CN101997437B - Integrated circuit and control method of switching power supply - Google Patents
Integrated circuit and control method of switching power supply Download PDFInfo
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- CN101997437B CN101997437B CN200910165202.0A CN200910165202A CN101997437B CN 101997437 B CN101997437 B CN 101997437B CN 200910165202 A CN200910165202 A CN 200910165202A CN 101997437 B CN101997437 B CN 101997437B
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Abstract
The invention relates to an integrated circuit and a control method of a switching power supply. The integrated circuit is used for generating a switch control signal capable of adjusting the start time so as to drive a power switch, and comprises an adjusting circuit and a limit signal generator, wherein the adjusting circuit is used for providing the switch control signal and adjusting the start time of the switch control signal according to a limit signal and a detection signal; the detection signal is related to the current flowing through the power switch; and the limit signal generator is used for sampling a reference signal when the detection signal is greater than or equal to the limit signal, and updating the value of the limit signal according to the sampling value of the reference signal.
Description
Technical field
The present invention is relevant to a kind of switched power supplier, and the sampling value of the last cycle internal reference signals of espespecially a kind of foundation is upgraded the switched power supplier of restricting signal in the current cycle.
Background technology
Good voltage conversion circuit can provide a stable output voltage and large-scale output current, make output voltage when load instantaneous variation, still can at voltage level originally, also provide fast different load currents by fast and stable, make the conversion of full blast.The common voltage conversion circuit of tradition has two kinds: switch type pressurizer (switching regulator) and linear voltage regulator (linear regulator).
Please refer to Fig. 1, Fig. 1 is the schematic diagram of a switched power supplier 100 in prior art.Switched power supplier 100 comprises a transformer 102, a power switch 104, a Circuit tuning 106, a circuit for detecting 108, and a restricting signal generator 110, can be by input voltage V
iNbe converted to output voltage V
oUT.Power switch 104 is by a switch controlling signal V
sWcontrol: when power switch 104 is opened, input voltage V
iNcan charge to the main winding of transformer 102 (primary coil), the electric current of the main winding that makes to flow through increases gradually; When power switch 104 is closed, deposit in energy in main winding and can see through secondary winding (secondary coil) to output capacitance Co charging and discharge.Circuit for detecting 108 comprises a resistance R
cs, be serially connected with power switch 104, therefore can induced flow through the electric current of power switch 104, and provide a corresponding detection signal V
cs.Restricting signal generator 110 can provide a restricting signal V
lIMIT, be used for generally defining the maximum I of the electric current of allowing the main winding of flowing through
p-MAX.Circuit tuning 106 comprises a comparator 114 and one drive circuit 116.As detection signal V
csvoltage be greater than restricting signal V
lIMITvoltage time, drive circuit 116 is just according to comparison signal V
cOMPproduce switch controlling signal V
sW, to close power switch 104.At this, the moment that power switch 104 is closed, the electric current of the power switch 104 of flowing through is I
p-MAX.
Maximum I
p-MAXshould design not with input voltage V
iNvalue change, in order to define the peak power output of this switched power supplier 100.Just, from detecting detection signal V
csbe greater than restricting signal V
lIMITtime, the time of really closing to power switch 104, there is the effect of signal propagation delay (signalpropagation delay).As restricting signal V
lIMITduring for fixed value, this effect may cause I
p-MAXalong with input voltage V
iNincrease and increase.A kind of known solution is to make restricting signal V
lIMITthe time of opening along with power switch 104 increases and increases.Higher input voltage V
iN104 opening times of lower power switch will be had, so can meet lower restricting signal V
lIMIT, as long as design is good, just can offset with the effect of signal propagation delay, obtain approximately fixing not with input voltage V
iNthe maximum I of change
p-MAX.
At switched power supplier, a kind of general known problem is called subharmonic concussion (sub-harmonic oscillation), this refers to when the work period (duty cycle) surpasses 50%, and switched power supplier may start concussion with half frequency of switching frequency.A kind of method that solves subharmonic concussion is to provide slope-compensation (slope compensation).A kind of simple slope-compensation is to make restricting signal V
lIMITthe time of opening along with power switch 104 increases and reduces, namely the work period larger, the time that power switch 104 is opened is longer, can meet lower restricting signal V
lIMIT.
