the pulsewidth Modulating signal is changed into the time point of disarmed state by effective status.
One of advantage of above-described embodiment is that control circuit can arrange the enough energy of power supply changeover device output to load, And avoid power supply changeover device from exporting excessive energy to cause to damage to load, enable the load to normal running.
Another advantage of above-described embodiment is that the power estimation signals adopted by control circuit will not be subject to component Resistance value or the signal value of input power are affected.Therefore, change when the resistance value of component, power supply changeover device coupling It is connected to the input power of different voltages or when the voltage of input power changes, control circuit can right energy Enough energy for estimating that power supply changeover device is exported exactly, make power supply changeover device export appropriate energy to load.
Another advantage of above-described embodiment is to operate on continuous current mode or discontinuous current pattern when power supply changeover device When, control circuit all can estimate energy that power supply changeover device is exported using same mechanism exactly, and arrange Power convert Device exports appropriate energy to load.Therefore, complexity and hardware cost on design on control circuit all significantly can drop Low.
Other advantages of the present invention will be explained in more detail by the following description and accompanying drawing.
Description of the drawings
Accompanying drawing described herein is used for providing further understanding of the present application, constitutes the part of the application, this Shen Schematic description and description please does not constitute the improper restriction to the application for explaining the application.
Fig. 1 is the functional block diagram after the power supply changeover device simplification of one embodiment of the invention
Fig. 2 is the functional block diagram after the embodiment simplification of the control circuit of Fig. 1.
Fig. 3 is the function block after the embodiment simplification of the power estimation circuitry of Fig. 2.
Fig. 4 is the sequential chart after the embodiment simplification of the several signals in the power supply changeover device of Fig. 1.
Specific embodiment
Embodiments of the present invention are described below in conjunction with relevant drawings.In the drawings, identical label represents phase Same or similar element or or method flow.
Fig. 1 is the functional block diagram after the simplification of power supply changeover device 100 of one embodiment of the invention.Power supply changeover device 100 is wrapped Contain transformer 110, first switch circuit 120, resistance 130 and control circuit 140, with foundation input power 191 to load 192 It is powered.For making drawing simple and clear and ease of explanation, the annexation of the other elements and correlation of power supply changeover device 100 is not painted Shown in Figure 1.
In the embodiment in figure 1, transformer 110 is coupled to input power 191 and load 192, and on-off circuit 120 is coupled to Transformer 110 and resistance 130, one end of resistance 130 are coupled to preset potential V1 (for example, the current potential of earth terminal or other are suitable Current potential).Control circuit 140 is coupled to the control end of on-off circuit 120, and adopts pulse-width modulation signal (pulse width Modulation signal) PWM to be arranging the conducting state of on-off circuit 120.In the present embodiment, on-off circuit 120 is with crystalline substance The mode of body pipe is implemented, in other examples, on-off circuit 120 can also adopt various suitable active members and/or The mode of passive device is implemented.
Control circuit 140 is coupled to resistance 130, can estimate electricity according to the current sensing signal Vcs of 130 one end of resistance Source converter 100 is exported to the energy of load 192, to adjust the conducting state of on-off circuit 120.
Fig. 2 is the functional block diagram after the embodiment simplification of the control circuit 140 of Fig. 1.In the embodiment of fig. 2, control Circuit processed 140 produces circuit 210, power estimation circuitry 230 and current limit signal comprising pulse-width modulation signal and produces circuit 250.For Make drawing simple and clear and ease of explanation, the annexation of the other elements and correlation of control circuit 140 is not illustrated in Fig. 2.
Pulse-width modulation signal produces circuit 210 and is arranged to according to current sensing signal Vcs and current limit signal Vcl and produces arteries and veins Width modulation signal PWM, to arrange the conducting state of on-off circuit 120 using pulse-width modulation signal PWM.Pulse-width modulation signal is produced Circuit 210 can turn on on-off circuit 120 off and on, and the energy needed for providing power supply changeover device 100 is to load 192.Work as electric current When sensing signal Vcs is more than current limit signal Vcl, represent power supply changeover device 100 and enough energy are provided to load 192, arteries and veins Width modulation signal generating circuit 21 arranges on-off circuit 120 and assumes not on-state, to avoid power supply changeover device 100 from continuing to provide Energy is to load 192, and avoids causing the damage for loading 192.
