CN104143901A - Control circuit of power converter and relevant control method - Google Patents
Control circuit of power converter and relevant control method Download PDFInfo
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Abstract
The invention provides a control circuit of a power converter and a relevant control method. One control circuit of the power converter comprises a pulse-width modulation signal generation circuit, a power estimation circuit and a current-limiting signal generation circuit, wherein the pulse-width modulation signal generation circuit is used for generating a pulse-width modulation signal according to a current sensing signal and a current-limiting signal so that the closed state of a switch circuit of the power converter can be set to supply electricity to a load, the power estimation circuit is used for generating a power estimation signal so as to estimate energy which has been already output to the load by the power converter, and the current-limiting signal generation circuit generates a current-limiting signal according to the power estimation signal so that a power conversion circuit can output the appropriate amount of energy to the load. According to the control circuit of the power converter, the power converter can be set to output enough energy to the load, the situation that because a power converter outputs too much energy to the load, the load is damaged is avoided, and the load can normally work.
Description
Technical field
The present invention is about the control circuit of power supply changeover device, espespecially a kind of control circuit of the power supply changeover device that can control exactly peak power output and relevant control method.
Background technology
In electronic product, power supply changeover device is often used to input power to be converted to suitable voltage signal or current signal, so that load is powered.Load for fear of power supply changeover device is damaged because receiving excessive energy, and the energy that power supply changeover device is exported must be estimated and adjust to the control circuit of power supply changeover device exactly.
In general power supply changeover device, control circuit often adopts better simply mechanism to estimate the energy that power supply changeover device is exported.But in the time that control circuit cannot be estimated energy that power supply changeover device exports exactly, power supply changeover device may be exported enough energy to load, and causes load to operate normally.In addition,, in the time that power supply changeover device is exported too much energy to load, may cause the damage of load.
But, in the time that the resistance value of the circuit element in power supply changeover device differs greatly, power supply changeover device is coupled to the input power of different voltage or in the time of the situations such as the voltage change of input power, control circuit usually cannot be estimated the energy that power supply changeover device is exported accurately, make power supply changeover device may export suitable energy to load, and cause the problem of System Operation.
In addition, power supply changeover device may operate on continuous current mode (continuous current mode) or discontinuous current pattern (discontinuous current mode), under these two kinds of operating modes, the control circuit of general power supply changeover device cannot adopt identical mechanism to estimate the energy that power supply changeover device is exported, and need to adopt many cover circuit frameworks to estimate, cause complexity in control circuit design and the increase of hardware cost.
Summary of the invention
In view of this, how control circuit is estimated exactly and adjusts the energy that power supply changeover device is exported, in fact for industry has problem to be solved.
This specification provides a kind of embodiment of control circuit of power supply changeover device, in order to the conducting state of a switching circuit of a power supply changeover device to be set, to supply power to a load, this control circuit comprises: a current limliting signal generating circuit, be arranged to produce a current limliting signal; One pulse-width modulation signal generating circuit, is arranged to produce a pulse-width modulation signal according to a current sensing signal and this current limliting signal, so that the conducting state of this current switch to be set; And a power estimating circuit, be arranged to produce a power estimated signal according to this pulse-width modulation signal, this current sensing signal and this current limliting signal; Wherein this current limliting signal generating circuit compares this power estimated signal and a default power signal, to produce this current limliting signal; A difference between this current sensing signal and foundation this current sensing signal of one the 4th time point and this current sensing signal of one second time point of this power estimating circuit meeting foundation one the 3rd time point, and produce this power estimated signal; This second time point is the time point that this pulse-width modulation signal maintains effective status and arrive a preset ratio; The 3rd time point is later than this second time point one and presets time of delay; The 4th time point is this pulse-width modulation signal is changed into disarmed state time point by effective status.
This specification provides a kind of embodiment of control method of power supply changeover device, and in order to the conducting state of a switching circuit of a power supply changeover device to be set, to supply power to a load, this control method comprises: produce a current limliting signal; Produce a pulse-width modulation signal according to a current sensing signal and this current limliting signal, so that the conducting state of this current switch to be set; Produce a power estimated signal according to this pulse-width modulation signal, this current sensing signal and this current limliting signal; And this power estimated signal and a default power signal are compared, to produce this current limliting signal; Wherein this power estimated signal is to produce according to this current sensing signal of one the 3rd time point and according to the difference between this current sensing signal of one the 4th time point and this current sensing signal of one second time point; This second time point is the time point that this pulse-width modulation signal maintains effective status and arrive a preset ratio; The 3rd time point is later than this second time point one and presets time of delay; The 4th time point is this pulse-width modulation signal is changed into disarmed state time point by effective status.
