CN1862935B - Output power compensating method and switching controller - Google Patents
Output power compensating method and switching controller Download PDFInfo
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- CN1862935B CN1862935B CN2005100701746A CN200510070174A CN1862935B CN 1862935 B CN1862935 B CN 1862935B CN 2005100701746 A CN2005100701746 A CN 2005100701746A CN 200510070174 A CN200510070174 A CN 200510070174A CN 1862935 B CN1862935 B CN 1862935B
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Abstract
The invention discloses the method of output power compensation of the power supply server and the switch controller, the one wave generator is used to connect the oscillator, the sawtooth wave signalis receipted to output the period three segment limiting signal; the period three segment limiting signal is send to the comparing unit. The comparing unit receives the one current measuring signal and the said period limiting signal, then it can be used to output one resetting signal; the one synchronous signal output unit connects to the said the comparing unit, the oscillator and the one powerswitch, the reset signal and the one pulse signal is recepted, the pulse signal is in-phase to output the one driving signal to the power switch, so the output power compensation of the power supplie r during the high, the low output voltage can be realized.
Description
Technical field
The present invention is relevant for a kind of method and switching control device of output power back off, especially refer to that a kind of three sections restricting signals of periodicity that utilize output in power supply unit come and the current detection signal of the obtaining computing of making comparisons, as the method and the switching control device thereof of output power back off under the high and low input voltage of power supply unit.
Background technology
Pulse-width modulation PWM is a known technology, is used for controlling and the stable power output of adjusting power supply unit.Power supply unit must provide various defencive functions, as overvoltage, overcurrent and overpower protection.Overcurrent and overpower protection are used for protecting power supply unit and peripheral circuit, to avoid causing nonvolatil injury.And in the overpower protection, the function of design output power back off has identical overload protection point as power supply unit under high and low input voltage.
Please refer to Fig. 1, be known power supply unit circuit diagram.Power supply unit uses a PWM controller U
1Come power controlling switch Q
1Switching.One detects resistance R
SWith power switch Q
1Be connected in series, be used for obtaining and flow through power switch Q
1Primary side switch current I
P, this detects resistance R
SResistance value in order to the decision power supply unit peak power output.This primary side switch current I
PFlow through the detection resistance R
S, and detecting resistance R
SLast generation one current detection signal V
CSPWM controller U
1A current detecting end VS be connected in this detection resistance R
S, receive this current detection signal V
CS, and by a Power Limitation comparator 130 and a max power constraint voltage V
MCompare computing, if current detection signal V
CSGreater than max power constraint voltage V
M, PWM controller U
1Drive signal V will periodically stop using
PWMOutput, and then the restriction and the decision power supply unit peak power output.
Multiple with reference to figure 1, as power switch Q
1During conducting, be stored in transformer T
1Energy ε on the inductance can be expressed as:
Flow through transformer T
1Primary side switch current I
PCan be expressed as:
Peak power output P can be expressed as:
This I wherein
PWith L
PBe expressed as transformer T respectively
1Primary side switch current and primary side inductance value; t
OnBe power switch Q
1During conducting, drive signal V
PWMON time; T
SBe drive signal V
PWMSwitching cycle.From top formula (2) as can be known, input voltage V
INSize can influence transformer T
1The primary side switch current I that primary side is set up
P, it is fast that higher input voltage is then set up speed, and it is slow that lower input voltage is then set up speed.This current detection signal V
CSWith this max power constraint voltage V
MThe computing of making comparisons is in order to the peak power output P of restriction with the decision power supply unit.
Because above-mentioned formula (3) can be learnt the size of power supply unit power output P and power switch Q
1ON time t
OnWith input voltage V
INRelevant.And when considering safety (safety), the actual input voltage V of power supply unit
INScope by 90Vac to 264Vac, and high and low input voltage between the difference of several times is often arranged.Yet, can automatically adjust ON time t by the feedback control loop of power supply unit
On, and make the power output P value of being maintained fixed.That is to say, as current detection signal V
CSBe higher than max power constraint voltage V
MThe time, maximum ON time will be restricted this moment, and reach limiting transformer T
1Primary side switch current I
P
Cooperate Fig. 1, please refer to Fig. 2, for the known propagation delay time causes the power output under the high and low input voltage to limit the different schematic diagram of (not compensating) accurate potential difference.Known employed Power Limitation is utilized max power constraint voltage V usually
M, for example the voltage quasi position of 1V come with current detecting end VS on current detection signal V
CSMake comparisons, if the current detection signal V on the current detecting end VS
CSGreater than 1V, this PWM controller U then
1To stop output drive signal V in output OUT
PWMTo this power switch Q
1, in order to the peak power output P of restriction with the decision power supply unit.
