CN101604915A - Switch type power supplying device and controller with output current restriction - Google Patents
Switch type power supplying device and controller with output current restriction Download PDFInfo
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- CN101604915A CN101604915A CNA2008101112795A CN200810111279A CN101604915A CN 101604915 A CN101604915 A CN 101604915A CN A2008101112795 A CNA2008101112795 A CN A2008101112795A CN 200810111279 A CN200810111279 A CN 200810111279A CN 101604915 A CN101604915 A CN 101604915A
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Abstract
A kind of switch type power supplying device with output current restriction, utilize voltage sampling and retentive control device to obtain the corner voltage of a feedback voltage (Knee Voltage), then, corner voltage is opened radical sign computing and error computing respectively, and, according to the action of operation result power controlling switch, to reach the dual-use function of output voltage stabilizing and current limliting.
Description
Technical field
The present invention is about a kind of switch type power supplying device with output current restriction; when referring to that especially a kind of output reaches the electric current restriction; under the situation that output voltage descends, but still Be Controlled is constant for electric current, and reaches the switch type power supplying device of output current defencive function.
Background technology
On the market, the switch type power supplying device has replaced the linear stabilized power supply supply, and the former the full width that relies on a pulse is adjusted and the opening and deadline of power controlling switch, and then realizes that secondary side can produce the purpose of a burning voltage.And according to the secondary side power output, the feedback signal that output voltage and output current produced comes modulating pulse width to adjust controller to produce the pulse of suitable big or small width.
Known primary side FEEDBACK CONTROL switch type power supplying device can't reach good various output voltage modulation rate requirement, so most switch type power supplying device still directly transmits the secondary side anti feedback signal by secondary side through optical coupler and feedback regulation circuit.Therefore the use of optical coupler, feedback regulation circuit, operational amplifier and current limiting element is necessary.
Fig. 1 is a known secondary side feedback control switch formula power supply unit circuit diagram, and it is suitable for the switching power supply device of accuracy height, high-power and big output current.It utilizes operational amplifier U4A, U4B and feedback regulation device U3, the optical coupler U2 control element as Voltage Feedback and output current limiting, controls the adjuster U1 of primary side pulse duration, makes whole power supply unit reach the function of voltage stabilizing and current limliting.Though this circuit accuracy height, the relative part that is adopted is many, and the raising of cost is its shortcoming.
Fig. 2 is known primary side FEEDBACK CONTROL switch type power supplying device circuit diagram.When power switch Q1 conducting, secondary side is opposite with secondary winding polarity because of diode D3, so can't transmit energy to output V from primary side
O, this moment, energy was temporary among the transformer T1.When the voltage that detects resistance R 6 when primary side current reached reference voltage, power switch Q1 became and ends, and this moment, secondary side was because diode D3 and secondary winding polarity change forward, so the storage power of transformer T1 is delivered to output V
O, and output capacitance C4 is through the charging in cycle repeatedly and reach the effect of voltage stabilizing.Because output rectifier diode D3 pressure drop just changes with load, and the voltage of capacitor C 1 also has Different Effects with the turn-on cycle size of power switch Q1, so that can't reflect the secondary side output voltage V fully from the voltage detecting mode of primary side capacitor C 6
OVariation, so the regulation of voltage is higher, also can't provide simultaneously more stable voltage output.In addition, this known primary side FEEDBACK CONTROL switch type power supplying device circuit can't be implemented in and export when reaching the electric current restriction output voltage V
ODescend but output current still may command remain unchanged.Yet this circuit has lacked many unnecessary feedback elements compared to the secondary side feedback control switch formula power supply unit of Fig. 1, has its advantage.
Therefore, a kind of switch type power supplying device, it reaches electric current when restriction in output, output voltage descend but output current still may command remain unchanged, to reach output overcurrent protection purpose, will be that the present invention desires actively to inquire into part.
Summary of the invention
In view of this, technical problem to be solved by this invention is to provide a kind of switch type power supplying device with output current restriction, it utilizes voltage sampling and retentive control device to obtain the corner voltage of a feedback voltage (Knee Voltage), then, corner voltage is opened radical sign computing and error computing respectively, and, according to the action of operation result power controlling switch, to reach the dual-use function of output voltage stabilizing and current limliting.
The switch type power supplying device with output current restriction of first embodiment of the invention includes a transformer, a power switch, a current detector, a feedback voltage processor, and drives a radical sign generator and an on-off controller.Wherein, the elementary winding of transformer receives an input voltage, and the output of transformer induction output one output voltage, simultaneously, auxiliary winding induction output one feedback voltage of transformer.Power switch is coupled to the elementary winding of transformer.Current detector is coupled to power switch, by a primary winding current of power switch receiving transformer, and exports a current detection signal.The feedback voltage processor is coupled to the auxiliary winding of transformer, based on feedback voltage to produce a feedback voltage signal.Drive the radical sign generator and be coupled to the feedback voltage processor, open radical sign computing feedback voltage signal, and export a Current limited Control signal.On-off controller is coupled to power switch, drives radical sign generator and current detector; comparison operation current detection signal and Current limited Control signal when a guard mode; and export a drive signal to power switch according to comparative result, with the switching of power controlling switch.