In the embodiment of fig. 2, pulse-width modulation signal generation circuit 210 includes periodic signal generation circuit 211, first Comparison circuit 213 and SR door bolt (SR latch) circuits 215.Periodic signal produces circuit 211 and is arranged to produce periodic signal Vp, and Periodic signal Vp is exported the S inputs for fastening circuit 215 to SR with a bolt or latch.For example, periodic signal produce circuit 211 can produce pulse wave, Square wave, string involve the periodic signals such as sawtooth waveforms (ramp).Comparison circuit 213 can be according to current sensing signal Vcs and current limit signal Vcl and produce reset signal Vreset, and by reset signal Vreset export to SR fasten with a bolt or latch circuit 215 R input.Therefore, when When periodic signal Vp is high potential, pulse-width modulation signal PWM provided by the Q output of SR door bolt circuits 215 accordingly can be set High potential is set to, makes on-off circuit 120 assume conducting state.When current sensing signal Vcs is more than current limit signal Vcl, compare Reset signal Vreset can be set to high potential by circuit 213, and the PWM provided by the Q output of SR door bolt circuits 215 is believed Number PWM accordingly can be arranged to electronegative potential, make on-off circuit 120 assume not on-state.In other examples, pulsewidth Modulating signal produces circuit 210 and other suitable circuit frameworks can also be adopted to implement, with the pulse-width modulation signal needed for providing PWM.
Power estimation circuitry 230 is arranged to according to current sensing signal Vcs, current limit signal Vcl and pulse-width modulation signal PWM And power estimation signals Vspc is produced, exported with estimating power supply changeover device 100 according to the signal value of power estimation signals Vspc Energy to load 192.
Current limit signal produces circuit 250 and is arranged to according to predetermined power signal Vspt and power estimation signals Vspc and adjusts The signal value of current limit signal Vcl.
In the embodiment of fig. 2, current limit signal produces circuit 250 comprising the second comparison circuit 251, second switch circuit 253rd, resistance 255 and 257.When power estimation signals Vspc is less than predetermined power signal Vspt, comparison circuit 251 can provide height To turn on on-off circuit 253, the output current of on-off circuit 253 passes through resistance 255 and 257 to the output signal of current potential, and in electricity Node between resistance 255 and 257 produces required current limit signal Vcl.When power estimation signals Vspc is more than predetermined power signal During Vspt, comparison circuit 251 can provide the output signal of electronegative potential, make on-off circuit 253 assume not on-state.In others In embodiment, current limit signal produces circuit 250 and other suitable circuit frameworks can also be adopted to implement, with the current limliting needed for producing Signal Vcl.Therefore, it can by the signal value for arranging predetermined power signal Vspt, and then the current limit signal Vcl needed for producing, Enable pulse-width modulation signal to produce circuit 210 and the conducting state of on-off circuit 120 is set according to current limit signal Vcl, make electricity Energy needed for source converter 100 can be exported extremely loads 192.
In the embodiment of fig. 2, on-off circuit 253 is coupled to the second preset potential V2, and for example, current potential V2 may be configured as 5 Volt or other suitable current potentials.Resistance 257 is coupled to the 3rd preset potential V3, and for example, current potential V3 could be arranged to earth terminal Current potential or other suitable current potentials.
Fig. 3 is the function block after the embodiment simplification of the power estimation circuitry 230 of Fig. 2.In the fig. 3 embodiment, Power estimation circuitry 230 includes phase-locked loop circuit 310, delay circuit 320, pulse wave signal and produces circuit 331 and 332, opens Powered-down road 335,336 and 337, electric capacity 341,342 and 343, transconductance circuit (transconductance circuit) 350, ratio Circuit 381 and 382 and ramp signal generating circuit 390 are fastened with a bolt or latch compared with circuit 361,362 and 363, negative circuit 370, SR.For making Drawing is simple and clear and ease of explanation, and the annexation of the other elements and correlation of power estimation circuitry 230 is not illustrated in Fig. 3.