Yet peak power output also is subjected to PWM controller U
1Propagation delay time t
dInfluence-.Multiple with reference to figure 2, power supply unit is at fixing max power constraint voltage V
MWhen working, high input voltage can produce the steeper current detection signal V of slope down,
CS, HVWith lasting ON time t
On1Short drive signal V
PWM, HVMoreover, when working, low input can produce the slow current detection signal V of slope
CS, LVWith lasting ON time t
On2Long drive signal V
PWM, LVIn fact, as current detection signal V
CSBe higher than max power constraint voltage V
MMoment, this PWM controller U
1Drive signal V
PWMCan be through one section propagation delay time t
dAfter just can end.At this propagation delay time t
dIn, power switch Q
1Continue conducting, and will continue transmitted power.Therefore, Shi Ji drive signal V
PWMON time t
OnEqual t
On+ t
d, and no matter be under high and low input voltage, in identical power supply unit, its propagation delay time t
dSize be identical.
So power supply unit under high input voltage, actual Power Limitation voltage V
M, HVPower Limitation voltage V when understanding than low input
M, LVHeight makes power supply unit can cause the very big difference of power output when high and low input voltage.And actual power output P is shown below:
Compare aforesaid equation (3) and (4), because PWM controller U
1Inner propagation delay time t
dWill make exciting curent many (V than theoretical value
IN/ L
P) * t
d, therefore, bigger Power Limitation voltage in the time of when high input voltage, will having with respect to low input.Though should propagation delay time t
dVery short, usually between the scope of 200ns to 350ns, and under the higher switching frequency, this propagation delay time t
dTo the more shape aggravation of power output difference that high and low input voltage caused.
Summary of the invention
In view of this, the purpose of this invention is to provide a kind of method and switching control device that is used in the output power back off in the power supply unit, in power supply unit, utilize periodically three sections restricting signals to come and the current detection signals of the obtaining computing of making comparisons, and then reach the compensation of power supply unit power output under high and low input voltage.
The switching control device of output power back off of the present invention is used in the power supply unit, detects the primary side switch current that resistance extracts the power switch of flowing through by one, as the change action of this power switch of control.Switching control device uses an oscillator to connect a waveform generator, and this oscillator is exported a sawtooth signal and a pulse wave signal, and transmits sawtooth signal to this waveform generator.This waveform generator converts sawtooth signal the three sections restricting signal outputs of to one-period property; One comparing unit is connected in this detection resistance and this waveform generator, receives three sections restricting signals of a current detection signal and this periodicity, in order to export a reset signal; An and synchronous signal output unit, be connected in this comparing unit, this oscillator and this power switch, receive this reset signal and this pulse wave signal, and this pulse wave signal arrives this power switch to export a drive signal synchronously, as the compensation of power output under the high and low input voltage of power supply unit.
The present invention is used in the method for output power back off in the power supply unit, is used in the power supply unit, and this step includes: extract a current detection signal; One or three sections restricting signals are provided, and these three sections restricting signals comprise a voltage rise limitation signal, a voltage limit signal and a voltage decline restricting signal; This current detection signal of comparison operation and this three sections restricting signals, wherein, when this current detection signal was higher than this voltage rise limitation signal or voltage limit signal or voltage decline restricting signal, this power supply unit can be exported by power-limiting, as the compensation of power output.
So, the current detection signal V of power supply unit when high and low input voltage
CS, can and the comparison operation of voltage rise limitation signal, as power supply unit under high and low input voltage, the compensation of different output power.
Simultaneously, the present invention utilizes waveform generator that the voltage limit signal is provided, and limits the maximum power of power supply unit.And, the present invention utilizes waveform generator that voltage decline restricting signal is provided, limit power supply unit in the maximum power of crossing low input, to reduce power supply unit in that to spend the following work period that is produced drive signal of low input excessive and cause the output overpower.
