CN101330256B - Method and apparatus for regulating a diode conduction duty cycle - Google Patents
Method and apparatus for regulating a diode conduction duty cycle Download PDFInfo
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- CN101330256B CN101330256B CN200810100382.XA CN200810100382A CN101330256B CN 101330256 B CN101330256 B CN 101330256B CN 200810100382 A CN200810100382 A CN 200810100382A CN 101330256 B CN101330256 B CN 101330256B
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M3/00—Conversion of dc power input into dc power output
- H02M3/22—Conversion of dc power input into dc power output with intermediate conversion into ac
- H02M3/24—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters
- H02M3/28—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac
- H02M3/325—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal
- H02M3/335—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only
- H02M3/33507—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of the output voltage or current, e.g. flyback converters
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M1/00—Details of apparatus for conversion
- H02M1/08—Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M1/00—Details of apparatus for conversion
- H02M1/0003—Details of control, feedback or regulation circuits
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- Power Engineering (AREA)
- Dc-Dc Converters (AREA)
Abstract
The invention relates to a method and a device used for adjusting diode conduction duty rati. A power converter control method and apparatus is disclosed. A control circuit for use in a power converter according to aspects of the present invention includes a clock signal generator coupled to generate a clock signal to control switching of a power switch to be coupled to the control circuit. Feedback circuitry is coupled to receive a feedback signal, which is representative of an output of a power converter during a feedback portion of an off time of the power switch. The feedback circuitry is coupled to respond to the feedback signal to control the clock signal generator to regulate a duty cycle of the feedback portion of the off time of the power switch as a proportion of a total power switch switching cycle period.
Description
the reference of earlier application
It is No.60/919 that the present invention has required the application number of submitting on March 23rd, 2007,690, and name is called the rights and interests of the U.S. Provisional Application of " method and apparatus that regulates diode conduction duty cycle ".
Technical field
The present invention relates generally to the control circuit of the output parameter of by-pass cock mode power converter, especially relate to a kind of control circuit, it regulates the duty ratio as the ratio of diode current flow time and switch periods.
Background technology
Power converter control circuit can be used to multiple object and application.Here require the function of control circuit can reduce control circuit peripheral components quantity.The minimizing energy minimization power converter of peripheral components quantity, to improve its portability, reduces the final needed design cycle number of power converter designs of determining, has improved the reliability of end product simultaneously.In addition, the number of components of minimizing can provide the energy efficiency in the operation of power converter to improve, and can reduce the cost of power converter.Potentiality that the minimizing of this power converter part count provides are on the one hand to simplify or remove and previously in power converter, realize output current and regulate needed peripheral circuit.
At the isolation flyback converter for AC/DC power transfer, output current is typically measured by connecting a sensing element, and this sensing element typically is resistor, and this sensing element is connected the electric current flowing through in power output terminal with sensing.This sensing induced current is used to produce feedback signal, and this feedback signal is connected to the control circuit in the primary side of power supply, and it typically adopts photoelectrical coupler, isolated with the output of power supply.
As bust-boost converter, boost converter, in the non-insulating power supply of SEPIC transducer or Cuk transducer, typically adopt the signal that produces representative mobile output current in power output terminal as the sensing element of sense resistor, produce the feedback signal that represents power converter output current.
In isolation and non-isolating converter configuration, power switch is coupled to power supply input and energy transmission, as power switch during in conducting state electric current from power supply inlet flow overpower switch and energy transmission.Control circuit is the switching with power ratio control switch in response to feedback signal, to regulate the power delivery that is input to output from power converter.
Summary of the invention
According to an aspect of the present invention, provide a kind of control circuit for power converter, described control circuit comprises: clock-signal generator, and it is coupled into the clock signal that produces the switch of controlling the power switch that is coupled to this control circuit; And feedback circuit, it is coupled into receiving feedback signals, the output of described feedback signal representative power converter during the power switch feedback fraction of opening time, described feedback circuit is coupled into the described feedback signal of response and controls described clock-signal generator, thereby in the time that the duty ratio of the ratio of the feedback fraction as power switch opening time and whole power switch switch periods reaches threshold value, regulate described duty ratio, thereby regulate the output of described power converter.