One of advantage of above-described embodiment is that control circuit can arrange power supply changeover device and exports enough energy to load, and avoids power supply changeover device to export too much energy and cause damage to load, and load can be operated normally.
Another advantage of above-described embodiment is that power estimated signal that control circuit adopts can not be subject to the resistance value of circuit element or the signal value of input power affects.Therefore, when the resistance value of circuit element changes, power supply changeover device is coupled to different voltage input power or when in the situations such as the voltage change of input power, control circuit can so can be estimated the energy that power supply changeover device is exported exactly, makes power supply changeover device export suitable energy to load.
Another advantage of above-described embodiment is in the time that power supply changeover device operates on continuous current mode or discontinuous current pattern, control circuit all can use same mechanism to estimate exactly the energy that power supply changeover device is exported, and power supply changeover device is set exports suitable energy to load.Therefore, complexity and the hardware cost in control circuit design all can reduce significantly.
Other advantages of the present invention will explain orally in more detail by the following description and accompanying drawing.
Brief description of the drawings
Accompanying drawing described herein is used to provide further understanding of the present application, forms the application's a part, and the application's schematic description and description is used for explaining the application, does not form the improper restriction to the application.
Fig. 1 is the functional block diagram after the power supply changeover device of one embodiment of the invention is simplified
Fig. 2 is the functional block diagram after an embodiment of the control circuit of Fig. 1 simplifies.
Fig. 3 is the function square after an embodiment of the power estimating circuit of Fig. 2 simplifies.
Fig. 4 is the sequential chart after an embodiment of the several signals in the power supply changeover device of Fig. 1 simplifies.
Embodiment
Below will coordinate relevant drawings that the present invention's embodiment is described.In these accompanying drawings, identical label represents same or similar element or or method flow.
Fig. 1 is the functional block diagram after the power supply changeover device 100 of one embodiment of the invention is simplified.Power supply changeover device 100 comprises transformer 110, the first switching circuit 120, resistance 130 and control circuit 140, load 192 is powered according to input power 191.For making drawing concisely be easy to explanation, other elements of power supply changeover device 100 and relevant annexation are not illustrated in Fig. 1.
In the embodiment in figure 1, transformer 110 is coupled to input power 191 and load 192, switching circuit 120 is coupled to transformer 110 and resistance 130, and one end of resistance 130 is coupled to preset potential V1 (for example, the current potential of earth terminal or other suitable current potentials).Control circuit 140 is coupled to the control end of switching circuit 120, and adopts pulse-width modulation signal (pulse width modulation signal) PWM that the conducting state of switching circuit 120 is set.In the present embodiment, switching circuit 120 is implemented in transistorized mode, and in other embodiment, switching circuit 120 also can adopt the mode of various suitable active members and/or passive device to implement.
Control circuit 140 is coupled to resistance 130, can estimate that power supply changeover device 100 exports the energy of load 192 to according to the current sensing signal Vcs of resistance 130 one end, to adjust the conducting state of switching circuit 120.
Fig. 2 is the functional block diagram after an embodiment of the control circuit 140 of Fig. 1 simplifies.In the embodiment of Fig. 2, control circuit 140 comprises pulse-width modulation signal generating circuit 210, power estimating circuit 230 and current limliting signal generating circuit 250.For making drawing concisely be easy to explanation, other elements of control circuit 140 and relevant annexation are not illustrated in Fig. 2.
Pulse-width modulation signal generating circuit 210 is arranged to according to current sensing signal Vcs and current limliting signal Vcl and is produced pulse-width modulation signal PWM, to use pulse-width modulation signal PWM that the conducting state of switching circuit 120 is set.Pulse-width modulation signal generating circuit 210 actuating switch circuit 120 off and on, makes power supply changeover device 100 provide required energy to load 192.In the time that current sensing signal Vcs is greater than current limliting signal Vcl, represent that power supply changeover device 100 provides enough energy to load 192, pulse-width modulation signal generating circuit 21 arranges switching circuit 120 and presents not on-state, to avoid power supply changeover device 100 to continue to provide energy to load 192, and avoid causing the damage of load 192.