By above explanation, can be found, improve the method for subharmonic concussion, just can worsen the maximum I that signal propagation delay effect causes
p-MAXthe problem of change; Vice versa.Therefore, how having solved a problem, and at least do not worsened another problem, is the target that industry is pursued.
Summary of the invention
Technical problem to be solved by this invention is to provide the control method of a kind of integrated circuit and switched power supplier, and effect that can offseting signal transmission delay also can solve subharmonic concussion simultaneously effectively.
One embodiment of the invention provide a kind of switched power supplier, and it comprises a power switch, and it operates according to tool capable of regulating open-interval one switch controlling signal; One Circuit tuning, is used for opening time of this switch controlling signal being provided and adjusting this switch controlling signal according to a restricting signal and a detection signal, and wherein this detection signal is relevant to the electric current of this power switch of flowing through; And a restricting signal generator, be used for when this detection signal is more than or equal to this restricting signal, one reference signal being sampled, and the value of upgrading this restricting signal according to the sampling value of this reference signal.
One embodiment of the invention also provide a kind of integrated circuit, be used for producing capable of regulating open-interval one switch controlling signal to drive a power switch, this integrated circuit comprises a Circuit tuning, be used for the opening time that this switch controlling signal is provided and adjusts this switch controlling signal according to a restricting signal and a detection signal, wherein this detection signal is relevant to the electric current of this power switch of flowing through; And a restricting signal generator, be used for when this detection signal is more than or equal to this restricting signal, one reference signal being sampled, and the value of upgrading this restricting signal according to the sampling value of this reference signal.
One embodiment of the invention also provide a kind of control method of switched power supplier, and it comprises according to a switch controlling signal controls the unlatching of a power switch or closes; Electric current according to this power switch of flowing through provides a detection signal; According to this detection signal and a restricting signal, adjust the opening time of this switch controlling signal; When this detection signal is more than or equal to this restricting signal, a reference signal is sampled; And the value of upgrading this restricting signal according to the sampling value of this reference signal.
Switched power supplier of the present invention upgrades restricting signal in the current cycle according to the sampling value of last cycle internal reference signals, has offset the effect of signal propagation delay, has also effectively solved subharmonic concussion simultaneously.
Accompanying drawing explanation
Fig. 1 is the schematic diagram of a switched power supplier in prior art;
Fig. 2 is the schematic diagram of a switched power supplier in the present invention;
Fig. 3 is the schematic diagram of sample-and-hold circuit in first embodiment of the invention;
Fig. 4 is the schematic diagram of sample-and-hold circuit in second embodiment of the invention;
Fig. 5 is the oscillogram of reference signal in the embodiment of the present invention;
Fig. 6 is the schematic diagram of a clamped circuit in the embodiment of the present invention;
Fig. 7 is the sequential chart while driving switched power supplier with implementation method of the present invention.