Phase-locked loop circuit 310 can produce half bandwidth signals PWMh according to pulse-width modulation signal PWM, by half bandwidth signals PWMh Maintain effective status (for example, signal with high level effectively represent when as high potential, signal with Low level effective represent when as low electricity Position) set of time be pulse-width modulation signal PWM maintain effective status time a preset ratio.For example, in the present embodiment In, the preset ratio is set to 1/2.
Pulse-width modulation signal PWM is carried out anti-phase computing by negative circuit 370, to be sent to the S inputs of SR door bolt circuits 381 End.Reference signal Vref and current sensing signal Vcs can be compared computing by comparison circuit 361, to be sent to SR door bolt circuits 381 R input.SR door bolts circuit 381 can provide time delay signal Tdelay to delay circuit 320 in Q output.
Delay circuit 320 can accordingly postpone half bandwidth signals PWMh according to time delay signal Tdelay, to produce half Wide postpones signal PWMhd.Half bandwidth signals PWMh maintains the time of effective status identical with half-breadth postpones signal PWMh, and half-breadth postpones Signal PWMh maintains the time of effective status to be later than the time that half bandwidth signals PWM maintains effective status.Delay circuit 320 can foundation Time delay signal Tdelay, and half-breadth postpones signal PWMh is accordingly maintained time and the half bandwidth signals PWM of effective status The lead time between the time of effective status is maintained to be set to assume proportionate relationship with time delay signal Tdelay.
Pulse wave signal produces circuit 331 and 332 and according to half bandwidth signals PWMh and half-breadth postpones signal PWMhd, and can distinguish The conducting state of the 3rd on-off circuit 335 and the 4th on-off circuit 336 is set, with respectively control electric current sensing signal Vcs to the The time that one electric capacity 341 and the second electric capacity 342 are charged or discharge.
Transconductance circuit 350 can accordingly produce current signal Itx according to the magnitude of voltage Vtx of 341 both sides of electric capacity, make electric current Signal Itx and magnitude of voltage Vtx assumes proportionate relationship.
Ramp signal generating circuit 390 is set to produce ramp signal Var, and comparison circuit 362 can be by the voltage of electric capacity 342 Value is compared computing with ramp signal Var, and comparative result is exported the S inputs for fastening circuit 382 to SR with a bolt or latch.Comparison circuit Current limit signal Vcl and ramp signal Var can be compared computing by 363, and comparative result is exported the R for fastening circuit 382 to SR with a bolt or latch Input.The Q output of SR door bolt circuits 382 can accordingly produce switch controlling signal Tdelta, to arrange the 5th on-off circuit 337 conducting state.Therefore, power estimation circuitry 230 can adjust current signal Itx pair by switch controlling signal Tdelta The charging interval of the 3rd electric capacity 343, with the power estimation signals Vspc needed for producing.
In the fig. 3 embodiment, electric capacity 341,342 and 343 is all coupled to the 4th preset potential V4 (for example, earth terminal Current potential or other suitable current potentials).In other embodiments, it is also possible to consider according to different design, and by electric capacity 341,342 And 343 be respectively coupled to identical or different current potential, and the embodiment to Fig. 3 makes corresponding modification.
Fig. 4 is the sequential chart after the embodiment simplification of the several signals in the power supply changeover device 100 of Fig. 1.Below will be with Fig. 1 to Fig. 4, further illustrates the power how control circuit 140 estimates that power supply changeover device 100 is exported.Embodiment in Fig. 4 In, time point T0 is the time that pulse-width modulation signal PWM is changed into effectively (active) state by invalid (inactive) state Point.First time point T1 is that current sensing signal Vcs corresponds to pulse-width modulation signal PWM in the change of time point T0, and produces The time point of corresponding signal value changes.Second time point T2 is that pulse-width modulation signal PWM maintains effective status to reach a default ratio The time point of example.For example, in the fig. 4 embodiment, the preset ratio is arranged to 1/2, that is, T2=(T0+T4)/2.When the 3rd Between point T3 be current sensing signal Vcs corresponding to pulse-width modulation signal PWM in the change of time point T2, and produce corresponding signal value The time point of change.4th time point T4 is the time point that pulse-width modulation signal PWM is changed into disarmed state by effective status.The Five time point T5 are that current sensing signal Vcs corresponds to pulse-width modulation signal PWM in the change of time point T4, and produce corresponding letter The time point of number value changes.