In the embodiment of Fig. 2, pulse-width modulation signal generating circuit 210 includes periodic signal and produces circuit 211, the first comparison circuit 213 and SR door bolt (SR latch) circuit 215.Periodic signal produces circuit 211 and is arranged to produce periodic signal Vp, and periodic signal Vp is exported to the S input of SR door bolt circuit 215.For example, periodic signal produces circuit 211 and can produce pulse wave, square wave, string and involve the periodic signals such as sawtooth waveforms (ramp).Comparison circuit 213 can produce reset signal Vreset according to current sensing signal Vcs and current limliting signal Vcl, and reset signal Vreset is exported to the R input of SR door bolt circuit 215.Therefore,, in the time that periodic signal Vp is high potential, the pulse-width modulation signal PWM that the Q output of SR door bolt circuit 215 provides can be set to high potential accordingly, makes switching circuit 120 present conducting state.In the time that current sensing signal Vcs is greater than current limliting signal Vcl, comparison circuit 213 can be set to high potential by reset signal Vreset, the pulse-width modulation signal PWM that the Q output of SR door bolt circuit 215 provides can be set to electronegative potential accordingly, makes switching circuit 120 present not on-state.In other embodiment, pulse-width modulation signal generating circuit 210 also can adopt other suitable circuit frameworks to implement, so that required pulse-width modulation signal PWM to be provided.
Power estimating circuit 230 is arranged to according to current sensing signal Vcs, current limliting signal Vcl and pulse-width modulation signal PWM and is produced power estimated signal Vspc, to estimate that according to the signal value of power estimated signal Vspc power supply changeover device 100 exports the energy of load 192 to.
Current limliting signal generating circuit 250 is arranged to adjust according to presetting power signal Vspt and power estimated signal Vspc the signal value of current limliting signal Vcl.
In the embodiment of Fig. 2, current limliting signal generating circuit 250 comprises the second comparison circuit 251, second switch circuit 253, resistance 255 and 257.In the time that power estimated signal Vspc is less than default power signal Vspt, comparison circuit 251 can provide the output signal of high potential with actuating switch circuit 253, the output current of switching circuit 253 is by resistance 255 and 257, and node between resistance 255 and 257 produces required current limliting signal Vcl.In the time that power estimated signal Vspc is greater than default power signal Vspt, comparison circuit 251 can provide the output signal of electronegative potential, makes switching circuit 253 present not on-state.In other embodiment, current limliting signal generating circuit 250 also can adopt other suitable circuit frameworks to implement, to produce required current limliting signal Vcl.Therefore, can be by the signal value that default power signal Vspt is set, and then produce required current limliting signal Vcl, make pulse-width modulation signal generating circuit 210 that the conducting state of switching circuit 120 can be set according to current limliting signal Vcl, make power supply changeover device 100 can export required energy to load 192.
In the embodiment of Fig. 2, switching circuit 253 is coupled to the second preset potential V2, and for example, current potential V2 can be set to 5 volts or other suitable current potentials.Resistance 257 is coupled to the 3rd preset potential V3, and for example, current potential V3 can be set to current potential or other suitable current potentials of earth terminal.
Fig. 3 is the function square after an embodiment of the power estimating circuit 230 of Fig. 2 simplifies.In the embodiments of figure 3, power estimating circuit 230 include phase-locked loop circuit 310, delay circuit 320, pulse wave signal produce circuit 331 and 332, switching circuit 335,336 and 337, electric capacity 341,342 and 343, transconductance circuit (transconductance circuit) 350, comparison circuit 361,362 and 363, negative circuit 370, SR door bolt circuit 381 and 382 and ramp signal produce circuit 390.For making drawing concisely be easy to explanation, other elements of power estimating circuit 230 and relevant annexation are not illustrated in Fig. 3.
Phase-locked loop circuit 310 can produce half bandwidth signals PWMh according to pulse-width modulation signal PWM, half bandwidth signals PWMh (is for example maintained to effective status, when signal effectively represents taking high level, as high potential, signal is electronegative potential while expression taking Low level effective) set of time maintain the preset ratio of the time of effective status as pulse-width modulation signal PWM.For example, in the present embodiment, this 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 input of SR door bolt circuit 381.Comparison circuit 361 can compare computing with reference to signal Vref and current sensing signal Vcs, to be sent to the R input of SR door bolt circuit 381.SR door bolt circuit 381 can provide time of delay signal Tdelay to delay circuit 320 in Q output.