[main element symbol description]
60: pulse generator 102,602: transformer
70: reverser 104,604: power switch
612: clamped circuit 106,606: Circuit tuning
618: reference signal generator 108,608: circuit for detecting
700: sample-and-hold circuit 110,610: restricting signal generator
R
cS: resistance 114,614: comparator
SW1, SW2: switch 116,616: drive circuit
D1, D2: diode
Co, C1, C2, Cx: electric capacity
100,600: switched power supplier
Embodiment
Please refer to Fig. 2, the schematic diagram that Fig. 2 is the switched power supplier 600 implemented according to the present invention.Switched power supplier 600 comprises a transformer 602, a power switch 604, a Circuit tuning 606, a circuit for detecting 608, and a restricting signal generator 610, can be by input voltage V
iNbe converted to output voltage V
oUT.Power switch 604 is by a switch controlling signal V
sWcontrol: when power switch 604 is opened, input voltage V
iNcan charge to the main winding of transformer 602, the electric current of the main winding that makes to flow through increases gradually; When power switch 604 is closed, the energy of depositing in main winding can charge and discharge output capacitance Co through secondary winding.Circuit for detecting 608 comprises a resistance R
cs, be serially connected with power switch 604, therefore can induced flow through the electric current of power switch 604, and provide a corresponding detection signal V
cs.Restricting signal generator 610 comprises a reference signal generator 618, a sample-and-hold circuit 700 and a clamped circuit 612, and a restricting signal V can be provided
lIMIT: reference signal generator 618 can provide a reference signal V
rEF(t), reference signal V
rEF(t) value is t and becoming in time; Sample-and-hold circuit 700 is according to switch controlling signal V
sWvoltage quasi position come reference signal V
rEF(t) sample, then the restricting signal V using sampling value as next cycle
lIMIT; Clamped circuit 612 effects are restricting signal V '
lIMITmaximum maintain a predetermined value, avoid surpassing the system upper limit.Therefore, as restricting signal V '
lIMITwhile not surpassing this predetermined value, the restricting signal V ' of clamped circuit 612 outputs
lIMITrestricting signal V with sample-and-hold circuit 700 outputs
lIMITthe identical value of tool; As restricting signal V '
lIMITwhile surpassing this predetermined value, restricting signal V
lIMITvalue can maintain this predetermined value.Circuit tuning 606 comprises a comparator 614 and one drive circuit 616: comparator 614 receives restricting signal V at positive input terminal
lIMIT, at negative input end, receive detection signal V
cs, and according to restricting signal V
lIMITwith detection signal V
cssize at output, provide a corresponding comparison signal V
cOMP; Drive circuit 616 can be according to comparison signal V
cOMPproduce switch controlling signal V
sWresponsibility cycle, power ratio control switch 604 according to this.
Please refer to Fig. 3, Fig. 3 is the schematic diagram of sample-and-hold circuit 700 in first embodiment of the invention.In the embodiment shown in fig. 3, sample-and-hold circuit 700 comprises two interrupteur SW 1 and SW2, two capacitor C 1 and C2 and a reverser 70.See through reverser 70, interrupteur SW 1 and SW2 can be according to switch controlling signal V
sWcurrent potential height with complimentary fashion, operate: as switch controlling signal V
sWduring tool high potential, interrupteur SW 1 is for opening (short circuit) interrupteur SW 2 for closing (open circuit); As switch controlling signal V
sWduring tool electronegative potential, interrupteur SW 1 is for closing (open circuit) interrupteur SW 2 for opening (short circuit).
According to embodiments of the invention, the restricting signal V of an all corresponding other definite value of its each cycle
lIMIT, for instance for period T 1～Tn, restricting signal V
lIMITvalue by V1～Vn, represented respectively, and detection signal V
cSthe time point that reaches restricting signal V1～Vn in period T 1～Tn is represented by t1～tn respectively.With two adjacent period T 1 and T2, explain, after entering period T 1, at detection signal V
cSdo not surpass in the situation of restricting signal V1 switch controlling signal V
sWmaintain high potential, so interrupteur SW 1 is for unlatching interrupteur SW 2 is for closing, now reference signal V
rEF(t) can charge to capacitor C 1, that is keep reference signal V through the memory end N1 of capacitor C 1
rEF(t) current potential; At detection signal V
cSat time point t1, reach after restricting signal V1 switch controlling signal V
sWcan switch to electronegative potential, therefore interrupteur SW 1 is for closing interrupteur SW 2 for opening, the electric charge being now stored in capacitor C 1 can be sent to capacitor C 2, and according to capacitance voltage distribution principle, the current potential of the memory end N2 of capacitor C 2 is renewable, and as the foundation of upgrading the restricting signal V2 of next period T 2.
In other words, in a specific period, as detection signal V
cSat a particular point in time, reach the restricting signal V of this specific period
lIMITtime, the present invention at this particular point in time to reference signal V
rEF(t) sample, and the reference signal V that this particular point in time is sampled to
rEF(t) upgrade the restricting signal V in this cycle
lIMIT, as the restricting signal V in next cycle
lIMIT, then see through the corresponding restricting signal V ' of clamped circuit 612 output
lIMIT.