Pulse-width modulation signal PWM and the one end in resistance 130 produced by the embodiment display control circuit 140 of Fig. 4 The current sensing signal Vcs for being detected.When control circuit 140 in time point T0 using pulse-width modulation signal PWM conducting switch electricity During road 120, transformer 110 and on-off circuit 120 need one section of predetermined time delay Td, could accordingly transmit electric current to electricity Resistance 130.Therefore, during first time point T1, control circuit 140 just can detect corresponding current sensing signal in resistance 130 Vcs.
In the present embodiment, load 192 is located at the secondary side of transformer 110, and power supply changeover device 100 is carried in primary side For proportional to the energy being carried on received by the secondary side relation of energy.In first time point T0 to the 4th time point T4 When, energy P=(I (T4) × I (T4)-I (T0) × I (T0)) × L/2, wherein I that power supply changeover device 100 is provided in primary side (T0) and I (T4) is respectively the electric current that provided when time point T0 and T4 of transformer 110 in primary side, L is transformer 110 Inductance value.
The electric current I (T0) provided when time point T0 and T4 corresponding to transformer 110 and I (T4), 140 meeting of control circuit Corresponding current sensing signal Vcs (T1) and Vcs (T5), Vcs (T1)=I (T0)/R, Vcs are received respectively in time point T1 and T5 (T5) resistance value of=I (T4)/R, T1=T0+Td, T5=T4+Td, wherein R for resistance 130.Therefore, power supply changeover device 100 is in one Energy P=(Vcs (T5) × Vcs (T5)-Vcs (T1) × Vcs (T1)) × L/ (2 × R × R) provided by secondary side=(Vcs (T5)+ Vcs(T1))×(Vcs(T5)–Vcs(T1))×L/(2×R×R).
In the fig. 4 embodiment, the second time point T2=(T0+T4)/2, the 3rd time point T3=(T1+T5)/2, wherein T1= T0+Td、T3=T2+Td、T5=T4+Td.Additionally, when first time point T1 is to the 5th time point T5, current sensing signal Vcs essence The linear change of upper presentation.Therefore, the current sensing signal Vcs (T3) of the 3rd time point T3=(Vcs (T5)+Vcs (T1))/2. Additionally, Vcs (T5) Vcs (T1)=2 × (Vcs (T5) Vcs (T3))=2 × (Vcs (T4) Vcs (T2)).Power supply changeover device 100 Energy P=2 × Vcs (T3) × 2 × (Vcs (T4) Vcs (T2)) × L/ (2 × R × the R)=Vcs (T3) provided in primary side × (Vcs (T4) Vcs (T2)) × K, wherein K=2 × L/ (R × R), that is, energy P that power supply changeover device 100 is provided in primary side Proportionate relationship can be assumed with the signal value of Vcs (T3), and assume proportionate relationship with the signal value of (Vcs (T4)-Vcs (T2)).
Therefore, power estimation circuitry 230 can produce institute exactly according to Vcs (T3) and (Vcs (T4) Vcs (T2)) The power estimation signals Vspc for needing.Further, since the signal value of Vcs (T5) is not easy to measure exactly, the power of the present embodiment Estimating circuit 230 is produced according to the signal value of (Vcs (T4) Vcs (T2)) not based on the signal value of (Vcs (T5) Vcs (T3)) Raw power estimation signals Vspc, and the signal value needed using less accurate Vcs (T5) is avoided that, with needed for producing exactly Power estimation signals Vspc.
In the fig. 3 embodiment, negative circuit 370, comparison circuit 361, SR door bolt circuit 381 is arranged to according to PWM Signal PWM, reference signal Vref and current sensing signal Vcs, and produce the time delay letter corresponding to predetermined time delay Td Number Tdelay.In one embodiment, reference signal Vref is disposed proximate to 0 (for example, 0.1 volt or other are suitable of numerical value Numerical value), when pulse-width modulation signal PWM in time point S4 present electronegative potential when, negative circuit 370 can produce the output of high potential Signal fastens the S inputs of circuit 381 with a bolt or latch to SR, makes the Q output of SR door bolt circuits 381 assume high potential.When near time point S5, Current sensing signal Vcs is less than reference signal Vref, and comparison circuit 361 can produce the SR that outputs signal to of high potential and fasten circuit with a bolt or latch 381 R input, makes the Q output of SR door bolt circuits 381 assume electronegative potential.Therefore, the Q output of SR door bolts circuit 381 is exported Time delay signal Tdelay can assume effective status in time point S4 to S5, and default between time point S4 to S5 prolongs Time Td assumes proportionate relationship late.