Delay circuit 320 can be according to signal Tdelay and postpone accordingly half bandwidth signals PWMh time of delay, to produce half-breadth inhibit signal PWMhd.Half bandwidth signals PWMh is identical with the time that half-breadth inhibit signal PWMh maintains effective status, and the time that half-breadth inhibit signal PWMh maintains effective status is later than half bandwidth signals PWM and maintains the time of effective status.Delay circuit 320 can be according to signal Tdelay time of delay, and accordingly half-breadth inhibit signal PWMh maintain lead time between the time that time of effective status and half bandwidth signals PWM maintain effective status be set to time of delay signal Tdelay present proportionate relationship.
Pulse wave signal produces circuit 331 and 332 can be according to half bandwidth signals PWMh and half-breadth inhibit signal PWMhd, and the conducting state of the 3rd switching circuit 335 and the 4th switching circuit 336 is set respectively, the time of the first electric capacity 341 and the second electric capacity 342 being carried out to charge or discharge to control respectively current sensing signal Vcs.
Transconductance circuit 350 can be according to the magnitude of voltage Vtx of electric capacity 341 both sides generation current signal Itx accordingly, make current signal Itx and magnitude of voltage Vtx present proportionate relationship.
Ramp signal produces circuit 390 and is set to produce ramp signal Var, and comparison circuit 362 can compare computing by the magnitude of voltage of electric capacity 342 and ramp signal Var, and comparative result is exported to the S input of SR door bolt circuit 382.Comparison circuit 363 can compare computing by current limliting signal Vcl and ramp signal Var, and comparative result is exported to the R input of SR door bolt circuit 382.The Q output of SR door bolt circuit 382 can produce switch controlling signal Tdelta accordingly, so that the conducting state of the 5th switching circuit 337 to be set.Therefore, power estimating circuit 230 can be adjusted the charging interval of current signal Itx to the 3rd electric capacity 343 by switch controlling signal Tdelta, to produce required power estimated signal Vspc.
In the embodiments of figure 3, electric capacity 341,342 and 343 is all coupled to the 4th preset potential V4 (for example, the current potential of earth terminal or other suitable current potentials).In other embodiments, also can consider according to different designs, and electric capacity 341,342 and 343 is coupled to respectively to identical or different current potential, and the embodiment of Fig. 3 is made to corresponding amendment.
Fig. 4 is the sequential chart after an embodiment of the several signals in the power supply changeover device 100 of Fig. 1 simplifies.Below will be with Fig. 1 to Fig. 4, further illustrate control circuit 140 and how to estimate the power that power supply changeover device 100 is exported.In the embodiment of Fig. 4, time point T0 is that pulse-width modulation signal PWM is the time point of effective (active) state by invalid (inactive) state-transition.Very first time point T1 be current sensing signal Vcs corresponding to pulse-width modulation signal PWM in the variation of time point T0, and produce the time point that respective signal value changes.The second time point T2 is the time point that pulse-width modulation signal PWM maintains effective status and arrive a preset ratio.For example, in the embodiment of Fig. 4, this preset ratio is set to 1/2, that is T2=(T0+T4)/2.The 3rd time point T3 be current sensing signal Vcs corresponding to pulse-width modulation signal PWM in the variation of time point T2, and produce the time point that respective signal value changes.The 4th time point T4 is pulse-width modulation signal PWM is changed into disarmed state time point by effective status.The 5th time point T5 be current sensing signal Vcs corresponding to pulse-width modulation signal PWM in the variation of time point T4, and produce the time point that respective signal value changes.
The pulse-width modulation signal PWM that the embodiment display control circuit 140 of Fig. 4 produces and the current sensing signal Vcs detecting in one end of resistance 130.When control circuit 140 is in the time that time point T0 uses pulse-width modulation signal PWM actuating switch circuit 120, transformer 110 and switching circuit 120 need one section default time of delay Td, electric current could be transferred to resistance 130 accordingly.Therefore,, when very first time point T1, control circuit 140 just can detect corresponding current sensing signal Vcs in resistance 130.