With reference to first embodiment, the switch type power supplying device with output current restriction of second embodiment of the invention further comprises an error amplifier and a voltage potential adjuster.Wherein, error amplifier is coupled to feedback voltage processor and voltage potential adjuster, and simultaneously, the voltage potential adjuster is coupled between error amplifier and the on-off controller.Error amplifier comparison operation one reference voltage and feedback voltage signal, and export an error amplification signal and give the voltage potential adjuster.The voltage potential adjuster carries out the voltage potential adjustment to error amplification signal, gives on-off controller in order to export a voltage control signal.At this moment, be coupled to power switch, drive the on-off controller of radical sign generator, voltage potential adjuster and current detector, comparison operation current detection signal and Current limited Control signal or comparison operation current detection signal and voltage control signal, and export a drive signal to power switch according to comparative result, with the switching of power controlling switch.
With reference to first embodiment, the switch type power supplying device with output current restriction of third embodiment of the invention and the difference of first embodiment be in, the feedback voltage processor is coupled to Secondary winding of transformer, it is from the Secondary winding of transformer feedback voltage of sampling, to produce a feedback voltage signal based on feedback voltage.Open radical sign computing feedback voltage signal equally and drive the radical sign generator, and export a Current limited Control signal.And comparison operation current detection signal and Current limited Control signal when on-off controller is used for a guard mode equally, and export a drive signal to power switch according to comparative result, with the switching of power controlling switch.
With reference to the 3rd embodiment, the switch type power supplying device with output current restriction of fourth embodiment of the invention further comprises an error amplifier and a voltage potential adjuster.Wherein, error amplifier is coupled to the feedback voltage processor, and with the voltage potential adjuster, simultaneously, the voltage potential adjuster is coupled between error amplifier and the on-off controller.Error amplifier comparison operation one reference voltage and feedback voltage signal, and export an error amplification signal and give the voltage potential adjuster.The voltage potential adjuster carries out the voltage potential adjustment to error amplification signal, gives on-off controller in order to export a voltage control signal.At this moment, on-off controller is coupled to power switch, drives radical sign generator, voltage potential adjuster and current detector, and comparison operation current detection signal and Current limited Control signal or comparison operation current detection signal and voltage control signal, and export a drive signal to power switch according to comparative result, with the switching of power controlling switch.
To sum up, the switch type power supplying device with output current restriction provided by the invention can be when output reaches the electric current restriction, and under the situation that output voltage descends, but still Be Controlled is constant for electric current, and reaches the output current defencive function.
Above general introduction and ensuing detailed description are all exemplary in nature, are in order to further specify claim of the present invention.And relevant other objects and advantages of the present invention will be set forth in follow-up explanation and accompanying drawing.
Description of drawings
Fig. 1 is known secondary side feedback control switch formula power supply unit circuit diagram;
Fig. 2 is known primary side FEEDBACK CONTROL switch type power supplying device circuit diagram;
Fig. 3 is the switch type power supplying device schematic diagram with output current restriction of first embodiment of the invention;
Fig. 4 is the switch type power supplying device with output current restriction of second embodiment of the invention;
Fig. 5 is the switch type power supplying device with output current restriction of third embodiment of the invention;
Fig. 6 is the switch type power supplying device with output current restriction of fourth embodiment of the invention;
Fig. 7 is the on-off controller circuit box schematic diagram that first embodiment of the invention and the 3rd embodiment use;
Fig. 8 is the on-off controller circuit box schematic diagram that second embodiment of the invention and the 4th embodiment use;
Fig. 9 is a control waveform schematic diagram of the present invention;
Figure 10 is the curve synoptic diagram of output current limiting of the present invention;
Figure 11 A is the first embodiment schematic diagram of feedback voltage processor of the present invention;
Figure 11 B is the second embodiment schematic diagram of feedback voltage processor of the present invention; And
Figure 12 is the radical sign generator circuit schematic diagram of opening of the present invention.
Wherein, Reference numeral:
The adjuster U1 of primary side pulse duration
Optical coupler U2
Feedback regulation device U3
Operational amplifier U4A, U4B
Power switch Q1
Diode D3
Transformer T1
Current sense resistor R6
Output voltage V
O
Transformer T1
Power switch Q1
Current detector R6
Pulse duration is adjusted controller U1, U2
Elementary winding P1
Input voltage VIN
Secondary winding P2
Output current I
O
Auxiliary winding P3
Feedback voltage V FB
Feedback voltage signal VS
Primary winding current I
P1
Current detection signal VCS
Voltage potential adjuster 18
Error amplification signal EA
Drive radical sign generator 12
On-off controller 14, on-off controller 14a, on-off controller 14b
Noise eliminator 142
Or logical circuit 144
Current limited Control signal VCL
Drive signal DRV
Blanking signal BLANK
Reference voltage VREF1
Pressure limiting control voltage VCTL
Pick-off signal S1
Reset signal S2
Control signal S3
Supply voltage VCC
Critical voltage VREF2
Guard signal OVP
Continuity signal OSC
Noise-cancelling signal LEB
Leading edge noise voltage VP
Voltage sampling and retentive control device 10a
Reference voltage VREF3
Sampling control signal Samp
Comparator C OMP
Trigger FF1, FF2
Control switch Q3
Amplifier OP
Charging or discharging current controller Q2, Q4
Capacitor C O
Voltage sampling and retentive control device 10b
Sampling and keep single control circuit 106
Reference voltage VREF-1～VREF-n
Sampling voltage Vsamp-1～Vsamp-n
Reference voltage VREF4
Voltage VGS1, VGS2
Change-over circuit 124
Output resistance RO
Embodiment
With reference to figure 3, be the switch type power supplying device schematic diagram with output current restriction of first embodiment of the invention.Switch type power supplying device with output current restriction includes a transformer T1, a power switch Q1, a current detector R6 and a pulse duration and adjusts controller U1.Wherein, the elementary winding P1 of transformer T1 receives an input voltage VIN, and the secondary winding P2 of transformer T1 induction output one output voltage V
O, simultaneously, the auxiliary winding P3 induction output one feedback voltage V FB of transformer T1.Power switch Q1 is coupled to the elementary winding P1 of transformer T1.Current detector R6 is coupled to power switch Q1, the primary winding current I of the power switch Q1 receiving transformer T1 by conducting
P1, and export a current detection signal VCS.