As delay circuit 320 can accordingly postpone half bandwidth signals PWMh according to time delay signal Tdelay, to produce Raw half-breadth postpones signal PWMhd.Phase-locked loop circuit 310, delay circuit 320 and pulse wave signal generation circuit 331 can be arranged to be held Powered-down road 335 assumes conducting state in time point T1 (i.e. T0+Td) to T3 (i.e. T2+Td), makes current sensing signal Vcs by electric capacity After 341 charge or discharge, the signal value of the magnitude of voltage Vtx of 341 both sides of electric capacity assumes proportionate relationship with the signal value of Vcs (T3). Therefore, transconductance circuit 350 can assume ratio with the signal value of Vcs (T3) according to the current signal Itx produced by magnitude of voltage Vtx Relation.
Phase-locked loop circuit 310 and pulse wave signal generation circuit 332 can arrange on-off circuit 336 and in time point T0 to T2 be in Now turn on, current sensing signal Vcs is made by the signal value of 342 charge or discharge of electric capacity to Vcs (T2).Additionally, 0 in time point T4 When, current sensing signal Vcs (T4) is more than or equal to current limit signal Vcl, and pulse-width modulation signal produces circuit 21 can be by PWM Signal PWM is set to electronegative potential, and therefore current limit signal Vcl is substantially equal to Vcs (T4).
Therefore, comparison circuit 362, comparison circuit 363 and SR door bolt circuit 382 can be according to the signal value of Vcs (T2), Vcs (T4) signal value and ramp signal Var and corresponding generation switch controlling signal Tdelta, to arrange leading for on-off circuit 337 Logical state.The signal value of Vcs (T2) can be compared computing with ramp signal Var by comparison circuit 362, as ramp signal Var More than Vcs (T2) signal value when, comparison circuit 362 can produce high potential output signal to SR door bolt circuit 382 S input End, makes the switch controlling signal Tdelta produced by the Q output of SR door bolt circuits 382 assume high potential state.Comparison circuit 363 The signal value of Vcs (T4) can be compared computing with ramp signal Var, when signal values of the ramp signal Var more than Vcs (T4) When, comparison circuit 363 can produce the R input for outputing signal to SR door bolt circuits 382 of high potential, make the Q of SR door bolt circuits 382 defeated Go out the switch controlling signal Tdelta produced by end and assume low-potential state.Therefore, switch controlling signal Tdelta is presented effectively The time of state can assume proportionate relationship with the numerical value of (Vcs (T4)-Vcs (T2)), and can arrange the ON time of switch 337, Current signal Itx is made to assume proportionate relationship to the charging interval of electric capacity 343 with (Vcs (T4)-Vcs (T2)).
In the fig. 3 embodiment, the signal value of power estimation signals Vspc can assume proportionate relationship with current signal Itx, And proportionate relationship can be assumed with the signal value of current sensing signal Vcs (T3) of the 3rd time point T3.Additionally, power estimates letter The time that the signal value of number Vspc can be charged to electric capacity 337 with current signal Itx assumes proportionate relationship, and with the 4th time T4's Difference (Vcs (T4)-Vcs between the current sensing signal Vcs (T2) of current sensing signal Vcs (T4) and the second time T2 (T2)) assume proportionate relationship.Therefore, the signal value of power estimation signals Vspc can be accurately used for estimating power supply changeover device The 100 energy P provided in primary side, enable control circuit 140 accurately to arrange power supply changeover device 100 and export to load 192 energy.