Being noted that above general introduction and ensuing detailed description are all exemplary in nature, is in order to further specify claim of the present invention.And about other purpose of the present invention and advantage, will be set forth in follow-up explanation and accompanying drawing.
Description of drawings:
Fig. 1 is known power supply unit circuit diagram;
Fig. 2 causes the power output under the high low input to limit the different schematic diagram of accurate potential difference for known transmission time of delay;
Fig. 3 is used in the circuit diagram of power supply unit for the present invention;
The waveform generator internal circuit schematic diagram that Fig. 4 uses for the present invention;
The inner waveform schematic diagram of waveform generator that Fig. 5 uses for the present invention;
Another block schematic diagram of waveform generator that Fig. 6 uses for the present invention.
Symbol description among the figure:
The known technology label:
U
1PWM controller Q
1Power switch
T
1Transformer R
SDetect resistance
Label of the present invention:
Q
1Power switch T
1Transformer
R
SDetect resistance 50 oscillators
60 waveform generators
61 first voltage-to-current converting units
62 second voltage-to-current converting units
601,602,603,604,605,606 transistors
608 mnemons
609 digital-analog convertors
200 comparing units
270 synchronizing signal output units, 230 power comparators
240 pulse width modulation controlled unit, 250 logical circuits
Embodiment
Please refer to Fig. 3, be used in the circuit diagram of power supply unit for the present invention.The present invention has the switching control device of output power back off, is used in the power supply unit, and power supply unit uses switching control device of the present invention to come power controlling switch Q
1To transformer T
1Switching.Simultaneously, one detect resistance R
SWith power switch Q
1Be connected in series, be used for obtaining and flow through power switch Q
1Primary side switch current I
P, and produce a current detection signal V
CSSwitching control device of the present invention is by detecting resistance R
SObtain current detection signal V
CS, after computing and then control this power switch Q
1Change action.
The present invention utilizes an oscillator 50 to connect a waveform generator 60, oscillator 50 outputs one sawtooth signal V
SAWWith a pulse wave signal PLS, and transmit sawtooth signal V
SAWTo this waveform generator 60.This waveform generator 60 receives this sawtooth signal V
SAW, in order to three sections restricting signal V of output one-period property
LMTUse a comparing unit 200 simultaneously, be connected in this detection resistance R
SWith this waveform generator 60, received current detection signal V
CSWith three sections restricting signal V of this periodicity
LMT, in order to export a reset signal RST; And a synchronous signal output unit 270, be connected in this comparing unit 200, this oscillator 50 and this power switch Q
1, receive this reset signal RST and this pulse wave signal PLS, export a drive signal V in order to synchronous this pulse wave signal PLS
PWMTo this power switch Q
1
Multiple in one embodiment of this invention, this comparing unit 200 is a power comparator 230 with reference to figure 3, and the one anode is connected in these waveform generator 60, one negative terminals and is connected in this detection resistance R
S, an output is connected in this synchronizing signal output unit 270.In this embodiment, the present invention utilizes three sections restricting signal V of these power comparator 230 receiving cycles
LMTWith this current detection signal V
CS, and will compare computing, export this control enable signal V
OC(being reset signal RST) is to this synchronizing signal output unit 270.
Multiple with reference to figure 3, in another embodiment of the present invention, this comparing unit 200 further is connected to a pressure feedback port FB of power supply unit, in order to extract a feedback voltage signal V
FBWherein this comparing unit 200 more includes except having the power comparator 230 described in the embodiment of front: a pulse width modulation controlled unit 240 is connected in negative terminal, this detection resistance R of this power comparator 230
SAnd this pressure feedback port FB, receive this current detection signal V
CSWith this feedback voltage signal V
FB, output one modulation signal V after inner comparison operation
OPOne logical circuit 250 is connected to this power comparator 230, this pulse width modulation controlled unit 240 and this synchronizing signal output unit 270, receives this control enable signal V
OCWith this modulation signal V
OP, RST arrives this synchronizing signal output unit 270 in order to the output reset signal.In this embodiment, the present invention utilizes logical circuit 250 output reset signal RST to this synchronizing signal output unit 270, and this synchronizing signal output unit 270 is this pulse wave signal PLS synchronously, and output drive signal V
PWMTo this power switch Q
1, to carry out Switch Control.