Pulse duration adjustment controller U1 includes a feedback voltage processor 10, and drives a radical sign generator 12 and an on-off controller 14.Wherein, feedback voltage processor 10 is a voltage sampling and retentive control device, and feedback voltage processor 10 is coupled to the auxiliary winding P3 of transformer T1, to produce a feedback voltage signal VS based on this feedback voltage V FB.Drive radical sign generator 12 and be coupled to feedback voltage processor 10, open radical sign computing feedback voltage signal VS, and export a Current limited Control signal VCL.On-off controller 14 is coupled to power switch Q1, feedback voltage processor 10, opens radical sign generator 12 and current detector R6; comparison operation current detection signal VCS and Current limited Control signal VCL and export a drive signal DRV to power switch Q1, with the switching of power controlling switch Q1 when a guard mode according to comparative result.
In addition, on-off controller 14 also can be according to comparative result, export a blanking signal BLANK to feedback voltage processor 10, to allow the signal processing sequential of feedback voltage processor 10 after blanking signal BLANK, the influence that feedback voltage processor 10 is caused in the voltage ring (RINGING) of avoiding feedback voltage V FB, and then obtained suitable feedback voltage V FB.
Again with reference to figure 3, during power switch Q1 conducting, the primary winding current I of transformer T1
P1Current peak I
PKCan obtain by formula (1).
In formula (1), V
INBe input voltage; L
MInductance value for the elementary winding of transformer T1; T
ONON time for power switch Q1.
According to formula (1), the input power P of power supply device
ICan obtain by formula (2).
In formula (2), T
SSwitching cycle for power switch Q1.
Simultaneously, the power output P of power supply device
OCan obtain by formula (3).
P
O＝P
1×η＝V
O×I
O...(3)
In formula (3), η is a power conversion efficiency; V
OBe output voltage; I
OBe output current.With reference to formula (1), formula (2) and formula (3), can derive formula (4).
With reference to formula (4), make output current I
OBe a fixed constant (constant), so can obtain output voltage V
OWith primary winding current I
P1Current peak I
PKRelation formula (5).
In formula (5), K
1Be a constant, R is the resistance value of current detector R6.From formula (5), can obtain a conclusion, as long as that is accomplished exactly
Just can make output current I
OMaintain a fixed constant (constant).Simultaneously, primary winding current I
P1Current peak I
PKFlow through current detector R6, and go up the voltage peak V that produces current detection signal VCS in current detector R6
PK
In sum, the radical sign generator 12 of opening of the present invention is exactly to be used for to being proportional to output voltage V
OFeedback voltage signal VS open the radical sign computing, therefore, the Current limited Control signal VCL that holds radical sign generator 12 output can be proportional to the output voltage V of holding after the radical sign computing
O(that is,
).Then, according to the resulting conclusion of formula (5), on-off controller 14 of the present invention is used for comparison operation current detection signal VCS and Current limited Control signal VCL, and according to the switching of comparative result in order to power controlling switch Q1.So, the switch type power supplying device with output current restriction of first embodiment of the invention, its output current I
OReaching electric current restriction, and output voltage still can remain unchanged when descending.
Cooperate Fig. 3, with reference to figure 4.Fig. 4 is the switch type power supplying device with output current restriction of second embodiment of the invention.In second embodiment of the invention,, indicate with same-sign with the first embodiment components identical.The circuit operation principle of second embodiment and first embodiment is identical with the effect of reaching, its main difference be in: the pulse duration of second embodiment is adjusted controller U2 and is further comprised an error amplifier 16 and a voltage potential adjuster 18.Wherein, error amplifier 16 is coupled to feedback voltage processor 10 and voltage potential adjuster 18, and simultaneously, voltage potential adjuster 18 is coupled between error amplifier 16 and the on-off controller 14.Error amplifier 16 comparison operations, one reference voltage VREF1 and feedback voltage signal VS, and export an error amplification signal EA and give voltage potential adjuster 18.18 couples of error amplification signal EA of voltage potential adjuster carry out the voltage potential adjustment, give on-off controller 14 in order to export a voltage control signal VCTL.
At this moment; be coupled to power switch Q1, drive radical sign generator 12, the on-off controller 14 of voltage potential adjuster 18 and current detector R6; meeting comparison operation current detection signal VCS and Current limited Control signal VCL or comparison operation current detection signal VCS and voltage control signal VCTL when a normal condition when a guard mode; and; according to comparative result output drive signal DRV to power switch Q1; with the switching of power controlling switch Q1, and then reach the dual-use function of exporting voltage stabilizing and current limliting.
Cooperate Fig. 3, with reference to figure 5.Fig. 5 is the switch type power supplying device with output current restriction of third embodiment of the invention.In third embodiment of the invention,, indicate with same-sign with the first embodiment components identical.The circuit operation principle of the 3rd embodiment and first embodiment is identical with the effect of realization, its main difference be in: the feedback voltage processor 10 of third embodiment of the invention is coupled to the secondary winding P2 of transformer T1, to the secondary winding P2 of transformer T1 sampling feedback voltage V FB, and produce a feedback voltage signal VS by an optical coupling switch U2 based on this feedback voltage V FB.Open radical sign computing feedback voltage signal VS equally and drive radical sign generator 12, and export a Current limited Control signal VCL.And comparison operation current detection signal VCS and Current limited Control signal VCL when on-off controller 14 is used for a guard mode equally, and according to the switching of comparative result power controlling switch Q1.So, the switch type power supplying device with output current restriction of third embodiment of the invention, its output current I
OIn reaching electric current restriction, and output voltage still can remain unchanged when descending.