According to another aspect of the present invention, provide a kind of control circuit for power converter, having comprised: clock-signal generator, it is coupled into the clock signal that produces the switch of controlling the power switch that is coupled to control circuit, feedback circuit, it is coupled into receiving feedback signals, the output of described feedback signal representative power converter during the power switch feedback fraction of opening time, described feedback circuit is coupled into the described feedback signal of response and controls described clock-signal generator, thereby in the time that the duty ratio of the ratio of the feedback fraction as power switch opening time and whole power switch switch periods reaches threshold value, regulate described duty ratio, thereby regulate the output of described power converter, wherein said feedback circuit further comprises feedback condenser, described feedback condenser is coupled into during the power switch feedback fraction of opening time and charges, and, described feedback condenser is coupled into the remainder electric discharge in whole power switch switch periods, this feedback circuit also comprises the first current source and the second current source, described the first current source and the second current source are coupled into described feedback condenser charging and discharging, and voltage stabilizing circuit, this voltage stabilizing circuit is coupled to feedback circuit, to stablize respectively the first voltage and the second voltage at the first current source and the second current source two ends.
According to a further aspect of the present invention, provide a kind of control circuit for power converter, having comprised: clock-signal generator, it is coupled into the clock signal that produces the switch of controlling the power switch that is coupled to control circuit, feedback circuit, it is coupled into receiving feedback signals, the output of described feedback signal representative power converter during the power switch feedback fraction of opening time, described feedback circuit is coupled into the described feedback signal of response and controls described clock-signal generator, thereby in the time that the duty ratio of the ratio of the feedback fraction as power switch opening time and whole power switch switch periods reaches threshold value, regulate described duty ratio, thereby regulate the output of described power converter, wherein said clock-signal generator further comprises and is coupled into response described feedback circuit and keep the non-oscillating comparator of oscillator, wherein said feedback circuit comprises feedback condenser, described feedback condenser is coupled into during the power switch feedback fraction of opening time and charges, and, described feedback condenser is coupled into the remainder electric discharge in whole power switch switch periods.
According to another aspect of the present invention, a kind of power converter is provided, comprise: energy transmission, described energy transmission is coupling between power converter input and power converter output, and this power converter input comprises first input end and the second input terminal; Be coupled to the power switch of energy transmission, mobile between first input end and the second input terminal by described energy transmission and described power switch to make at described power switch conduction period electric current; And be coupled to the control circuit of described power switch, described control circuit is coupled into receiving feedback signals, the output of described feedback signal representative power converter during the described power switch feedback fraction of opening time, wherein said control circuit is coupled in the time that the duty ratio of the ratio of the feedback fraction as described power switch opening time and whole power switch switch periods reaches threshold value, regulate described duty ratio, thereby regulate the output of described power converter.
According to another aspect of the present invention, provide a kind of method for power ratio control transducer, having comprised: power switch is switched to conducting and disconnection; Produce feedback signal, the power converter of described feedback signal representative in during the described power switch feedback fraction of opening time exported; And the switching of controlling described power switch is using in the time that the duty ratio of the ratio of the feedback fraction as described power switch opening time and whole power switch switch periods reaches threshold value, regulates described duty ratio, thereby regulates the output of described power converter.
Accompanying drawing explanation
Embodiment and the following accompanying drawing of exemplary reference non-limiting and non exhaustive property of the present invention are described, and unless otherwise indicated, in different views, identical Reference numeral has represented identical parts.
Fig. 1 generality shows according to the exemplary retrace power converter of the control circuit of the employing responsive feedback signal of teaching of the present invention, the duty ratio of the adjustable ratio as diode current flow time and switch periods of this feedback signal.
Fig. 2 generality shows according to the oscillogram of the power converter of the exemplary control circuit of employing of teaching of the present invention, and this power converter responsive feedback signal is to regulate as the duty ratio of the ratio of diode current flow time and switch periods.
Fig. 3 A shows a part for the exemplary control circuit of teaching according to the present invention in more detail.
Fig. 3 B shows a part for the oscillating circuit of teaching according to the present invention.
Fig. 4 generality shows according to teaching of the present invention, the oscillogram of the exemplary control circuit of the duty ratio of the ratio of responsive feedback signal using adjusting as diode current flow time and switch periods.
Fig. 5 is that the output voltage of exemplary power transducer of the exemplary control circuit of employing of the teaching according to the present invention is with respect to the characteristic figure of output current.
Fig. 6 shows the exemplary non-isolated power converter of the exemplary control circuit of employing of the teaching according to the present invention.
Fig. 7 show according to the present invention teaching for regulating the flow chart that is transferred to the illustrative methods of the power of power converter output from power converter input.
Embodiment
At this, the method and apparatus of the control circuit for implementing regulating power transducer output parameter is disclosed.In the following description, multiple specific detail is provided to for helping thorough understanding of the present invention.But clearly, those of ordinary skills do not need to adopt this specific detail to realize the present invention.In other samples, known material or method are not described in detail to avoid making the present invention indefinite.