In the present embodiment, load 192 is positioned at the secondary side of transformer 110, and the energy that power supply changeover device 100 provides in primary side be carried on the proportional relation of the received energy of secondary side.In the time of very first time point T0 to the four time point T4, energy P=(I (T4) × I (T4)-I (T0) × I (T0)) × L/2 that power supply changeover device 100 provides in primary side, wherein I (T0) and I (T4) are respectively the electric current that transformer 110 provides in primary side in the time of time point T0 and T4, and L is the inductance value of transformer 110.
The electric current I (T0) and the I (T4) that provide when time point T0 and the T4 corresponding to transformer 110, control circuit 140 can receive respectively corresponding current sensing signal Vcs (T1) and Vcs (T5), Vcs (T1)=I (T0)/R, Vcs (T5)=I (T4)/R, T1=T0+Td, T5=T4+Td in time point T1 and T5, and wherein R is the resistance value of resistance 130.Therefore energy P=(Vcs (T5) × Vcs (T5)-Vcs (T1) × Vcs (T1)) × L/ (2 × R × R)=(Vcs (T5)+Vcs (T1)) × (Vcs (T5) – Vcs (T1)) × L/ (2 × R × R) that, power supply changeover device 100 provides in primary side.
In the embodiment of Fig. 4, the second time point T2=(T0+T4)/2, the three time point T3=(T1+T5)/2, wherein T1=T0+Td, T3=T2+Td, T5=T4+Td.In addition,, when very first time point T1 to the five time point T5, current sensing signal Vcs presents in fact linear variation.Therefore, the current sensing signal Vcs (T3) of the 3rd time point T3=(Vcs (T5)+Vcs (T1))/2.In addition Vcs (T5) – Vcs (T1)=2 × (Vcs (T5) – Vcs (T3))=2 × (Vcs (T4) – Vcs (T2)).Energy P=2 × Vcs (T3) × 2 × (Vcs (T4) – Vcs (T2)) × L/ (2 × R × R)=Vcs (T3) × (Vcs (T4) – Vcs (T2)) × K that power supply changeover device 100 provides in primary side, wherein K=2 × L/ (R × R), that is the energy P that power supply changeover device 100 provides in primary side can present proportionate relationship with the signal value of Vcs (T3), and present proportionate relationship with the signal value of (Vcs (T4)-Vcs (T2)).
Therefore, power estimating circuit 230 can be according to Vcs (T3) and (Vcs (T4) – Vcs (T2)) and produce exactly required power estimated signal Vspc.In addition, because the signal value of Vcs (T5) is not easy to measure exactly, the power estimating circuit 230 of the present embodiment is not based on (the signal value of Vcs (T5) – Vcs (T3)) and according to (signal value of Vcs (T4) – Vcs (T2)) produces power estimated signal Vspc, and can avoid need use more inaccurate Vcs (T5) signal value, to produce exactly required power estimated signal Vspc.
In the embodiments of figure 3, negative circuit 370, comparison circuit 361, SR door bolt circuit 381 are arranged to according to pulse-width modulation signal PWM, reference signal Vref and current sensing signal Vcs, and produce corresponding to signal Tdelay time of delay that presets Td time of delay.In one embodiment, (be for example set to approach 0 numerical value with reference to signal Vref, 0.1 volt or other suitable numerical value), when pulse-width modulation signal PWM is in the time that time point S4 presents electronegative potential, negative circuit 370 can produce the S input that outputs signal to SR door bolt circuit 381 of high potential, makes the Q output of SR door bolt circuit 381 present high potential.Near time point S5 time, current sensing signal Vcs is less than reference signal Vref, and comparison circuit 361 can produce the R input that outputs signal to SR door bolt circuit 381 of high potential, makes the Q output of SR door bolt circuit 381 present electronegative potential.Therefore, signal Tdelay time of delay that the Q output of SR door bolt circuit 381 is exported can present effective status in time point S4 to S5, and and default time of delay of Td between time point S4 to S5 present proportionate relationship.
Because delay circuit 320 can be according to signal Tdelay and postpone accordingly half bandwidth signals PWMh time of delay, to produce half-breadth inhibit signal PWMhd.Phase-locked loop circuit 310, delay circuit 320 and pulse wave signal generation circuit 331 can arrange switching circuit 335 and present conducting state in time point T1 (being T0+Td) to T3 (being T2+Td), make current sensing signal Vcs by after electric capacity 341 charge or discharge, the signal value of the signal value of the magnitude of voltage Vtx of electric capacity 341 both sides and Vcs (T3) presents proportionate relationship.Therefore the current signal Itx that, transconductance circuit 350 produces according to magnitude of voltage Vtx can present proportionate relationship with the signal value of Vcs (T3).