Cooperate Fig. 3, please refer to Fig. 4, be waveform generator internal circuit schematic diagram of the present invention.Waveform generator 60 includes one first voltage-to-current converting unit 61 and is connected to this oscillator 50, receives sawtooth signal V
SAW, and with sawtooth signal V
SAWThe magnitude of voltage equal proportion convert a sawtooth current I to
SAW, can be expressed as:
R wherein
AIt is the resistance value of the first voltage-to-current converting unit 61.One first current mirror is connected to the first voltage-to-current converting unit 61, receives this sawtooth current I
SAW, this first current mirror is made up of a first transistor 601 and a transistor seconds 602.The first transistor 601 is connected with the grid of transistor seconds 602, and the drain electrode of the first transistor 601 is connected to its grid.The first voltage-to-current converting unit, 61 output sawtooth current I
SAWFlow into the drain electrode of the first transistor 601, and produce one first reflection electric current I at the drain electrode reflection of transistor seconds 602
1, its value can be obtained by following formula.
I
1＝N
1×I
SAW (6)
N wherein
1It is the reflection ratio of first current mirror.The first transistor 601 also is connected with the source electrode of transistor seconds 602, and is connected to a restriction current source I again
TTherefore, the first reflection electric current I of first current mirror output
1Lowest high-current value by restriction current source I
TLimit.
N
1×I
SAW≤I
T (7)
I
REF＝V
REF/R
B (8)
R wherein
BIt is the resistance value of the second voltage-to-current converting unit 62.One second current mirror is connected to the second voltage-to-current converting unit 62, receives this reference current I
REF, second current mirror is made up of one the 3rd transistor 603 and one the 4th transistor 604.The source electrode of the 3rd transistor 603 and the 4th transistor 604 is connected to earth terminal GND, and the 3rd transistor 603 is connected with the grid of the 4th transistor 604.The drain electrode of the 3rd transistor 603 is connected to its grid.The reference current I of the second voltage-to-current converting unit, 62 outputs
REFFlow into the drain electrode of the 3rd transistor 603, and produce one second reflection electric current I at the drain electrode reflection of the 4th transistor 604
2, its value can be obtained by following formula.
I
2＝N
2×I
REF (9)
N wherein
2It is the reflection ratio of second current mirror.
One the 5th transistor 605 and one the 6th transistor 606 are formed one the 3rd current mirror.The source electrode of the 5th transistor 605 and the 6th transistor 606 is connected to a supply voltage V
CCThe 5th transistor 605 is connected with the grid of the 6th transistor 606, and the drain electrode of the 5th transistor 605 is connected to its grid.The first reflection electric current I
1With the second reflection electric current I
2Flow into the drain electrode of the 5th transistor 605, and produce a Power Limitation electric current I at the drain electrode reflection of the 6th transistor 606
LMTThis Power Limitation electric current I
LMTIts value can be obtained by following formula.
I
LMT＝N
3×(I
1+I
2) (10)
N wherein
3It is the reflection ratio of the 3rd current mirror.This Power Limitation electric current I
LMTFlow through a Power Limitation resistance R
LMT, to produce three sections restricting signal V of this periodicity
LMT, shown in equation (11):
V
LMT＝I
LMT×R
LMT (11)
Please refer to Fig. 5, be waveform generator internal circuit waveform schematic diagram of the present invention.Cooperate aforementioned formula (5) to formula (7), can know the first reflection electric current I
1By sawtooth current I
SAWReflection ratio N according to first current mirror
1The generation of videoing is therefore in time T
0-T
1During this time, the first reflection electric current I
1With sawtooth current I
SAWWaveform identical with slope.But in time T
1-T
2During this time, sawtooth current I
SAWContinue to increase, and the first reflection electric current I
1Be subject to restriction current source I
T, make the reflection electric current I of winning
1Be stabilized in a fixing potential value I
ThBy the time time T
2The time, the first reflection electric current I
1Just recover again along with sawtooth current I
SAWReflection ratio N with first current mirror
1Reflection produces.So, the first reflection electric current I
1The periodicity output waveform form the waveform output kenel of syllogic.
