CN102263501B - Control method and controller - Google Patents
Control method and controller Download PDFInfo
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- CN102263501B CN102263501B CN201010194753.2A CN201010194753A CN102263501B CN 102263501 B CN102263501 B CN 102263501B CN 201010194753 A CN201010194753 A CN 201010194753A CN 102263501 B CN102263501 B CN 102263501B
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- 238000000034 method Methods 0.000 title claims abstract description 11
- 238000001514 detection method Methods 0.000 claims abstract description 25
- 230000001939 inductive effect Effects 0.000 claims abstract description 14
- 238000004804 winding Methods 0.000 claims description 10
- 239000003990 capacitor Substances 0.000 claims description 9
- 230000008713 feedback mechanism Effects 0.000 claims description 2
- 238000005516 engineering process Methods 0.000 description 3
- 230000004224 protection Effects 0.000 description 3
- 238000006243 chemical reaction Methods 0.000 description 2
- 230000026683 transduction Effects 0.000 description 2
- 238000010361 transduction Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 1
- 238000004146 energy storage Methods 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 230000001960 triggered effect Effects 0.000 description 1
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Abstract
The controller and the control method are suitable for a power supply. The power supply includes a switch and an inductive element connected in series. The switch is turned on to increase the inductor current of the inductor element. The inductive current flowing through the inductive element is detected to generate a current detection signal. The current detection signal and an adjustment signal are summed to generate a summed signal. The summed signal is compared to a peak limit. The switch is closed when the summed signal approximately exceeds the peak limit. An on-time or duty cycle of the switch is detected, and the adjustment signal is updated accordingly.
Description
Technical field
The invention relates to overcurrent protection (over current protect ion, the OCP) method of a kind of switch type power supplying device (Switched-mode power supply, SMPS) and relevant device.
Background technology
Power supply unit is a kind of electric power controller, is used for conversion electric power, to provide power supply to electronic installation or element.For instance, Fig. 1 is a known power supply unit 60, has flyback framework (flyback topology).Bridge rectifier 62 rectifications AC power V
aC, input power V is provided
iNto transformer 64.When switch 72 short circuits (close), the first side winding L of transformer 64
penergy storage; When open circuit (open), the secondary side winding L of transformer 64
sreleasing by rectifier 66 can be to load capacitance (load capacitor) 69 to set up out-put supply V
oUT.Error amplifier (error amplifier) EA is out-put supply V relatively
oUTvoltage and target voltage V
target, and produce compensating signal V
cOM.Controller 74 is according to compensating signal V
cOMand current detection signal V
cS, with control signal V
gATEcontrol switch 72.Current detection signal V
cSreaction stream is through first side winding L
pinductive current.
Fig. 2 illustrates the controller 74 of Fig. 1.Clock generator 76 periodically makes logical block 79 opening switchs 72.Roughly current limit detection signal V of comparator 77 and 78
cSpeak value be roughly no more than a peak value limit value V
cS-LIMITwith compensating signal V
cOMvoltage in smaller value.Overcurrent protection is reached by comparator 78 and logical block 79, wishes to make current detection signal V
cSpeak value can not exceed peak value limit value V
cS-LIMIT.
But comparator 78 is found current detection signal V
cSup to peak value limit value V
cS-LIMIT, have segment signal time of delay to real closing switch 72.In this segment signal time of delay, current detection signal V
cScan raise constantly.Therefore, current detection signal V
cStend to higher than peak value limit value V
cS-LIMIT, and the voltage △ V exceeding can be along with input power V
iNvoltage different and have different results.Such difference, for instance, can make power supply unit 60 at different input power V
iNwhen voltage, have different out-put supply V
oUTpeak power output.This is beyond affordability for system designer.