Phase-locked loop circuit 310 and pulse wave signal produce circuit 332 and switching circuit 336 can be set present conducting in time point T0 to T2, make current sensing signal Vcs by electric capacity 342 charge or discharge the signal value to Vcs (T2).In addition, 0 in the time of time point T4, current sensing signal Vcs (T4) is more than or equal to current limliting signal Vcl, and pulse-width modulation signal generating circuit 21 can be set to electronegative potential by pulse-width modulation signal PWM, and therefore current limliting signal Vcl equals in fact Vcs (T4).
Therefore, comparison circuit 362, comparison circuit 363 and SR door bolt circuit 382 can be according to the signal value of the signal value of Vcs (T2), Vcs (T4) and ramp signal Var and corresponding generation switch controlling signal Tdelta, so that the conducting state of switching circuit 337 to be set.Comparison circuit 362 can compare computing by the signal value of Vcs (T2) and ramp signal Var, in the time that ramp signal Var is greater than the signal value of Vcs (T2), comparison circuit 362 can produce the S input that outputs signal to SR door bolt circuit 382 of high potential, and the switch controlling signal Tdelta that the Q output of SR door bolt circuit 382 is produced presents high potential state.Comparison circuit 363 can compare computing by the signal value of Vcs (T4) and ramp signal Var, in the time that ramp signal Var is greater than the signal value of Vcs (T4), comparison circuit 363 can produce the R input that outputs signal to SR door bolt circuit 382 of high potential, and the switch controlling signal Tdelta that the Q output of SR door bolt circuit 382 is produced presents low-potential state.Therefore, the time that switch controlling signal Tdelta presents effective status can present proportionate relationship with the numerical value of (Vcs (T4)-Vcs (T2)), and the ON time of switch 337 can be set, make current signal Itx present proportionate relationship to the charging interval of electric capacity 343 with (Vcs (T4)-Vcs (T2)).
In the embodiments of figure 3, the signal value of power estimated signal Vspc can present proportionate relationship with current signal Itx, and can present proportionate relationship with the signal value of this current sensing signal Vcs (T3) of the 3rd time point T3.In addition, the signal value of power estimated signal Vspc can present proportionate relationship with the time that current signal Itx charges to electric capacity 337, and and difference (Vcs (T4)-Vcs (T2)) between the current sensing signal Vcs (T4) of the 4th time T 4 and the current sensing signal Vcs (T2) of the second time T 2 present proportionate relationship.Therefore, the signal value of the power estimated signal Vspc energy P for estimating that power supply changeover device 100 provides in primary side exactly, makes control circuit 140 can power supply changeover device 100 be accurately set to export to the energy of load 192.
In the embodiments of figure 3, circuit blocks 301 includes phase-locked loop circuit 310, delay circuit 320, pulse wave signal generation circuit 331, switching 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 that presents proportionate relationship with current sensing signal Vcs (T3).Circuit blocks 302 includes pulse wave signal and produces circuit 332, switching circuit 336, electric capacity 342, comparison circuit 362 and 363, SR door bolt circuit 382 and ramp signal generation circuit 390, and the phase-locked loop circuit 310 of arranging in pairs or groups operates, so that presenting the time of effective status, switch controlling signal Tdelta presents proportionate relationship with (Vcs (T4) – Vcs (T2)).
In another embodiment, also can be by the embodiment that suitably revises Fig. 3, and current signal Itx is set to (Vcs (T4) – Vcs (T2)) presents proportionate relationship, and time and Vcs (T3) that switch controlling signal Tdelta presents effective status are presented to proportionate relationship, make the signal value energy P for estimating that power supply changeover device 100 provides in primary side exactly of power estimated signal Vspc, make control circuit 140 can power supply changeover device 100 be accurately set to export to the energy of load 192.
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 embodiment, when power supply changeover device 100 operates on discontinuous current pattern, the numerical value of Vcs (T1) is 0, according to above-mentioned formula, and the still energy P for estimating that power supply changeover device 100 provides in primary side exactly of the signal value of power estimated signal Vspc.Therefore, no matter control circuit 140 operates in the time of continuous current mode or discontinuous current pattern, all can power supply changeover device 100 be accurately set and export to the energy of load 192.