In the fig. 3 embodiment, circuit blocks 301 include phase-locked loop circuit 310, delay circuit 320, pulse wave signal Produce circuit 331, on-off circuit 335, electric capacity 341, transconductance circuit 350, comparison circuit 361, negative circuit 370 and SR door bolt circuit 381, for producing the current signal Itx for assuming proportionate relationship with current sensing signal Vcs (T3).Circuit blocks 302 include There is pulse wave signal to produce circuit 332, on-off circuit 336, electric capacity 342, comparison circuit 362 and 363, SR door bolt circuit 382 and tiltedly Slope signal generating circuit 390, and phase-locked loop circuit 310 of arranging in pairs or groups is operated, so that switch controlling signal Tdelta is presented The time of effective status assumes proportionate relationship with (Vcs (T4) Vcs (T2)).
In another embodiment, it is also possible to by the embodiment for being appropriately modified Fig. 3, and current signal Itx is set to Assume proportionate relationship with (Vcs (T4) Vcs (T2)), and switch controlling signal Tdelta is presented time and the Vcs of effective status (T3) present proportionate relationship, enable the signal value of power estimation signals Vspc be accurately used for estimate power supply changeover device 100 in The energy P provided by primary side, enables control circuit 140 accurately to arrange power supply changeover device 100 and exports to the energy of load 192 Amount.
In above embodiment, power supply changeover device 100 operates on continuous current mode, and the numerical value of Vcs (T1) is not 0. In other examples, when power supply changeover device 100 operates on discontinuous current pattern, the numerical value of Vcs (T1) is 0, according to upper The formula that states, the signal value of power estimation signals Vspc are still able to be accurately used for estimating power supply changeover device 100 in primary side The energy P for being provided.Therefore, no matter control circuit 140 is operated in continuous current mode or discontinuous current pattern, all can Enough power supply changeover devices 100 that accurately arranges are exported to the energy of load 192.
In the above-described embodiment, each function block all can be realized with one or more components, and multiple Function block can be also integrated in single component.For example, pulse-width modulation signal produces the periodic signal product of circuit 210 Raw circuit 211 can also be arranged at the outside of control circuit 140, and on-off circuit 120 also can be arranged at same with control circuit 120 IC chip.
In the above-described embodiment, each signal and function block are respectively with the side of high level effectively (active high) Formula is implemented.In other embodiments, each signal and function block all can be considered according to different designs, and respectively with high level The mode of effective or Low level effective (active low) is implemented.
From preceding description, the above embodiments can accurately estimate power supply changeover device by current sensing signal The 100 energy P provided in primary side, and power supply changeover device 100 can be accurately set and exported to the energy of load 192.Cause This, control circuit can arrange power supply changeover device and export enough energy to load, and avoid power supply changeover device output excessive Energy cause to damage to loading, enable the load to normal running
Understand that the power estimation signals Vspc adopted by above-described embodiment can't be subject to circuit elements by above-mentioned formula The signal value of the resistance value or input power of part is affected.Therefore, change when the resistance value of component, Power convert Device is coupled to the input power of different voltages or when the voltage of input power changes, control circuit energy The energy exported by power supply changeover device so can be estimated exactly, make power supply changeover device appropriate energy be exported to load.
Additionally, no matter power supply changeover device can operate on continuous current mode or discontinuous current pattern, in both runnings Under pattern, control circuit can all use same mechanism, and estimate the energy exported by power supply changeover device exactly, and arrange electricity Source converter exports appropriate energy to load.Therefore, complexity and hardware cost on design on control circuit all can be big Width ground reduces.
Some vocabulary used in specification and claims are censuring specific element.Technology people in the art Member, same element may be called with different nouns.This specification and claims book is not come with the difference of title Used as the mode for distinguishing element, but the difference with element functionally is used as the benchmark that distinguishes.Will in specification and right It is open term to seek the "comprising" mentioned in book, should be construed to " comprising but be not limited to ".In addition, " coupling " word exists This includes any directly and indirectly connection means.Therefore, if the first element is coupled to the second element described in text, is represented One element can by be electrically connected with or be wirelessly transferred, the signal connected mode such as optical delivery and be attached directly to the second element, Or electrical or signal is connected to the second element indirectly by other elements or connection means.
Used herein " and/or " describing mode, any group comprising one of cited or multiple projects Close.In addition, unless specialize in specification, the term of otherwise any odd number lattice all includes the connotation of plural lattice simultaneously.