Moreover, cooperate aforementioned formula (10), the Power Limitation electric current I
LMTBy the first reflection electric current I
1With the second reflection electric current I
2Summation, and with the reflection ratio N of the 3rd current mirror
3Reflection produces.The second reflection electric current I
2With the first reflection electric current I
1Current potential draw high, draw high the reflection of first behind current potential electric current I
1Again with the reflection ratio N of the 3rd current mirror
3Reflection produces the Power Limitation electric current I
LMTSo, the Power Limitation electric current I
LMTIts waveform also is the kenel that presents the output of syllogic waveform.And cooperate aforementioned formula (11), this Power Limitation electric current I
LMTFlow through the Power Limitation resistance R
LMT, to produce three sections restricting signal V of this periodicity
LMT
The present invention utilizes periodically three sections restricting signal V of waveform generator 60 outputs especially
LMT, be used for and current detection signal V
CSThe computing of making comparisons.At three sections restricting signal V of periodicity
LMTA signal period in, three sections restricting signal V periodically
LMTForm by a voltage rise limitation signal, a voltage limit signal and a voltage decline restricting signal.
Power supply unit can feedback be obtained the higher current detection signal V of slope down in high input voltage
CS, HV, obtain the lower current detection signal V of slope in the next feedback of low input
CS, LVNo matter power supply unit is in high or low input voltage (actual input voltage V
INScope by 90Vac to 264Vac), current detection signal all can with three sections restricting signal V periodically
LMTThe computing of making comparisons of voltage rise limitation signal.Power supply unit in high input voltage following the higher current detection signal V of the slope that produces
CS, HVCan push up periodically three sections restricting signal V very soon
LMTVoltage rise limitation signal and with the computing of making comparisons, and than low input following the lower current detection signal V of the slope that produces
CS, LVCan slowly push up periodically three sections restricting signal V
LMTVoltage rise limitation signal and with the computing of making comparisons.
In fact, when high input voltage following the higher current detection signal V of the slope that produces
CS, HVOr low input following the lower current detection signal V of the slope that produces
CS, LVBe higher than periodically three sections restricting signal V
LMTMoment of voltage rise limitation signal, the PWM controller U that power supply unit uses
2Drive signal V
PWMCan be through one section propagation delay time t
dAfter just can end.At this propagation delay time t
dIn, power switch Q
1Continue conducting, and will continue transmitted power.Simultaneously, in identical power supply unit, its propagation delay time t
dSize be identical.
In the above-mentioned explanation, because the higher current detection signal V of slope
CS, HVPush up periodically three sections restricting signal V earlier
LMTVoltage rise limitation signal, and drive signal V
PWM, HVCan be through one section propagation delay time t
dAfter just can end and the lower current detection signal V of slope
CS, LVThe slow periodically three sections restricting signal V that push up
LMTVoltage rise limitation signal, and drive signal V
PWM, LVCan magnify relatively, and through one section propagation delay time t
dAfter just can end.
Three sections restricting signal V of periodic
LMTVoltage rise limitation signal as the restriction power output of power supply unit under high and low input voltage, can allow the higher current detection signal V of slope
CS, HVOr the lower current detection signal V of slope
CS, LVAt the actual propagation delay time t that considers
dThe time, have identical actual power limit point Va.So get final product the power output difference that the offset supply supply is caused under high and low input voltage, allow power supply unit work under the different input supply voltage situation of high and low pressure, can obtain identical power output.
The composite Fig. 3 that closes with reference to figure 5, crosses (continuing to keep input voltage is lower than 70Vac below) when low when the power supply unit input voltage, and it passes through power switch Q
1Primary side switch current I
PIt is slow to set up speed, makes current feedback signal V
CS, BOSet up slowly.So when the power supply unit input voltage is crossed the current feedback signal V that is produced when hanging down
CS, BOCan be subjected to periodically three sections restricting signal V
LMTVoltage decline restricting signal limit, and then make power switch Q ahead of time
1End.