Cooperate Fig. 5, with reference to figure 6.Fig. 6 is the switch type power supplying device with output current restriction of fourth embodiment of the invention.The identical person with the 3rd embodiment of element in fourth embodiment of the invention indicates with same-sign.The circuit operation principle of the 4th embodiment and the 3rd embodiment is identical with the effect of realization, its main difference be in: the pulse duration of the 4th embodiment is adjusted controller U2 and is further comprised an error amplifier 16 and a voltage potential adjuster 18.Wherein, error amplifier 16 is coupled to feedback voltage processor 10 and voltage potential adjuster 18, and simultaneously, voltage potential adjuster 18 is coupled between error amplifier 16 and the on-off controller 14.Error amplifier 16 comparison operations, one reference voltage VREF1 and feedback voltage signal VS, and export an error amplification signal EA and give voltage potential adjuster 18.18 couples of error amplification signal EA of voltage potential adjuster carry out the voltage potential adjustment, give on-off controller 14 in order to export a voltage control signal VCTL.
At this moment; be coupled to power switch Q1, drive radical sign generator 12, the on-off controller 14 of voltage potential adjuster 18 and current detector R2; meeting comparison operation current detection signal VCS and Current limited Control signal VCL or comparison operation current detection signal VCS and voltage control signal VCTL when a normal condition when a guard mode; and; according to comparative result output drive signal DRV to power switch Q1; with the switching of power controlling switch Q1, and then reach the dual-use function of exporting voltage stabilizing and current limliting.
Cooperate Fig. 3 and Fig. 5, with reference to figure 7.Fig. 7 is the on-off controller circuit box schematic diagram that first embodiment of the invention and the 3rd embodiment use.In addition, cooperate Fig. 9, Fig. 9 is a control waveform schematic diagram of the present invention.On-off controller 14a includes a comparator 140, a noise eliminator 142, an overvoltage protection device 143, one or logical circuit 144, an oscillator 148, a trigger 146, a driver 149 and a phase shifts circuit 147.
Wherein, first reverse input end (-) of comparator 140 is coupled to out radical sign generator 12, in order to receive Current limited Control signal VCL.And the non-inverting input (+) of comparator 140 is coupled to current detector R6, R2, in order to received current detection signal VCS.And the output of comparator 140 (indicate) during greater than Current limited Control signal VCL, can be exported a pick-off signal S1 in this current detection signal VCS.
In addition, be coupled to the output of comparator 140 and the noise eliminator 142 of power switch Q1, according to pick-off signal S1 to export a noise-cancelling signal LEB to the control end of power switch Q1 (indicating), in order to eliminate the leading edge noise voltage VP of current detection signal VCS.Noise eliminator 142 and after noise-cancelling signal LEB output is transferred to pick-off signal S1 or the first input end (indicating) of logical circuit 144.Or second input of logical circuit 144 (indicate) then is couple to overvoltage protection device 143, to receive a guard signal OVP of overvoltage protection device 143 outputs.So, or logical circuit 144 is used for pick-off signal S1 and guard signal OVP are carried out or logical operation, gives trigger 146 to export a reset signal S2.Wherein, overvoltage protection device 143 is according to the comparative result of supply voltage VCC greater than a critical voltage VREF2, and output protection signal OVP.
The replacement end (R) of trigger 146 is coupled to or the output of logical circuit 144, in order to receive this reset signal S2.Simultaneously, the setting end (S) of trigger 146 is coupled to the output of oscillator 148, in order to receive a Continuity signal OSC from oscillator 148.And the output of trigger 146 is according to reset signal S2 and Continuity signal OSC, and from output (Q) output one control signal S3.
Wherein, when the Continuity signal OSC of oscillator 148 output high potentials gives the setting end (S) of trigger 146, the output of trigger 146 (Q) will produce the control signal S3 of high potential, export the drive signal DRV of high potentials to power switch Q1, so that power switch Q1 transfers conducting state to Control Driver 149.In addition, as current detection signal VCS during greater than Current limited Control signal VCL, the pick-off signal S1 of the high potential of comparator 140 outputs through noise eliminator 142 with or logical circuit 144, deliver to the replacement end (R) of trigger 146.The output of trigger 146 (Q) will produce the control signal S3 of electronegative potential, export the drive signal DRV of electronegative potentials to power switch Q1, so that power switch Q1 transfers not on-state to Control Driver 149.
So, on-off controller 14a of the present invention repeats the switching of power controlling switch Q1, to make the switch type power supplying device with output current restriction of the present invention, its output current I
OReaching electric current restriction, and output voltage still can remain unchanged when descending.
Cooperate Fig. 3 and Fig. 5, phase shifts circuit 147 among the on-off controller 14a is coupled to the output (Q) and feedback voltage processor 10 of trigger 146, the output blanking signal BLANK give feedback voltage processor 10, to allow the sampling sequential of feedback voltage processor 10 after blanking signal BLANK, in order to avoid voltage ring (RINGING) zone of feedback voltage processor 10 sampling at feedback voltage V FB, and then the corner voltage of the feedback voltage V FB that sampled accurately, to produce feedback voltage signal VS.