Embodiments herein is the foregoing is only, the application is not limited to, for those skilled in the art For member, the application can have various modifications and variations.All any modifications that within spirit herein and principle, is made, Equivalent, improvement etc., within the scope of all should being included in claims hereof.

Claims (8)

1. a kind of control circuit of power supply changeover device, in order to arrange the conducting state of an on-off circuit of a power supply changeover device, with Supply power to a load, it is characterised in that the control circuit includes:
One current limit signal produces circuit, is arranged to produce a current limit signal;
One pulse-width modulation signal produces circuit, is arranged to according to a current sensing signal and the current limit signal and produces pulsewidth tune Varying signal, to arrange the conducting state of the current switch;And
One power estimation circuitry, is arranged to according to the pulse-width modulation signal, the current sensing signal and the current limit signal and produces One power estimation signals;
Wherein the current limit signal is produced circuit and is compared the power estimation signals with a predetermined power signal, to produce the limit Stream signal;The power estimation circuitry can be according to the current sensing signal of one the 3rd time point and according to one the 4th time point The current sensing signal and the current sensing signal of one second time point between a difference, and produce the power and estimate letter Number;Second time point is that the pulse-width modulation signal maintains effective status to reach the time point of a preset ratio;3rd time Point is later than one predetermined time delay of the second time point;4th time point is changed into by effective status for the pulse-width modulation signal The time point of disarmed state;
The power estimation circuitry according to the pulse-width modulation signal and a time delay signal, and can arrange the current sensing signal pair One first electric capacity charges, and produces a current signal according to a magnitude of voltage of first electric capacity, make the current signal with this The current sensing signal of three time points assumes proportionate relationship.
2. control circuit as claimed in claim 1, it is characterised in that the power estimation circuitry can be according to the pulse-width modulation signal And the current limit signal and produce a switch controlling signal, when making the switch controlling signal maintain the time of effective status with the 4th Between the difference between the current sensing signal put and the current sensing signal of second time point assume proportionate relationship;Should Switch controlling signal is used for the conducting state for arranging one the 5th on-off circuit, one the 3rd electric capacity is charged with arranging the current signal And produce the power estimation signals.
3. a kind of control circuit of power supply changeover device, in order to arrange the conducting state of an on-off circuit of a power supply changeover device, with Supply power to a load, it is characterised in that the control circuit includes:
One current limit signal produces circuit, is arranged to produce a current limit signal;
One pulse-width modulation signal produces circuit, is arranged to according to a current sensing signal and the current limit signal and produces pulsewidth tune Varying signal, to arrange the conducting state of the current switch;And
One power estimation circuitry, is arranged to according to the pulse-width modulation signal, the current sensing signal and the current limit signal and produces One power estimation signals;
Wherein the current limit signal is produced circuit and is compared the power estimation signals with a predetermined power signal, to produce the limit Stream signal;The power estimation circuitry can be according to the current sensing signal of one the 3rd time point and according to one the 4th time point The current sensing signal and the current sensing signal of one second time point between a difference, and produce the power and estimate letter Number;Second time point is that the pulse-width modulation signal maintains effective status to reach the time point of a preset ratio;3rd time Point is later than one predetermined time delay of the second time point;4th time point is changed into by effective status for the pulse-width modulation signal The time point of disarmed state;
The power estimation circuitry according to the pulse-width modulation signal and the current limit signal, and can arrange the current sensing signal to one One electric capacity charges, and produces a current signal according to a magnitude of voltage of first electric capacity, when making the current signal with the 4th Between the difference between the current sensing signal put and the current sensing signal of second time point assume proportionate relationship.
4. control circuit as claimed in claim 3, it is characterised in that the power estimation circuitry can be according to the pulse-width modulation signal And one time delay signal and produce a switch controlling signal, make the switch controlling signal maintain time of effective status with this The current sensing signal of three time points assumes proportionate relationship;The switch controlling signal is used for arranging leading for one the 5th on-off circuit Logical state, charges to one the 3rd electric capacity and produces the power estimation signals to arrange the current signal.