Summary of the invention
The embodiment of the present invention provides a kind of control method, for a power supply unit, it includes a switch and an inductance element of series winding, this power supply unit also includes a detection resistance and is connected between this switch and a power line, an and adjusting resistance, have a first end and be connected to this switch and this detection resistance, the method includes: open this switch, increase the inductive current of this inductance element; The flow through inductive current of this inductance element of detection, to produce a current detection signal; This current detection signal and one is adjusted to signal and add up, produce one and add resultant signal; Relatively this adds resultant signal and a peak value limit value, in the time that this adds resultant signal and exceedes this peak value limit value, closes this switch; Detect an opening time or the responsibility cycle of this switch, and upgrade according to this this adjustment signal; One compensating signal is provided, reacts an output voltage of this power supply unit; When this compensating signal is during lower than a default value, stop providing this adjustment signal; One adjustment electric current is provided, this adjusting resistance of flowing through, this adjustment electric current remains unchanged in the time of this switch open; In the time that the voltage of one second end of this adjusting resistance exceeds this peak value limit value, close this switch; According to this opening time or responsibility cycle, change this adjustment electric current; Determine electric current to a capacitor charging with one first; With one second determine electric current in this opening time or responsibility cycle to this capacitor discharge; And according to and according to a control voltage, adjust this and second determine electric current and this adjustment electric current, wherein, one end of this electric capacity is connected in this first input of determining the output of electric current and this second and determining electric current, the other end ground connection of this electric capacity, wherein, this control voltage determines that this adjustment electric current and second determines electric current I
eXP, formula I
sET* T
cYCLE=I
eXP* T
oN, wherein, T
cYCLEfor the switch periods of this switch, T
oNfor the opening time of this switch, I
sETbe first to determine electric current, after a switch periods, if the left side of above-mentioned formula is greater than right side, this control voltage rises, and then has increased this adjustment electric current L and second and determine electric current I
eXP, vice versa.
The embodiment of the present invention provides a kind of controller, and for a power supply unit, a switch and an inductance element that it includes series winding, include: a logic processing device, in order to open this switch; One comparator, in the time that the voltage of a test side exceeds a peak value limit value, closes this switch; And the sternly raw device of an electric current, according to an opening time or the responsibility cycle of this switch, produce one and adjust electric current, flow to one end of this switch by this test side, and in the time of this opening time or responsibility cycle increase, this adjustment electric current reduces; Wherein, this adjustment electric current, in the time of this opening time or responsibility cycle, is certain value, wherein, this current generator includes: a control unit, when a compensating signal is during lower than a default value, stop this adjustment electric current, wherein, this compensating signal reacts an output voltage of this power supply unit; One first constant current source, to a capacitor charging; One second constant current source, in the time of this unlatching to this capacitor discharge; And a feedback path, control voltage according to one, change the electric current of this second constant current source; Wherein, this adjustment electric current is proportional to the electric current of this second constant current source, and wherein, this control voltage determines to control electric current I
cTLwith second determine electric current I
eXP, formula I
sET* T
cYCLE=I
eXP* T
oN, wherein, T
cYCLEfor the switch periods of this switch, T
oNfor the opening time of this switch, I
sETbe first to determine electric current, after a switch periods, if the left side of above-mentioned formula is greater than right side, controls voltage and rise, and then increased control electric current I
cTLand second determine electric current I
eXP, vice versa.
Brief description of the drawings
Fig. 1 is a known power supply unit.
Fig. 2 is the controller in Fig. 1.
Fig. 3 is according to a power supply unit of the invention process.
Fig. 4 is the controller in Fig. 3.
Fig. 5 has shown limits value I
cS-LIMITwith opening time T
oNrelation, and two different input power V
iNunder inductive current I
p.
Fig. 6 is exemplified with the current generator in Fig. 4.
[main element label declaration]
| 60、90 | Power supply unit |
| 62 | Bridge rectifier |
| 64 | Transformer |
| 66 | Rectifier |
| 69 | Load capacitance |
| 72 | Switch |
| 74、80 | Controller |
| 76 | Clock generator |
| 77、78 | Comparator |
| 79 | Logical block |
| 82 | Current generator |
| 84 | Current mirror |
| 86、88 | Constant current source |
| 89 | Electric capacity |
| C： LIMIT | Curve |
| CS | Detect resistance |
| EA | Error amplifier |
| FCS | Adjusting resistance |
| GM | Transduction comparator |
| I CS-LIMIT | Limits value |
| I CS-OUT | Adjust electric current |
| I CTI， | The stream of roaring |
| I SET、I EXP | Determine electric current |
| I P | Inductive current |
| L P | First side winding |
| L S | Secondary side winding |
| S 1、S 2 | Lines |
| SS | Test side |
| T ON | Opening time |
| V AC | AC power |
| V COM | Compensating signal |
| V CS | Current detection signal |
| V CS-LIMIT | Peak value limit value |
| V CTL | Control voltage |
| V FCS | Adjust signal |
| V GATE | Control signal |
| V TN | Input power |
| V OUT | Out-put supply |
| V REF | Default value |
| V Target | Target voltage |
Embodiment
Fig. 3 is that Fig. 4 illustrates the controller 80 in Fig. 3 according to a power supply unit 90 of the invention process.In Fig. 3 and Fig. 4, with label identical in Fig. 1,2 of known technology represent identical or with element, device or signal, be known technology, do not add tired stating at this.Fig. 3 and 4 is only an embodiment, implements the present invention and not must use same or analogous element, device or signal in Fig. 1 and 2.Interest field of the present invention should be read as restriction with claim.