Cooperate Fig. 7, with reference to figure 8.Fig. 8 is the on-off controller circuit box schematic diagram that second embodiment of the invention and the 4th embodiment use.Its element of on-off controller 14b in Fig. 8 is identical with the on-off controller 14a in Fig. 7, indicates with same-sign.The circuit operation principle of on-off controller 14a among on-off controller 14b among Fig. 8 and Fig. 7 is identical with the effect of realization, its main difference be in: the employed comparator 140 of on-off controller 14b further includes one second reverse input end (-), and second reverse input end (-) is coupled to error amplifier 16, in order to receive voltage control signal VCTL.So, the output of comparator 140 can be at current detection signal VCS during greater than Current limited Control signal VCL, or current detection signal VCS is during greater than voltage control signal VCTL, and comparator 140 all can be exported pick-off signal S1.
With reference to figure 8, power switch Q1 transfers conducting state to according to the Continuity signal OSC of oscillator 148 output high potentials, and transfers not on-state to according to pick-off signal S1 again.So, on-off controller 14b of the present invention will repeat the switching of power controlling switch Q1, to make the switch type power supplying device with output current restriction of the present invention, reach the dual-use function of output voltage stabilizing and current limliting, and at output current I
OReaching electric current restriction, and output voltage still can remain unchanged when descending.
Cooperate Fig. 8, with reference to Figure 10, Figure 10 is the curve synoptic diagram of output current limiting of the present invention.In Figure 10, output current I
ODuring the restriction of no show still current value I L, at this moment, output voltage V
OAt 5V, and comparator 140 comparison operation current detection signal VCS and voltage control signal VCTL, with regulated output voltage V
OAt 5V.Simultaneously, as output current I
OWhen arriving restriction current value I L, output voltage V
OWith power output P
OCan begin to descend.Yet, this moment comparator 140 comparison operation current detection signal VCS and Current limited Control signal VCL, to stablize output current I
OAt restriction current value I L.In addition, work as output voltage V
OWhen continuing to drop to a set point VS, output current I
OGo back to zero.
Cooperate Fig. 3 to Fig. 6, please refer to Figure 11 A.Figure 11 A is the first embodiment schematic diagram of feedback voltage processor of the present invention.Wherein, feedback voltage processor 10 is that a voltage sampling and retentive control device 10a include a control circuit 102 and a sampling circuit 104.Control circuit 102 is coupled to auxiliary winding P3 or the secondary winding P2 of this transformer T1, obtains feedback voltage V FB from auxiliary winding P3 or secondary winding P2.Control circuit 102 comparison operation feedback voltage V FB and a reference voltage VREF3, and export a sampling control signal Samp.Sampling circuit 104 is coupled to control circuit 102, is controlled by sampling control signal Samp with the corner magnitude of voltage of sampling feedback voltage V FB and keep this corner magnitude of voltage, and exports this corner magnitude of voltage, to produce feedback voltage signal VS.
In control circuit 102, feedback voltage V FB and reference voltage VREF3 are to sample or to keep through comparator C OMP in order to judgement.When supposing that feedback voltage V FB is sample mode greater than reference voltage VREF3, after blanking signal BLANK finished, the comparative result of comparator C OMP can allow output (Q) generation one high-potential voltage of trigger FF1 come control switch Q3 conducting.The feedback voltage V FB variation of following feedback voltage V FB simultaneously through amplifier OP and charging or discharging current controller (Q2, Q4), and then capacitor C O charged.Because voltage sampling and retentive control device 10a are the throw characteristics of utilizing feedback voltage V FB waveform slope, grasp the corner voltage of feedback voltage V FB, so the charging current Ichg of design Q2 can be greater than the discharging current Idschg several times of Q4.
And when feedback voltage V FB is a hold mode during less than reference voltage VREF3, this moment, comparator C OMP can control trigger FF2 in order to replacement trigger FF1, transferred low-potential voltage with the output Q that makes trigger FF1 to by high-potential voltage, so that switch Q3 closes.So, the corner voltage of feedback voltage V FB just can be maintained among the capacitor C O.
In addition, in a cycle of oscillation, be subjected to the inductance value and the influence of load size of auxiliary winding P3, feedback voltage V FB the first time less than reference voltage VREF3 after, have the pulse that several are higher than reference voltage VREF3 again, this kind phenomenon can allow voltage sampling and retentive control device 10a produce misoperation.Therefore, the trigger FF2 among voltage sampling and the retentive control device 10a can be controlled by the drive signal DRV that on-off controller 14 is exported, and makes voltage sampling and retentive control device 10a only accept the corner voltage of primary feedback voltage V FB.
Cooperate Fig. 3 to Fig. 6, please refer to Figure 11 B.Figure 11 B is the second embodiment schematic diagram of feedback voltage processor of the present invention.Wherein, feedback voltage processor 10 is that a voltage sampling and retentive control device 10b include a plurality of sampling and keep single control circuit 106 and a sampling optimization circuits 108.Each sampling and keep single control circuit 106 all to be coupled to auxiliary winding P3 or the secondary winding P2 of transformer T1, and from auxiliary winding P3 or secondary winding P2 according to the slope of feedback voltage, the feedback voltage V FB of the different time of sampling respectively.And, each sampling and keep 106 couples of obtained feedback voltage V FB of single control circuit and a reference voltage VREF-1～VREF-n who sets separately to compare computing, and then produce different sampling voltage Vsamp-1～Vsamp-n.Then, sampling optimization circuits 108 is coupled to described sampling and keeps single control circuit 106, acceptance sampling voltage Vsamp-1～Vsamp-n, and, sampling optimization circuits 108 is according to described sampling voltage Vsamp-1～Vsamp-n, calculating the corner magnitude of voltage of feedback voltage V FB, and export this corner magnitude of voltage, to produce feedback voltage signal VS.