Please refer to Fig. 4, Fig. 4 is the schematic diagram of sample-and-hold circuit 700 in second embodiment of the invention.In the embodiment shown in fig. 4, sample-and-hold circuit 700 comprises interrupteur SW 2 and a pulse generator (pulse generator) 60.Interrupteur SW 2 can operate according to the pulse signal of pulse generator 60 outputs.The memory end N2 that second embodiment of the invention sees through capacitor C 2 keeps reference signal V
rEF(t) current potential, and utilize the unlatching of interrupteur SW 2 to upgrade the current potential that N2 is held in memory, and as the foundation of upgrading the restricting signal in next cycle.
Please refer to Fig. 5, Fig. 5 is reference signal V in the embodiment of the present invention
rEF(t) oscillogram.Reference signal V
rEF(t) be time-varying cyclical signal, and at switch controlling signal V
sWduring tool high potential, at least comprise a rising section.Triangular signal shown in Fig. 5 and ramp signal are only reference signal V of the present invention
rEF(t) embodiment, does not limit category of the present invention.In addition, the reference signal generator 618 in the embodiment of the present invention also can be the oscillator of drive circuit 616 inside.
Please refer to Fig. 6, Fig. 6 is the schematic diagram of clamped circuit 612 in the embodiment of the present invention.Clamped circuit 612 shown in Fig. 6 comprises two diode D1, D2 and a capacitor C x.Diode D1 and D2 are serially connected with voltage V
maxand V
minbetween, clamped circuit 612 can maintain a preset range by the value of restricting signal, avoids surpassing the system upper limit.Shown in Fig. 6, be only the embodiment of clamped circuit 612 of the present invention, do not limit category of the present invention.
According to embodiments of the invention, in different cycles, provide the restricting signal V of different value
lIMIT, the restricting signal V in each cycle
lIMITby switch controlling signal V in the last cycle
sWupgrade decision, that is work as detection signal V within each cycle
cSreach the restricting signal V in this cycle
lIMITtime, the present invention can be to reference signal V
rEF(t) sample, then by sampling value the restricting signal V as next cycle
lIMIT, as shown in Figure 7.Fig. 7 shows the sequential chart while driving switched power supplier with implementation method of the present invention.For instance, for period T 1～T5, restricting signal V
lIMITvalue by V1～V5, represented respectively, and detection signal V
cSthe time point that reaches restricting signal V1～V5 in period T 1～Tn is represented by t1～t5 respectively.In the present embodiment, V
rEF(t) be a ramp signal, therefore the restricting signal V to its sampling
lIMITcan be sampled to higher magnitude of voltage along with the time increase of power switch 604 unlatchings.In other words, higher input voltage V
iN604 opening times of shorter power switch will be had, so can meet lower restricting signal V
lIMIT, effect that therefore can offseting signal transmission delay, obtains approximately fixing not with input voltage V
iNthe maximum I of change
p-MAX.
In period T 1, start, power switch 604 is for opening, as detection signal V
cSat time t1, rise to the rough V of equaling
rEF(t1) time, power switch 604 can be closed, and restricting signal generator 610 can be to V immediately
rEF(t) sampling, so restricting signal V
lIMITvalue V1 be V
rEF(t1), now main winding stops charging, and is discharged by secondary winding, shown in dotted line.When period T 2 starts, power switch 604 is unlocked again, because of last discharge time in cycle too short, energy does not discharge completely, main winding also has suitable energy, therefore after power switch 604 unlatchings, detection signal V
cSnot by no-voltage, started to rise, as shown in Figure 7, as detection signal V
cSat time t2, rise to roughly while equaling restricting signal V2 that the last cycle is sampled to, power switch 604 can be closed, and now restricting signal generator 610 can be to V
rEF(t) sampling, so restricting signal V
lIMITvalue V2 be V
rEF(t2).The rest may be inferred, and the present invention can be at each cycle fine setting restricting signal V
lIMITcan make it converge to gradually certain value (for example V4=V5), even if V occurs input voltage
iNchange, restricting signal V
lIMITalso will settle out rapidly thereupon changing with renewal.