Different with Fig. 1, in Fig. 3, between the test side SS of controller 80 and detection resistance CS, be connected with adjusting resistance FCS.Different with Fig. 2, in Fig. 4, controller 80 has current generator 82, and adjustment electric current I is provided
cS-OUT, by test side, adjusting resistance FCS and detection resistance CS flow through.The controller 80 of Fig. 4 can be implemented with an integrated circuit, and it is connected with adjusting resistance FCS's, can pass through an IC bond (pin).
By control signal V
gATE, opening time (ON time) T of current generator 82 sense switches 72
oNor responsibility cycle (Duty cycle) D, to upgrade adjustment electric current I
cS-OUT, wherein responsibility cycle D is opening time T
oNdivided by whole switch periods.Adjust electric current I
cS-OUTvalue, in the time that switch 72 is opened, large appointment maintains a constant definite value.In current generator 82, can provide a feedback mechanism, a switch periods changes once adjusts electric current I
cS-OUT, make opening time T
oNor responsibility cycle D and adjustment electric current I
cS-OUTroughly be inverse ratio.For instance, as 72 opening time of the switch T in a switch periods
oNor responsibility cycle D is while becoming large, just reduces the adjustment electric current I of next switch periods
cS-OUT.
Upgrade and adjust electric current I
cS-OUTin equivalence, upgrade the first side winding L that flows through
pinductive current I
plimits value I
cS-LIMIT, it is for triggering the inductive current value of OCP.Please also refer to Fig. 3 and Fig. 4.The condition that comparator 78 is triggered is that the voltage of test side approximates greatly peak value limit value V
cS-LIMIT, as shown in following formula (1):
V
CS-LIMIT=V
FCS+V
CS....(1)
Wherein, V
fCSwith V
cSbeing respectively adjusting resistance FCS and the cross-pressure that detects resistance CS, is respectively also an adjustment signal and a current detection signal.The voltage of test side is exactly approximately to adjust signal V
fCSand current detection signal V
cSvoltage add up.Suppose the resistance value R of adjusting resistance FCS
fCSmuch larger than the resistance value R that detects resistance CS
cS, formula (1) can approximately arrange and be:
V
CS-LIMIT=I
CS-OUT*R
FCS+I
CS-LIMIT*R
CS
I
CS-LIMIT=(V
CS-LIMIT-I
CS-OUT*R
FCS)/R
CS...(2)
Suppose adjustment electric current I
cS-OUTwith opening time T
oNinverse relation be
I
CS-OUT*T
ON=K...(3)
Wherein K is constant.Formula (2) can become
I
CS-LIMIT=(V
CS-LIMIT/R
CS)-K*R
FCS/(R
CS*T
ON)...(4)
In formula (4), K*R
fCS/ (R
cS* T
oN) can be considered as the amount of deleting, in order to reduce peak value limit value V
cS-LIMITcorresponding primary current limit value (V
cS-LIMIT/ R
cS), start ahead of time to limit inductive current I
p.Curve C in Fig. 5:
lIMITexemplified with limits value I in formula (4)
cS-LIMITwith opening time T
oNrelation.Lines S in Fig. 5
1with S
2also two different input power V have been shown
iNunder inductive current I
p, wherein lines S
1corresponding input power V
iNhigher, so opening time T
oNshorter, limits value I
cS-LIMITfor smaller I
pI.As shown in Figure 5, as long as suitably choose R
fCS, likely can allow inductive current I
ppeak value, not along with input power V
iNchange, be fixed on about primary current limit value V
cS-UMIT/ R
cS, solve the problem causing signal delay time, in addition, in above derived formula and explanation, all can replace opening time T by responsibility cycle D
oN.