" embodiment " who mentions in whole explanation, " embodiment ", " example " or " example " mean that special characteristic, structure or the characteristic of the description being associated with this embodiment or example are included at least one embodiment of the present invention.Therefore, in " in one embodiment " that do not exist together and occur of whole explanation, " in one embodiment ", the phrase of " example " or " example ", same embodiment or the example that must not refer to.And, this special characteristic, structure or characteristic can combine with any suitable combination and/or sub-portfolio in one or more embodiment or example.In addition, should be appreciated that, the accompanying drawing providing at this is for the task of explanation to those of ordinary skills, and accompanying drawing unnecessaryly describe in proportion.
To the control circuit for regulating power transducer output parameter of the teaching according to the present invention be described below.Example of the present invention comprises the method and apparatus of one or more output parameters of regulating power transducer.
Fig. 1 generality shows the power converter 100 of the control circuit of the employing regulating power transducer output parameter of the teaching according to the present invention, sometimes also referred to as power supply.In one example, power converter 100 is isolation flyback converters, and wherein primary side ground end 107 and primary side return terminal 126 are electrically isolated from one.Should be noted that in other example, according to teaching of the present invention, power converter 100 can have more than one output.
As shown, control circuit 115 is coupled to power switch 105, and in one example, this power switch 105 is mos field effect transistor (MOSFET) or bipolar transistor etc.Power switch 105 is connected to the input winding 103 of energy transmission 109, and it is coupled to DC input voltage 101 and power output diode 117.In one example, DC input voltage 101 is the output that is coupled to the rectification circuit of unshowned alternating-current voltage source.Electric capacity 106 is coupled to power converter input 190 and 191, with at power switch 105 during in conducting state, for first and second inputs 190 and 191 of flowing through, the switching current (switching current) of energy transmission 109 windings 103 and power switch 105 provides low impedance source.In one example, control circuit 115 and switch 105 can form the part as the integrated circuit of mixing or monolithic integrated circuit manufacture.Control circuit 115 is coupled into receiving feedback signals 114, and still benefits from teaching of the present invention, and in one example, this feedback signal 114 is voltage signals, but in other example, also can be current signal or other and represent the signal of power converter output.
In the example depicted in fig. 1, control circuit 115 is coupled into and regulates the power that is sent to the power converter output 192 and 193 that is connected to load 121 from the first and second inputs 190 and 191 of power converter 100.In one example, the certain power transducer output parameter being conditioned is DC output current I
o120.Energy transmission 109 comprises input winding 103 and output winding 110 and auxiliary winding 108.Feedback signal 114 is coupled to control circuit 115 from auxiliary winding 108 by the resitstance voltage divider being made up of resistor 111 and 112.
In operation, control circuit 115 regulates the output of power supply 100 with switch power switch 105 by responsive feedback signal 114.When switch 105 conductings, energy transfers to the input winding 103 of energy transmission 109 from capacitor 106.When this switch disconnects, the energy being stored in input winding 103 is transferred to output winding 110.Be transferred to the output of power supply 100 from the energy of output winding 110, electric current is flowed through a forward bias power output diode 117 to capacitor 118 and the load 121 that is coupled to output 192 and 193.When in the time that switch 105 off period electric currents are flowed through power output diode 117, the output voltage V at load 121 two ends
o119 add that the forward drop of power output diode 117 equates with the voltage at output winding 110 two ends substantially.
As will be described, the voltage of exporting winding 110 two ends in the time that electric current is flowed through output diode represents output voltage V
o119 o'clock, this part of the opening time of power switch was called the feedback fraction T of the opening time of power switch 105
fB.In some situation, at the off period of power switch 105, electric current may stop flowing through power output diode 117 from output winding 110 substantially.In this case, the voltage drop that power output diode 117 was reverse biased and exported winding 110 two ends no longer represents output voltage V
o119.In the time there is no that electric current is flowed through power output diode 117, this part of the opening time of this power switch 105 is called the non-feedback fraction of the opening time of power switch 105.
The voltage at output winding 110 two ends is reflected into the auxiliary winding 108 of energy transmission based on turn ratio.The voltage at auxiliary winding 108 two ends is therefore at the power switch feedback fraction T of 105 opening times
fBmay be utilized during this time, to obtain the feedback signal 114 about the output of power supply 100, this feedback signal 114 is coupled into by control circuit 115 and receives, and regulates the output of power supply 100 with the switch of power ratio control switch 105.
In one example, circuit blocks 194 comprises the diode 113 that is coupled to auxiliary winding 108 as shown in Figure 1.During the ON time of power switch 105, auxiliary winding diode 113 is reverse biased and therefore stops the electric current resistor 111 and 112 of flowing through.Benefit from equally teaching of the present invention, in other example, the basic short circuit shown in circuit blocks 194 comprises connects 195.