In addition, the present invention also can solve subharmonic concussion effectively.As shown in Figure 7, when occurring while surpassing 50% the work period, in second round, t2 samples and the restricting signal V that upgrades
lIMITtherefore will reduce rapidly, and the work period just can be down to rational scope and avoid subharmonic concussion to occur during the next cycle (period 3), and therefore can maintain stable output.
The foregoing is only preferred embodiment of the present invention, all equalizations of doing according to the claims in the present invention change and modify, and all should belong to covering scope of the present invention.
Claims (6)
1. an integrated circuit, is characterized in that, is used for producing capable of regulating open-interval one switch controlling signal to drive a power switch, and this integrated circuit comprises:
One Circuit tuning, is used for opening time of this switch controlling signal being provided and adjusting this switch controlling signal according to a restricting signal and a detection signal, and wherein this detection signal is relevant to the electric current of this power switch of flowing through; And
One restricting signal generator, is used for when this detection signal is more than or equal to this restricting signal, one reference signal being sampled, and the value of upgrading this restricting signal according to the sampling value of this reference signal, and this restricting signal generator also comprises:
One reference signal generator, is used to provide this reference signal; And
One sample-and-hold circuit, is used to provide this restricting signal, comprises:
One first switch, is controlled by this switch controlling signal; And
One first electric capacity, it comprises one first memory end, is used for seeing through this first switch and keeps this reference signal transmitting from this reference signal generator.
2. integrated circuit according to claim 1, is characterized in that, this sample-and-hold circuit also comprises:
One second switch, is controlled by this switch controlling signal, wherein this first and this second switch with complimentary fashion, operate; And
One second electric capacity, it comprises one second memory end, is used for seeing through this second switch and keeps this reference signal transmitting from this first electric capacity.
3. integrated circuit according to claim 1, is characterized in that, this restricting signal generator also comprises:
One clamped circuit, is used for the value of this restricting signal to be limited in a preset range.
4. integrated circuit according to claim 1, is characterized in that, within this opening time, this reference signal at least comprises a rising section.
5. integrated circuit according to claim 1, is characterized in that, also comprises:
One circuit for detecting, the electric current that is used for detecting this power switch of flowing through is to produce this detection signal.
6. integrated circuit according to claim 1, is characterized in that, this Circuit tuning comprises:
One comparator, is used for the relatively value of this restricting signal and this detection signal, and produces according to this corresponding comparison signal; And
One drive circuit, is used for adjusting according to this comparison signal the responsibility cycle of this switch controlling signal.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN200910165202.0A CN101997437B (en) | 2009-08-13 | 2009-08-13 | Integrated circuit and control method of switching power supply |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN200910165202.0A CN101997437B (en) | 2009-08-13 | 2009-08-13 | Integrated circuit and control method of switching power supply |
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| Publication Number | Publication Date |
|---|---|
| CN101997437A CN101997437A (en) | 2011-03-30 |
| CN101997437B true CN101997437B (en) | 2014-02-19 |
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|---|---|---|---|
| CN200910165202.0A Active CN101997437B (en) | 2009-08-13 | 2009-08-13 | Integrated circuit and control method of switching power supply |
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1198376C (en) * | 1999-02-23 | 2005-04-20 | 松下电器产业株式会社 | Switching regulator, DC/DC converter, and LSI system with switching regulator |
| CN1610229A (en) * | 2003-10-21 | 2005-04-27 | 罗姆股份有限公司 | Constant-voltage power supply unit |
| CN101388605A (en) * | 2007-09-11 | 2009-03-18 | 株式会社理光 | Switching regulator |
-
2009
- 2009-08-13 CN CN200910165202.0A patent/CN101997437B/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1198376C (en) * | 1999-02-23 | 2005-04-20 | 松下电器产业株式会社 | Switching regulator, DC/DC converter, and LSI system with switching regulator |
| CN1610229A (en) * | 2003-10-21 | 2005-04-27 | 罗姆股份有限公司 | Constant-voltage power supply unit |
| CN101388605A (en) * | 2007-09-11 | 2009-03-18 | 株式会社理光 | Switching regulator |
Non-Patent Citations (1)
| Title |
|---|
| JP特开2009-33883A 2009.02.12 |
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| CN101997437A (en) | 2011-03-30 |
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