Fig. 6 is exemplified with the current generator 82 in Fig. 4.Constant current source 86 provides determines electric current I
sETelectric capacity 89 is charged; Constant current source 88 provides determines electric current I
eXP, only at control signal V
gATEfor " 1 " in logic, when namely switch 72 is opened, electric capacity 89 is discharged.In the time that switch 72 is opened, control voltage V
cTL, it has determined electric current I
cTLwith determine electric current I
eXP, be maintained haply a definite value.84 of current mirrors (cu rrent mi rror) make to adjust electric current I
cS-OUTapproximately with electric current I
cTLequal proportion.From circuit analysis, Fig. 6 has realized following formula (5).
I
SET*T
CYCLE=I
EXP*T
ON...(5)
Wherein, T
cYCLEfor the switch periods of switch 72.For instance, after a switch periods, if the left side of formula (5) is greater than right side, control voltage V
cTLjust can rise, and then increase electric current I
cTLand determine electric current I
eXP.Control voltage V
cTLto determining electric current I
eXPsuch feedback path, can allow the left and right sides of formula (5) be tending towards roughly equal.Formula (5) can be derived adjustment electric current I
cS-OUTwith opening time T
oNrelation, as shown in following formula (6):
I
CS-OUT=K
1*I
CTL=K
2*I
EXP=K
3*I
SET*T
CYCLE/T
ON...(6)
If D represents with responsibility cycle, formula (6) can be rewritten as:
I
CS-OUT=K
3*I
SET/D...(7)
Wherein, determine electric current I
sETwith T
cYCLEwhile being definite value, significantly, adjust electric current I
cS-OUTjust with opening time T
oNor responsibility cycle D is approximately inversely proportional to.
Adjust electric current I
cS-OUTshould be to occur at OCP, namely power supply unit, in the time of heavy duty, just needs to produce.So transduction comparator GM can be used as a control unit, by detecting compensating signal V
cOM, determine whether to produce adjustment electric current I
cS-OUT.In Fig. 6, as compensating signal V
cOMlower than default value V
rEFtime, can be considered as underloading or no-load, adjust electric current I
cS-OUTwill stop, becoming 0, so limits value I
cS-LIMITjust can not be subject to opening time T
oNor the variation of responsibility cycle D and affecting.
In the embodiment of Fig. 4, by triggering ahead of time restriction inductive current I
p, attempt solving the problem that may cause signal delay time.System manufacturer can, by selecting a suitable external adjusting resistance FCS, determine the effect that it may reach.
Though the present invention is taking the SMPS of a flyback framework as example, the present invention also goes for the similarly SMPS such as step-down power converter, booster power transducer.
The foregoing is only preferred embodiment of the present invention, all equalizations of doing according to the claims in the present invention scope change and modify, and all should belong to covering scope of the present invention.
Claims (5)
1. a control method, for a power supply unit, it includes a switch and an inductance element of series winding, this power supply unit also includes a detection resistance and is connected between this switch and a power line, an and adjusting resistance, have a first end and be connected to this switch and this detection resistance, the method includes:
Open this switch, increase the inductive current of this inductance element;
The flow through inductive current of this inductance element of detection, to produce a current detection signal;
This current detection signal and one is adjusted to signal and add up, produce one and add resultant signal;
Relatively this adds resultant signal and a peak value limit value, in the time that this adds resultant signal and exceedes this peak value limit value, closes this switch;
Detect an opening time or the responsibility cycle of this switch, and upgrade according to this this adjustment signal;
One compensating signal is provided, reacts an output voltage of this power supply unit;
When this compensating signal is during lower than a default value, stop providing this adjustment signal;
One adjustment electric current is provided, this adjusting resistance of flowing through, this adjustment electric current remains unchanged in the time of this switch open;
In the time that the voltage of one second end of this adjusting resistance exceeds this peak value limit value, close this switch;
According to this opening time or responsibility cycle, change this adjustment electric current;
Determine electric current to a capacitor charging with one first;
With one second determine electric current in this opening time or responsibility cycle to this capacitor discharge; And
Control voltage according to one, adjust this and second determine electric current and this adjustment electric current,
Wherein, one end of this electric capacity is connected in this first input of determining the output of electric current and this second and determining electric current, the other end ground connection of this electric capacity, and wherein, this control voltage determines that this adjustment electric current and second determines electric current I
eXP, formula I
sET* T
cYCLE=I
eXP* T
oN, wherein, T
cYCLEfor the switch periods of this switch, T
oNfor the opening time of this switch, I
sETbe first to determine electric current, after a switch periods, if the left side of above-mentioned formula is greater than right side, this control voltage rises, and then has increased this adjustment electric current L and second and determine electric current I
eXP, vice versa.