Comprise that in circuit blocks 194 in an embodiment of this basic short circuit connection 195,, during power switch 105 ON time, a signal is applied to the terminal 123 of control circuit 115.But this signal is feed-forward signal, it does not represent the output of power converter but representative comes across the power input voltage at capacitor 106 two ends.In one example, control circuit 115 is coupled into during the ON time of power switch 105 in response to feed-forward signal 114.In another example, control circuit 115 is coupled into the feed-forward signal 188 that response directly obtains by being coupled to capacitor 106.Therefore, comprise in this example of basic short circuit connection 195 in circuit blocks 194, therefore signal 114 is only still that representative is at the power switch feedback fraction T of 105 opening times
fBthe feedback signal of the output voltage 119 of power converter 100 during this time.In one example, the feedback fraction T of 105 opening times of this power switch
fBbe that electric current 198 is flowed through time period of power output diode 117, it will be described with reference to the example shown in figure 2.
Fig. 2 shows the exemplary waveforms of the exemplary electrical dataway operation that contributes to general key diagram 1.For example, waveform 200 is V in Fig. 1
fB116 voltage oscillogram.Waveform 214 is the current waveforms of drain current 104 of power switch 105 of flowing through in Fig. 1.Waveform 230 is the current waveforms of diode current 198 of power diode 117 of flowing through in Fig. 1.Waveform 240 is to have represented whether the flow through feedback control signal waveform of power output diode 117 in Fig. 1 of electric current.In other words, in described example, waveform 240 has represented in the time that power switch 105 disconnects whether conduction current of power output diode 117.In illustrated example, because power output diode current 232 was substantially zero before times 250 conducting at power switch 105, waveform 214 and 230 shows interrupted current waveform.Therefore in the time of power switch 105 conducting, drain current waveform 209 is from the electric current 215 being substantially zero.
In each switch periods, power switch, in ON time Ton 204 conductings, disconnects at turn-off time Toff206.At the feedback fraction T of power switch Toff206 opening time
fBduring 205, the flow through power output diode 117 of power converter 100 of electric current 232, and the voltage occurring at output winding 110 two ends is substantially equal to output voltage 119 and adds the forward drop of power diode 117.Feedback fraction T
fB205 are commonly referred to (reflected) voltage period of reflection.
In the example shown, the flow through electric current 198 of power output diode 117 be substantially equal to the flow through electric current of output capacitor 118 and the output current I of the load 121 of flowing through
o120 summation.Because the forward voltage of diode 117 substantially can be by the data acquisition of manufacturer, the voltage that therefore winding 110 two ends occur has represented output voltage 119.And the voltage that winding 108 two ends occur is relevant to the voltage at 108 turn ratio and winding 110 two ends by winding 110.For example,, if winding 110 and 108 has the identical number of turn, at the switch feedback fraction T of opening time
fBduring 205, the voltage that winding 110 occurs with winding 108 two ends is by single order is identical substantially.For fear of obscuring teaching of the present invention, as the second order impact of leakage inductance and interwinding capacity is not described in detail at this.
At the switch feedback fraction T of opening time
fBduring 205, therefore the voltage that winding 108 two ends occur also represented output voltage 119.In one example, by feedback voltage signal 208 and threshold voltage levels 236 are compared, to produce the logic-high value of signal 242 in the time that feedback voltage signal 208 is larger than threshold voltage levels 236, produce waveform 240 to generate feedback control signal Dcond 241.Therefore,, in the time that electric current is flowed through power stage diode 117 in Fig. 1, logical signal 242 is high duration and time period T
fB205 equate substantially.
In another example, the threshold voltage levels 280 lower than the value of threshold level 236 may be utilized, to produce Dcond feedback control signal 241.This lower threshold voltage levels is to electric power output voltage amplitude therefore more insensitive to the amplitude of feedback voltage signal 208.For example, in the power converter of Fig. 1, in the time that output voltage 119 reduces in High Output Current situation, the amplitude of the feedback voltage signal 208 relevant to earth potential 202 also declines.Be used to produce in the example of Dcond feedback control signal 241 at threshold voltage levels 236, the amplitude of feedback voltage signal 208 is reduced to the always degree (this will cause Dcond feedback control signal 241 All Time in keep logic low) higher than feedback voltage signal 208 of threshold voltage levels 236, and it will no longer represent that electric current flows through time period of output diode 117.Lower threshold level 280 has been got rid of this situation.