In addition, feedback voltage V FB is subjected to the inductance value of auxiliary winding P3 and the influence of load size, therefore, the obtaining of corner voltage of the auxiliary harmonic voltage of winding P3 when non-continuous mode is worked is difficult to get accurate value, so need do the optimization processing to sampling and the corner magnitude of voltage that keeps single control circuit 106 to be got, feed back the shortcoming of control switch formula power supply unit with the Voltage Feedback accuracy of improving primary side FEEDBACK CONTROL switch type power supplying device not as secondary side.
Cooperate Fig. 3 to Fig. 6, please refer to Figure 12, Figure 12 is the radical sign generator circuit schematic diagram of opening of the present invention.Wherein, open the characteristic that radical sign generator 12 utilizes MOS, with output voltage V
OBe input to two groups of living current generating circuits 122 with reference voltage VREF4, and then produce voltage VGS1 and voltage VGS2.Then, voltage VGS1 and voltage VGS2 are connected to the change-over circuit 124 of voltage transitions electric current, to produce output current accurately
Again output current Iout is multiplied by output resistance RO and obtains out the output voltage of radical sign
As mentioned above, the present invention obtains the accurate corner magnitude of voltage of auxiliary winding or the harmonic voltage of secondary winding when non-continuous mode is worked as FEEDBACK CONTROL by voltage sampling and retentive control device.Allow whole switch type power supplying device reach electric current when restriction by driving the radical sign generator again in output, output voltage descend but output current still may command remain unchanged, and reach the purpose of output overcurrent protection.
Certainly; the present invention also can have other various embodiments; under the situation that does not deviate from spirit of the present invention and essence thereof; those of ordinary skill in the art work as can make various corresponding changes and distortion according to the present invention, but these corresponding changes and distortion all should belong to the protection range of the appended claim of the present invention.
Claims (21)
1. the switch type power supplying device with output current restriction is characterized in that, comprising:
One transformer has an elementary winding, level winding and an auxiliary winding, and this transformer receives an input voltage from this elementary winding, and from this secondary winding induction output one output voltage, and from this auxiliary winding induction output one feedback voltage;
One power switch is coupled to the elementary winding of this transformer;
One current detector is coupled to this power switch, receives a primary winding current of this transformer by this power switch, and exports a current detection signal;
One feedback voltage processor, the auxiliary winding that is coupled to this transformer is to produce a feedback voltage signal based on this feedback voltage;
One drives the radical sign generator, is coupled to this feedback voltage processor, opens this feedback voltage signal of radical sign computing, and exports a Current limited Control signal; And
One on-off controller; couple this power switch, this drives radical sign generator and this current detector; this current detection signal of comparison operation and this Current limited Control signal when a guard mode, and export a drive signal to this power switch according to comparative result, to control the switching of this power switch.
2. the switch type power supplying device with output current restriction according to claim 1, it is characterized in that, further comprise an error amplifier, this error amplifier is coupled to this feedback voltage processor, comparison operation one reference voltage and this feedback voltage signal, and export an error amplification signal.
3. the switch type power supplying device with output current restriction according to claim 2, it is characterized in that, this feedback voltage processor is a voltage sampling and retentive control device, this voltage sampling and retentive control device are coupled to the auxiliary winding of this transformer, to sample this feedback voltage and keep this feedback voltage, in order to produce this feedback voltage signal.
4. the switch type power supplying device with output current restriction according to claim 2, it is characterized in that, further comprise a voltage potential adjuster, this voltage potential adjuster is coupled to this error amplifier and this on-off controller, receive this error amplification signal, and export a voltage control signal and give this on-off controller.
5. the switch type power supplying device with output current restriction according to claim 4 is characterized in that this on-off controller comprises:
One comparator, have one first reverse input end, one second reverse input end, a non-inverting input and an output, wherein this first reverse input end receives this Current limited Control signal, this second reverse input end receives this voltage control signal, this non-inverting input receives this current detection signal, and this output during greater than this voltage control signal, is exported a pick-off signal greater than this Current limited Control signal or this current detection signal in this current detection signal;
One noise eliminator, couple the output of this comparator and the control end of this power switch, this noise eliminator is according to this pick-off signal, export a noise-cancelling signal, wherein this noise-cancelling signal is delivered to the control end of this power switch, this noise eliminator is exported this pick-off signal after this noise-cancelling signal output;
One overvoltage protection device is exported a guard signal;
One oscillator is exported a Continuity signal;
One or logical circuit, be coupled to this noise eliminator and this overvoltage protection device, this pick-off signal and this guard signal are carried out or logical operation, to export a reset signal;
One trigger, have the end, of resetting and set an end and an output, wherein should replacements hold the output that is coupled to this or logical circuit, this setting is held and is coupled to this oscillator, this trigger receives this Continuity signal and this reset signal, and exports a control signal by this output; And
One driver is coupled to output and this power switch of this trigger, receives this control signal, and exports this drive signal to this power switch.
6. the switch type power supplying device with output current restriction according to claim 5, it is characterized in that, this on-off controller further comprises a phase shifts circuit, this phase shifts circuit is coupled to output and this voltage sampling and the retentive control device of this trigger, and exports a blanking signal to this voltage sampling and retentive control device.
7. the switch type power supplying device with output current restriction according to claim 3 is characterized in that this voltage sampling and retentive control device comprise:
A plurality of sampling circuits are coupled to the auxiliary winding of this transformer, described this feedback voltage of sampling circuit sequential sampling, and export a plurality of sampling voltages; And
One computing circuit is coupled to described sampling circuit, the described sampling voltage of this computing circuit computing, and a corner magnitude of voltage of exporting this feedback voltage.