2. control method according to claim 1, also includes:
In the time of this opening time or responsibility cycle increase, reduce this adjustment electric current.
3. a controller, for a power supply unit, a switch and an inductance element that it includes series winding, include:
One logic processing device, in order to open this switch;
One comparator, in the time that the voltage of a test side exceeds a peak value limit value, closes this switch; And
One current generator, according to an opening time or the responsibility cycle of this switch, produces one and adjusts electric current, flow to one end of this switch by this test side, and in the time of this opening time or responsibility cycle increase, this adjustment electric current reduces;
Wherein, this adjustment electric current, in the time of this opening time or responsibility cycle, is certain value,
Wherein, this current generator includes:
One control unit, when a compensating signal is during lower than a default value, stops this adjustment electric current, and wherein, this compensating signal reacts an output voltage of this power supply unit;
One first constant current source, to a capacitor charging;
One second constant current source, in the time of this unlatching to this capacitor discharge; And
One feedback path, according to a control voltage, changes the electric current of this second constant current source;
Wherein, this adjustment electric current is proportional to the electric current of this second constant current source,
Wherein, this control voltage determines to control electric current I
cTLwith second determine electric current I
eXP, formula I
sET* T
cYCLE=I
eXP* T
oN, wherein, T
cYCLEfor the switch periods of this switch, T
oNfor the opening time of this switch, I
sETbe first to determine electric current, after a switch periods, if the left side of above-mentioned formula is greater than right side, controls voltage and rise, and then increased control electric current I
cTLand second determine electric current I
eXP, vice versa.
4. controller according to claim 3, this power supply unit also includes:
One detects resistance, is connected between this switch and a power line; And
One adjusting resistance, is connected between this detection resistance and this test side.
5. controller according to claim 3, wherein, this current generator provides a feedback mechanism, makes this adjustment electric current and this opening time or responsibility cycle, is inverse ratio.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201010194753.2A CN102263501B (en) | 2010-05-31 | 2010-05-31 | Control method and controller |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201010194753.2A CN102263501B (en) | 2010-05-31 | 2010-05-31 | Control method and controller |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN102263501A CN102263501A (en) | 2011-11-30 |
| CN102263501B true CN102263501B (en) | 2014-10-22 |
Family
ID=45010001
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201010194753.2A Active CN102263501B (en) | 2010-05-31 | 2010-05-31 | Control method and controller |
Country Status (1)
| Country | Link |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| TWI551021B (en) * | 2015-11-25 | 2016-09-21 | 財團法人金屬工業研究發展中心 | Flyback power converter and control method thereof |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1630175A (en) * | 2003-12-19 | 2005-06-22 | 夏普株式会社 | Switching power supply apparatus and electric appliance therewith |
| CN101662223A (en) * | 2009-09-24 | 2010-03-03 | 上海导向微电子有限公司 | System and method for compensating maximum output power of switching power supply |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2010022097A (en) * | 2008-07-09 | 2010-01-28 | Panasonic Corp | Switching control circuit, semiconductor device, and switching power source apparatus |
-
2010
- 2010-05-31 CN CN201010194753.2A patent/CN102263501B/en active Active
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1630175A (en) * | 2003-12-19 | 2005-06-22 | 夏普株式会社 | Switching power supply apparatus and electric appliance therewith |
| CN101662223A (en) * | 2009-09-24 | 2010-03-03 | 上海导向微电子有限公司 | System and method for compensating maximum output power of switching power supply |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| TWI551021B (en) * | 2015-11-25 | 2016-09-21 | 財團法人金屬工業研究發展中心 | Flyback power converter and control method thereof |
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| CN102263501A (en) | 2011-11-30 |
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