Please refer to Fig. 6, be another block schematic diagram of waveform generator of the present invention.Wherein this waveform generator 60 includes: a mnemon 608 stores many group numerical datas; And a digital-analog convertor 609, be connected in this mnemon 608, according to this pulse wave signal PLS in order to the numerical data in this mnemon 608 is converted into three sections restricting signal V of this periodicity of simulation
LMTMnemon 608 can be a read-only memory (ROM), numerical data is much organized in burning in advance, and by digital-analog convertor 609 when each this pulse wave signal PLS enters, produce the set of number data and offer three sections restricting signal V of this periodicity that digital-analog convertor 609 is converted to simulation
LMTOutput.
With reference to figure 3, illustrate that next the present invention is used in the method for output power back off in the power supply unit again, its power compensating method is for extracting a detection resistance R in the power supply unit
SOn a current detection signal V
CSThree sections restricting signals that provide one-period to have voltage rise limitation signal, voltage limit signal and voltage decline restricting signal by waveform generator 60 then, and will with this current detection signal V
CSCompare computing by a power comparator 230.So, the current detection signal V of power supply unit when high and low input voltage
CSMeeting and the comparison operation of voltage rise limitation signal make power supply unit can reach identical power output under high and low input voltage.
Simultaneously, the present invention can also utilize waveform generator 60 that three sections voltage limit signal and current detection signal V in the restricting signal are provided
CSThe computing of making comparisons is as the Power Limitation of power supply unit.And, voltage decline restricting signal and current detection signal V that the present invention can also utilize waveform generator 60 to provide
CSThe computing of making comparisons was in order to limit under the low input work period of the drive signal of power supply unit.
In the above-mentioned explanation, this current detection signal V
CSIf be higher than this voltage limit signal or voltage rise limitation signal or voltage decline restricting signal, then power supply unit can be exported by power-limiting, as the compensation of power output.
In sum, the present invention is used in the method and the switching control device of the output power back off in the power supply unit, in power supply unit, utilize three sections restricting signals of periodicity of output to come and the current detection signal of the obtaining computing of making comparisons, and then reach the compensation of power supply unit power output under high and low input voltage, be used for improving prior art under the high and low input voltage different situations of power supply unit, the power output difference that is caused and the consumption of power output.
The above, only be the detailed description and the accompanying drawing of a specific embodiment of the best of the present invention, only feature of the present invention is not limited thereto, be not in order to restriction the present invention, all scopes of the present invention should be as the criterion with described claim, all closing in the embodiment of the spirit variation similar of the present patent application claim with it, all should be contained in the category of the present invention, anyly be familiar with this skill person in the field of the invention, can think easily and variation or modify all can be encompassed within the claim of this case.
Claims (8)
1. the method for an output power back off is used in the power supply unit, it is characterized in that, this step includes:
Extract a current detection signal;
One or three sections restricting signals are provided, and these three sections restricting signals comprise a voltage rise limitation signal, a voltage limit signal and a voltage decline restricting signal;
This current detection signal of comparison operation and this three sections restricting signals, wherein, when this current detection signal was higher than this voltage rise limitation signal or voltage limit signal or voltage decline restricting signal, this power supply unit power-limiting output was as the compensation of power output.
2. the method for output power back off as claimed in claim 1 is characterized in that, in extracting the current detection signal step, this current detection signal is got by a primary side switch current that detects resistance reception power supply unit.
3. the method for output power back off as claimed in claim 1 is characterized in that, this three sections restricting signals and this current detection signal compare computing by a power comparator.
4. the switching control device with output power back off is used in the power supply unit, detects the primary side switch current that resistance extracts the power switch of flowing through by one, it is characterized in that, includes:
One oscillator is exported a sawtooth signal and a pulse wave signal;
One waveform generator is connected in this oscillator, receives this sawtooth signal, and in order to three sections restricting signals of output one-period property, three sections restricting signals of this periodicity comprise a voltage rise limitation signal, a voltage limit signal and a voltage decline restricting signal;
One comparing unit is connected in this detection resistance and this waveform generator, receives three sections restricting signals of a current detection signal and this periodicity, in order to export a reset signal; And
One synchronous signal output unit, be connected in this comparing unit, this oscillator and this power switch, receive this reset signal and this pulse wave signal, and, be synchronized with the drive signal of this pulse wave signal to this power switch in order to export one according to this reset signal and this pulse wave signal.