In the above-described embodiment, each function square all can be realized with one or more circuit elements, and multiple function square also can be integrated in single circuit element.For example, the periodic signal generation circuit 211 of pulse-width modulation signal generating circuit 210 also can be arranged at the outside of control circuit 140, and switching circuit 120 also can be arranged at same integrated circuit (IC) chip with control circuit 120.
In the above-described embodiment, each signal and function square are implemented in the mode of high level effective (active high) respectively.In other embodiments, each signal and function square all can be considered according to different designs, and mode effective with high level or Low level effective (active low) is implemented respectively.
From above stated specification, the above embodiments can be estimated accurately by current sensing signal the energy P that power supply changeover device 100 provides in primary side, and can power supply changeover device 100 be accurately set and export to the energy of load 192.Therefore, control circuit can arrange power supply changeover device and export enough energy to load, and avoids power supply changeover device to export too much energy and cause damage to load, and load can be operated normally
Known by above-mentioned formula, the power estimated signal Vspc that above-described embodiment adopts can't be subject to the resistance value of circuit element or the signal value of input power affects.Therefore, when the resistance value of circuit element changes, power supply changeover device is coupled to different voltage input power or when in the situations such as the voltage change of input power, control circuit can so can be estimated the energy that power supply changeover device is exported exactly, makes power supply changeover device export suitable energy to load.
In addition, no matter power supply changeover device can operate on continuous current mode or discontinuous current pattern, and under these two kinds of operating modes, control circuit all can use same mechanism, and estimate exactly the energy that power supply changeover device is exported, and power supply changeover device is set exports suitable energy to load.Therefore, complexity and the hardware cost in control circuit design all can reduce significantly.
In specification and claims, use some vocabulary to censure specific element.Those skilled in the art, same element may be called with different nouns.This specification and claims book is not used as distinguishing the mode of element with the difference of title, but the difference in function is used as the benchmark of distinguishing with element." comprising " mentioned in specification and claims is open term, should be construed to " comprise but be not limited to ".In addition, " coupling " word comprises directly any and indirectly connects means at this.Therefore, be coupled to the second element if describe the first element in literary composition, represent that the first element can directly be connected in the second element by the signal such as electric connection or wireless transmission, optical delivery connected mode, or by other element or connection means indirectly electrically or signal be connected to the second element.
Used herein " and/or " describing mode, comprise cited one of them or the combination in any of multiple projects.In addition, unless in specification, specialize, the term of any odd number lattice all comprises the connotation of plural lattice simultaneously.
The embodiment that the foregoing is only the application, is not limited to the application, and for a person skilled in the art, the application can have various modifications and variations.All within the application's spirit and principle, any amendment of doing, be equal to replacement, improvement etc., within all should being included in the application's claim scope.
Claims (10)
1. a control circuit for power supply changeover device, in order to the conducting state of a switching circuit of a power supply changeover device to be set, to supply power to a load, is characterized in that, this control circuit comprises:
One current limliting signal generating circuit, is arranged to produce a current limliting signal;
One pulse-width modulation signal generating circuit, is arranged to produce a pulse-width modulation signal according to a current sensing signal and this current limliting signal, so that the conducting state of this current switch to be set; And
One power estimating circuit, is arranged to produce a power estimated signal according to this pulse-width modulation signal, this current sensing signal and this current limliting signal;
Wherein this current limliting signal generating circuit compares this power estimated signal and a default power signal, to produce this current limliting signal; A difference between this current sensing signal and foundation this current sensing signal of one the 4th time point and this current sensing signal of one second time point of this power estimating circuit meeting foundation one the 3rd time point, and produce this power estimated signal; This second time point is the time point that this pulse-width modulation signal maintains effective status and arrive a preset ratio; The 3rd time point is later than this second time point one and presets time of delay; The 4th time point is this pulse-width modulation signal is changed into disarmed state time point by effective status.
2. control circuit as claimed in claim 1, it is characterized in that, this power estimating circuit can according to this pulse-width modulation signal and one time of delay signal, and this current sensing signal is set to one first capacitor charging, and produce a current signal according to a magnitude of voltage of this first electric capacity, make this current sensing signal of this current signal and the 3rd time point present proportionate relationship.