5. a kind of control method of power supply changeover device, in order to arrange the conducting state of an on-off circuit of a power supply changeover device, with Supply power to a load, it is characterised in that the control method includes:
Produce a current limit signal;
A pulse-width modulation signal is produced according to a current sensing signal and the current limit signal, to arrange the conducting of the current switch State;
Power estimation signals are produced according to the pulse-width modulation signal, the current sensing signal and the current limit signal;And
The power estimation signals are compared with a predetermined power signal, to produce the current limit signal;
According to the pulse-width modulation signal and a time delay signal, and the current sensing signal is set one first electric capacity is charged; And
A current signal is produced according to a magnitude of voltage of first electric capacity, the electricity of the current signal and one the 3rd time point is made Stream sensing signal assumes proportionate relationship;
Wherein the power estimation signals are according to the current sensing signal of the 3rd time point and according to one the 4th time point The current sensing signal and the current sensing signal of one second time point between a difference and produce;Second time point Effective status is maintained to reach the time point of a preset ratio for the pulse-width modulation signal;3rd time point is later than second time One predetermined time delay of point;4th time point is the time that the pulse-width modulation signal is changed into disarmed state by effective status Point.
6. control method as claimed in claim 5, it is characterised in that additionally comprise:
A switch controlling signal is produced according to the pulse-width modulation signal and the current limit signal, has switch controlling signal maintenance Between the current sensing signal of the current sensing signal and second time point of the time of effect state and the 4th time point The difference assume proportionate relationship;And
The conducting state that one the 5th on-off circuit is arranged using the switch controlling signal, to arrange the current signal to one the 3rd electricity Capacity charge and produce the power estimation signals.
7. a kind of control method of power supply changeover device, in order to arrange the conducting state of an on-off circuit of a power supply changeover device, with Supply power to a load, it is characterised in that the control method includes:
Produce a current limit signal;
A pulse-width modulation signal is produced according to a current sensing signal and the current limit signal, to arrange the conducting of the current switch State;
Power estimation signals are produced according to the pulse-width modulation signal, the current sensing signal and the current limit signal;And
The power estimation signals are compared with a predetermined power signal, to produce the current limit signal;
According to the pulse-width modulation signal and the current limit signal, and the current sensing signal is set one first electric capacity is charged;And
A current signal is produced according to a magnitude of voltage of first electric capacity, the electricity of the current signal and one the 4th time point is made A difference between stream sensing signal and the current sensing signal of one second time point assumes proportionate relationship;
Wherein the power estimation signals are according to the current sensing signal of one the 3rd time point and according to the 4th time point The current sensing signal and the current sensing signal of second time point between the difference and produce;Second time point Effective status is maintained to reach the time point of a preset ratio for the pulse-width modulation signal;3rd time point is later than second time One predetermined time delay of point;4th time point is the time that the pulse-width modulation signal is changed into disarmed state by effective status Point.
8. control method as claimed in claim 7, it is characterised in that additionally comprise:
A switch controlling signal is produced according to the pulse-width modulation signal and a time delay signal, the switch controlling signal dimension is made The current sensing signal of the time and the 3rd time point of holding effective status assumes proportionate relationship;And
Be used for the conducting state that one the 5th on-off circuit is set using the switch controlling signal, the current signal is arranged to one the Three electric capacity charge and produce the power estimation signals.
CN201310161735.8A 2013-05-06 2013-05-06 The control method of the control circuit and correlation of power supply changeover device Expired - Fee Related CN104143901B (en)

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CN101527512A (en) * 2008-07-09 2009-09-09 崇贸科技股份有限公司 Bias-current limiting method and apparatus for restricting the maximum output power of power converter
CN101675577A (en) * 2007-05-02 2010-03-17 塞瑞斯逻辑公司 Switching power converter with efficient switching control signal period generation
GB2490542A (en) * 2011-05-06 2012-11-07 Texas Instr Cork Ltd Sensing arrangement for estimating the output voltage of an isolated flyback converter

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CN101675577A (en) * 2007-05-02 2010-03-17 塞瑞斯逻辑公司 Switching power converter with efficient switching control signal period generation
CN101527512A (en) * 2008-07-09 2009-09-09 崇贸科技股份有限公司 Bias-current limiting method and apparatus for restricting the maximum output power of power converter
GB2490542A (en) * 2011-05-06 2012-11-07 Texas Instr Cork Ltd Sensing arrangement for estimating the output voltage of an isolated flyback converter

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