8. the switch type power supplying device with output current restriction is characterized in that, comprising:
One transformer has an elementary winding and a level winding, and this transformer receives an input voltage from this elementary winding, and from this secondary winding induction output one output voltage and a feedback voltage;
One power switch is coupled to the elementary winding of this transformer;
One current detector is coupled to this power switch, receives a primary winding current of this transformer by this power switch, and exports a current detection signal;
One feedback voltage processor is coupled to this Secondary winding of transformer to produce a feedback voltage signal based on this feedback voltage;
One drives the radical sign generator, is coupled to this feedback voltage processor, opens this feedback signal of radical sign computing, and exports a Current limited Control signal; And
One on-off controller; be coupled to this power switch, this drives radical sign generator and this current detector; this current detection signal of comparison operation and this Current limited Control signal when a guard mode, and export a drive signal according to comparative result, to control the switching of this power switch.
9. the switch type power supplying device with output current restriction according to claim 8, it is characterized in that, further comprise an error amplifier, this error amplifier is coupled to this feedback voltage processing controller, comparison operation one reference voltage and this feedback voltage signal, and export an error amplification signal.
10. the switch type power supplying device with output current restriction according to claim 9, it is characterized in that, this feedback voltage processor is a voltage sampling and retentive control device, this voltage sampling and retentive control device are coupled to this Secondary winding of transformer, to sample this feedback voltage and keep this feedback voltage, in order to produce this feedback voltage signal.
11. the switch type power supplying device with output current restriction according to claim 9, it is characterized in that, further comprise a voltage potential adjuster, this voltage potential adjuster is coupled to this error amplifier and this on-off controller, receive this error amplification signal, and export a voltage control signal and give this on-off controller.
12. the switch type power supplying device with output current restriction according to claim 11 is characterized in that this on-off controller comprises:
One comparator, have one first reverse input end, one second reverse input end, a non-inverting input and an output, wherein this first reverse input end receives this Current limited Control signal, this second reverse input end receives this voltage control signal, this non-inverting input receives this current detection signal, and this output during greater than this voltage control signal, is exported a pick-off signal greater than this Current limited Control signal or this current detection signal in this current detection signal;
One noise eliminator, couple the output of this comparator and the control end of this power switch, this noise eliminator is according to this pick-off signal, export a noise-cancelling signal, wherein this noise-cancelling signal is delivered to the control end of this power switch, this noise eliminator is exported this pick-off signal after this noise-cancelling signal output;
One overvoltage protection device is exported a guard signal;
One oscillator is exported a Continuity signal;
One or logical circuit, be coupled to this noise eliminator and this overvoltage protection device, this pick-off signal and this guard signal are carried out or logical operation, to export a reset signal;
One trigger, have the end, of resetting and set an end and an output, wherein should replacements hold the output that is coupled to this or logical circuit, this setting is held and is coupled to this oscillator, this trigger receives this Continuity signal and this reset signal, and exports a control signal by this output; And
One driver is coupled to output and this power switch of this trigger, receives this control signal, and exports this drive signal to this power switch.
13. the switch type power supplying device with output current restriction according to claim 12, it is characterized in that, this on-off controller further comprises a phase shifts circuit, this phase shifts circuit is coupled to output and this voltage sampling and the retentive control device of this trigger, and exports a blanking signal to this voltage sampling and retentive control device.
14. the switch type power supplying device with output current restriction according to claim 10 is characterized in that this voltage sampling and retentive control device comprise:
A plurality of sampling circuits are coupled to the auxiliary winding of this transformer, described this feedback voltage of sampling circuit sequential sampling, and export a plurality of sampling voltages; And
One computing circuit is coupled to described sampling circuit, the described sampling voltage of this computing circuit computing, and a corner magnitude of voltage of exporting this feedback voltage.
15. a controller is coupled to a power supply circuit, it is characterized in that, comprising:
One feedback voltage processor is coupled to this power supply circuit, and this feedback voltage processor receives a feedback voltage from this power supply circuit, and produces a feedback voltage signal based on this feedback voltage;
One drives the radical sign generator, is coupled to this feedback voltage processor, opens this feedback voltage signal of radical sign computing, and exports a Current limited Control signal; And
One on-off controller; couple this and open radical sign generator and this power supply circuit; receive a current detection signal from this power supply circuit; this on-off controller is this current detection signal of comparison operation and this Current limited Control signal when a guard mode; and export a drive signal to this power supply circuit according to comparative result, to control this power supply circuit action.
16. controller according to claim 15 is characterized in that, further comprises an error amplifier, this error amplifier is coupled to this feedback voltage processor, comparison operation one reference voltage and this feedback voltage signal, and export an error amplification signal.
17. controller according to claim 16, it is characterized in that, this feedback voltage processor is a voltage sampling and retentive control device, this voltage sampling and retentive control device are coupled to this power supply circuit, to sample this feedback voltage and keep this feedback voltage, in order to produce this feedback voltage signal.
18. controller according to claim 16, it is characterized in that further comprise a voltage potential adjuster, this voltage potential adjuster is coupled to this error amplifier and this on-off controller, receive this error amplification signal, and export a voltage control signal and give this on-off controller.