3. control circuit as claimed in claim 2, it is characterized in that, this power estimating circuit can be according to this pulse-width modulation signal and this current limliting signal and is produced a switch controlling signal, and this difference that this switch controlling signal is maintained between time and this current sensing signal of the 4th time point and this current sensing signal of this second time point of effective status presents proportionate relationship; This switch controlling signal, for the conducting state of one the 5th switching circuit is set, produces this power estimated signal so that this current signal to be set to one the 3rd capacitor charging.
4. control circuit as claimed in claim 1, it is characterized in that, this power estimating circuit can be according to this pulse-width modulation signal and this current limliting signal, and this current sensing signal is set to one first capacitor charging, and produce a current signal according to a magnitude of voltage of this first electric capacity, make this difference between this current signal and this current sensing signal of the 4th time point and this current sensing signal of this second time point present proportionate relationship.
5. control circuit as claimed in claim 4, it is characterized in that, this power estimating circuit can according to this pulse-width modulation signal and one time of delay signal and produce a switch controlling signal, make this switch controlling signal maintain the time of effective status and this current sensing signal of the 3rd time point presents proportionate relationship; This switch controlling signal, for the conducting state of one the 5th switching circuit is set, produces this power estimated signal so that this current signal to be set to one the 3rd capacitor charging.
6. a control method for power supply changeover device, in order to the conducting state of a switching circuit of a power supply changeover device to be set, to supply power to a load, is characterized in that, this control method comprises:
Produce a current limliting signal;
Produce a pulse-width modulation signal according to a current sensing signal and this current limliting signal, so that the conducting state of this current switch to be set;
Produce a power estimated signal according to this pulse-width modulation signal, this current sensing signal and this current limliting signal; And
This power estimated signal and a default power signal compare, to produce this current limliting signal;
Wherein this power estimated signal is to produce according to this current sensing signal of one the 3rd time point and according to the difference between this current sensing signal of one the 4th time point and this current sensing signal of one second time point; This second time point is the time point that this pulse-width modulation signal maintains effective status and arrive a preset ratio; The 3rd time point is later than this second time point one and presets time of delay; The 4th time point is this pulse-width modulation signal is changed into disarmed state time point by effective status.
7. control method as claimed in claim 6, is characterized in that, separately comprises:
According to this pulse-width modulation signal and one time of delay signal, and this current sensing signal is set to one first capacitor charging; And
Produce a current signal according to a magnitude of voltage of this first electric capacity, make this current sensing signal of this current signal and the 3rd time point present proportionate relationship.
8. control method as claimed in claim 7, is characterized in that, separately comprises:
According to this pulse-width modulation signal and this current limliting signal and produce a switch controlling signal, this difference that this switch controlling signal is maintained between time and this current sensing signal of the 4th time point and this current sensing signal of this second time point of effective status presents proportionate relationship; And
Use this switch controlling signal that the conducting state of one the 5th switching circuit is set, so that this current signal to be set, one the 3rd capacitor charging is produced to this power estimated signal.
9. control method as claimed in claim 6, is characterized in that, separately comprises:
According to this pulse-width modulation signal and this current limliting signal, and this current sensing signal is set to one first capacitor charging; And
Produce a current signal according to a magnitude of voltage of this first electric capacity, make this difference between this current signal and this current sensing signal of the 4th time point and this current sensing signal of this second time point present proportionate relationship.
10. control method as claimed in claim 9, is characterized in that, separately comprises:
According to this pulse-width modulation signal and one time of delay signal and produce a switch controlling signal, make this switch controlling signal maintain the time of effective status and this current sensing signal of the 3rd time point presents proportionate relationship; And
Use this switch controlling signal for the conducting state of one the 5th switching circuit is set, so that this current signal to be set, one the 3rd capacitor charging is produced to this power estimated signal.
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| CN201310161735.8A CN104143901B (en) | 2013-05-06 | 2013-05-06 | The control method of the control circuit and correlation of power supply changeover device |
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| CN201310161735.8A CN104143901B (en) | 2013-05-06 | 2013-05-06 | The control method of the control circuit and correlation of power supply changeover device |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN113889019A (en) * | 2021-10-18 | 2022-01-04 | 深圳市华星光电半导体显示技术有限公司 | Gamma reference voltage generation circuit, gamma voltage generation circuit and display device |
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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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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN113889019A (en) * | 2021-10-18 | 2022-01-04 | 深圳市华星光电半导体显示技术有限公司 | Gamma reference voltage generation circuit, gamma voltage generation circuit and display device |
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