5. the switching control device with output power back off as claimed in claim 4, it is characterized in that this comparing unit is a power comparator, the one anode is connected in this waveform generator, one negative terminal is connected in this detection resistance, and an output is connected in this synchronizing signal output unit.
6. the switching control device with output power back off as claimed in claim 4 is characterized in that, this comparing unit is also connected to a pressure feedback port of power supply unit, includes:
One power comparator is connected in this waveform generator and this detection resistance, receives three sections restricting signals of this current detection signal and this periodicity, in order to export a control enable signal;
One pulse width modulation controlled unit is connected in this detection resistance and this pressure feedback port, receives this current detection signal and a feedback voltage signal, exports a modulation signal; And
One logical circuit is connected to this power comparator, this pulse width modulation controlled unit and this synchronizing signal output unit, receives this control enable signal and this modulation signal, in order to export this reset signal to this synchronizing signal output unit.
7. the switching control device with output power back off as claimed in claim 4 is characterized in that, this waveform generator includes:
One first voltage-to-current converting unit is connected to this oscillator, receives this sawtooth signal, and the magnitude of voltage ratio of this sawtooth signal is changed into a sawtooth current;
One first current mirror is connected to this first a voltage-to-current converting unit and a restriction current source, produces one first reflection electric current according to this sawtooth current reflection, and this first reflection current limited limits current source in this;
One second voltage-to-current converting unit is converted into reference current output with a reference voltage;
One second current mirror is connected to this first current mirror and this second voltage-to-current converting unit, produces one second reflection electric current according to this reference current;
One the 3rd current mirror is connected in this first current mirror and this second current mirror, according to the summation of this first reflection electric current and this second reflection electric current, to produce a Power Limitation electric current; And
One Power Limitation resistance is connected in the 3rd current mirror, receives this Power Limitation electric current, in order to produce three sections restricting signals of this periodicity.
8. the switching control device with output power back off as claimed in claim 4 is characterized in that, this waveform generator includes:
One mnemon stores many group numerical datas; And
One digital-analog convertor is connected in this mnemon and this oscillator, according to this pulse wave signal, in order to the numerical data in this mnemon is converted into three sections restricting signals of this periodicity of simulation.
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|---|---|---|---|
| CN2005100701746A CN1862935B (en) | 2005-05-09 | 2005-05-09 | Output power compensating method and switching controller |
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|---|---|---|---|
| CN2005100701746A CN1862935B (en) | 2005-05-09 | 2005-05-09 | Output power compensating method and switching controller |
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| JP4245066B2 (en) * | 2007-06-11 | 2009-03-25 | サンケン電気株式会社 | Multi-output switching power supply |
| CN102969697B (en) * | 2011-09-02 | 2015-07-15 | 通嘉科技股份有限公司 | Control method for overvoltage protection and control circuit used for power supply controller |
| US9921627B2 (en) | 2013-01-08 | 2018-03-20 | Semiconductor Components Industries, Llc | Control circuit for programmable power supply |
| US9564810B2 (en) | 2013-03-28 | 2017-02-07 | Infineon Technologies Austria Ag | Switched mode power supply |
| TWI663818B (en) * | 2017-08-28 | 2019-06-21 | 強弦科技股份有限公司 | Switching power supply having dynamically adjustable feedback compensation function |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1574579A (en) * | 2003-06-24 | 2005-02-02 | 罗姆股份有限公司 | Switching type dc-dc converter |
| CN1581660A (en) * | 2003-07-31 | 2005-02-16 | 罗姆股份有限公司 | DC/DC converter |
| CN2794030Y (en) * | 2005-05-10 | 2006-07-05 | 崇贸科技股份有限公司 | Switching controller with outputting powr compensation |
-
2005
- 2005-05-09 CN CN2005100701746A patent/CN1862935B/en not_active Expired - Fee Related
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1574579A (en) * | 2003-06-24 | 2005-02-02 | 罗姆股份有限公司 | Switching type dc-dc converter |
| CN1581660A (en) * | 2003-07-31 | 2005-02-16 | 罗姆股份有限公司 | DC/DC converter |
| CN2794030Y (en) * | 2005-05-10 | 2006-07-05 | 崇贸科技股份有限公司 | Switching controller with outputting powr compensation |
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| Publication number | Publication date |
|---|---|
| CN1862935A (en) | 2006-11-15 |
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