19. controller according to claim 18 is characterized in that, this on-off controller comprises:
One comparator, have one first reverse input end, one second reverse input end, a non-inverting input and an output, wherein this first reverse input end receives this Current limited Control signal, this second reverse input end receives this voltage control signal, this non-inverting input receives this current detection signal, and this output during greater than this voltage control signal, is exported a pick-off signal greater than this Current limited Control signal or this current detection signal in this current detection signal;
One noise eliminator, couple the output of this comparator and the control end of this power switch, this noise eliminator is according to this pick-off signal, export a noise-cancelling signal, wherein this noise-cancelling signal is delivered to the control end of this power switch, this noise eliminator is exported this pick-off signal after this noise-cancelling signal output;
One overvoltage protection device is exported a guard signal;
One oscillator is exported a Continuity signal;
One or logical circuit, be coupled to this noise eliminator and this overvoltage protection device, this pick-off signal and this guard signal are carried out or logical operation, to export a reset signal; And
One trigger, have the end, of resetting and set an end and an output, wherein should replacements hold the output that is coupled to this or logical circuit, this setting is held and is coupled to this oscillator, this trigger receives this Continuity signal and this reset signal, and exports a control signal by this output; And
One driver is coupled to output and this power switch of this trigger, receives this control signal, and exports a drive signal to this power switch.
20. controller according to claim 17, it is characterized in that, this on-off controller further comprises a phase shifts circuit, this phase shifts circuit is coupled to output and this voltage sampling and the retentive control device of this trigger, and exports a blanking signal to this voltage sampling and retentive control device.
21. controller according to claim 17 is characterized in that, this voltage sampling and retentive control device comprise:
A plurality of sampling circuits are coupled to the auxiliary winding of this transformer, described this feedback voltage of sampling circuit sequential sampling, and export a plurality of sampling voltages; And
One computing circuit is coupled to described sampling circuit, the described sampling voltage of this computing circuit computing, and a corner magnitude of voltage of exporting this feedback voltage.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNA2008101112795A CN101604915A (en) | 2008-06-13 | 2008-06-13 | Switch type power supplying device and controller with output current restriction |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNA2008101112795A CN101604915A (en) | 2008-06-13 | 2008-06-13 | Switch type power supplying device and controller with output current restriction |
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| Publication Number | Publication Date |
|---|---|
| CN101604915A true CN101604915A (en) | 2009-12-16 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNA2008101112795A Pending CN101604915A (en) | 2008-06-13 | 2008-06-13 | Switch type power supplying device and controller with output current restriction |
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| Country | Link |
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| CN (1) | CN101604915A (en) |
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| CN101814848A (en) * | 2010-04-16 | 2010-08-25 | 上海宣研电子科技有限公司 | Constant output current control circuit and control method for fly-back switch power supply |
| CN103715910A (en) * | 2012-10-05 | 2014-04-09 | Nxp股份有限公司 | Switched-mode power supply |
| CN104242661A (en) * | 2013-06-19 | 2014-12-24 | 戴乐格半导体公司 | Precise output power detection |
| CN104620499A (en) * | 2012-07-10 | 2015-05-13 | 努吉拉有限公司 | Interference suppression for switched mode power supply with error correction |
| CN105099194A (en) * | 2014-05-07 | 2015-11-25 | 环旭电子股份有限公司 | Flyback-type converter with function of improving overcurrent protection, and control circuit therefor |
| CN105591556A (en) * | 2014-11-07 | 2016-05-18 | 电力集成公司 | Input Overvoltage Protection Using Current Limit |
| CN107508457A (en) * | 2017-09-08 | 2017-12-22 | 中国船舶重工集团公司第七0四研究所 | Direct-current dual power starts and switching current-limiting circuit |
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| CN101814848A (en) * | 2010-04-16 | 2010-08-25 | 上海宣研电子科技有限公司 | Constant output current control circuit and control method for fly-back switch power supply |
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| CN104242661A (en) * | 2013-06-19 | 2014-12-24 | 戴乐格半导体公司 | Precise output power detection |
| CN104242661B (en) * | 2013-06-19 | 2017-10-31 | 戴乐格半导体公司 | Accurate power output detection |
| CN105099194B (en) * | 2014-05-07 | 2017-10-24 | 环旭电子股份有限公司 | Tool improves the direction flyback converter and its control circuit of overcurrent protection |
| CN105099194A (en) * | 2014-05-07 | 2015-11-25 | 环旭电子股份有限公司 | Flyback-type converter with function of improving overcurrent protection, and control circuit therefor |
| CN105591556A (en) * | 2014-11-07 | 2016-05-18 | 电力集成公司 | Input Overvoltage Protection Using Current Limit |
| CN105591556B (en) * | 2014-11-07 | 2019-07-12 | 电力集成公司 | Use the input overvoltage protection of current limit |
| CN107508457A (en) * | 2017-09-08 | 2017-12-22 | 中国船舶重工集团公司第七0四研究所 | Direct-current dual power starts and switching current-limiting circuit |
| CN108512442A (en) * | 2017-11-27 | 2018-09-07 | 昂宝电子（上海）有限公司 | Switching power control system |
| CN108512442B (en) * | 2017-11-27 | 2020-11-13 | 昂宝电子（上海）有限公司 | Switching power supply control system |
| CN110768537A (en) * | 2019-11-20 | 2020-02-07 | 深圳原能电器有限公司 | Bilateral feedback and control DSR framework |
| CN110768537B (en) * | 2019-11-20 | 2021-07-16 | 深圳原能电器有限公司 | Bilateral feedback and control DSR framework |
| CN112363396A (en) * | 2020-11-24 | 2021-02-12 | 成都芯源系统有限公司 | Intelligent switch system |
| CN112363396B (en) * | 2020-11-24 | 2023-02-10 | 成都芯源系统有限公司 | Intelligent switch system |
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