Should be noted that in one example, lower threshold voltage levels 280 is introduced two other consideration.In one example, first consideration is that Dcond signal time slot has increased time period Terr 282.This Terr 282 introduces error in Dcond241 waveform, and this is because it no longer accurately represents that electric current flows through time period of output diode 117.Therefore, in one example, the circuit of control circuit 115 inside need to compensate this error.
In one example, the parasitic relaxation ringing waveform (parasitic relaxation ringing waveform) that second consideration is feedback voltage signal 208 has exceeded compared with low-threshold power voltage level 280 at time period Trg 281, it is high by 283 that this can produce wrong logic in Dcond feedback control signal 241, unless control circuit 115 comprises the circuit of eliminating the second logic high 283.Such circuit can comprise latch in one example, and it is arranged to from time period T
fB205 end point is until start next power switch switch periods at time point 284, and it is low keeping Dcond241 signal.
In another example, one or two of above-mentioned consideration can be avoided as follows: design control circuit 115, uses the variable threshold voltage level of comparing with feedback voltage signal 208 to produce Dcond feedback control signal 241.In one example, this variable threshold voltage level can change according to the amplitude of feedback voltage signal 208 between threshold voltage level 236 and 280.In one example, obtain as follows this variable voltage threshold level: the T after power switch turn-offed in the time 275
fBthe amplitude of some the set time sampled feedback signals 208 during 205, and sampled amplitude is deducted to fixed value.In one example, this fixed value is to be substantially equal to the voltage of 0.5 volt.
Because feedback signal 114 (is V in this example
fB116) relevant to the voltage that winding 108 two ends occur with the resitstance voltage divider being made up of with 112 resistor 111 by known circuit blocks 194, therefore feedback signal 114 has represented the feedback fraction T at power switch Toff206 opening time
fBthe output voltage of power supply during 205.
Should note, Ton204 during power switch 105 ON time, if if circuit blocks 194 comprises diode 113 or have inner clamp circuit (clamp) (not shown) to be coupled to terminal 123, the voltage that appears at the feedback terminal 123 of Fig. 1 is substantially zero volt with respect to ground terminal 124.In Fig. 2, this kind of situation illustrate by voltage level 213, and it is substantially equal to ground voltage 202.
Be appreciated that the horizontal I of average output current of the lead-out terminal 192 and 193 of flowing through Fig. 1 from the waveform of Fig. 2
oUTAVE235, for example, can be according to following relation from I
dIODE233 waveshape obtains:
Wherein, T
fB/ T has represented the feedback fraction T of power switch opening time
fBduty ratio with the ratio of whole power switch switch periods T.Due to I
oDIDEpkby the input winding and output umber of turn ratio Np/Ns and I of the Np 170 in known energy transmission 109 and Ns171
dpkrelevant, so I
oUTAVEcan be from I
d210 and I
dpk201 peak value calculates:
Due to ratio, Np/Ns fixes, can find out if in equation (2) I
dpksubstantially fixing, power supply average output current I
oUTAVE235 can be by regulating as T
fB205 with the duty cycle adjustment of the ratio of power switch switch periods T212.In other words, I
oUTAVE235 can be by regulating the duty cycle adjustment as the ratio of power output diode current flow time and power switch switch periods 212.
T
fBtime period 205 is by following equation control
Wherein in one example, L is the inductance of energy transmission output winding 110 in Fig. 1, and it measures in all other windings of energy transmission and external circuit uncoupling, V
othe output voltage 119 of Fig. 1, V
dIODEto work as electric current I
dIODEthe forward drop of output diode 117 in 198 Fig. 1 while flowing.Due to the V in equation (3)
dIODEsubstantially fix in given power converter with L, therefore, for fixed value I
dpk, should be noted that if output voltage V
oreduce T
fBto increase.This situation relates to the electric current adjustment operation region of the power converter reducing along with load 121 impedance decline output voltages 119.This operating area discusses in detail in the back with reference to Fig. 5.
Fig. 3 A shows an example arrangement according to the circuit 300 of teaching of the present invention, and this circuit 300 can form a part for the internal circuit of control circuit 315 in one example, and control circuit 315 can be the control circuit 115 in Fig. 1 in one example.According to teaching of the present invention, the circuit shown in Fig. 3 A is an example of circuit, represents the power switch feedback fraction T of opening time when being coupled into receive
fBwhen the feedback signal of power converter output voltage, described circuit can be by regulating as the power switch feedback fraction T of opening time during this time
fBwith the duty ratio of the ratio of whole power switch switch periods, thereby regulate from the power delivery of the output that is input to power converter of power converter, described feedback fraction T
fBbeing substantially equal in one example electric current flows through time period of power output diode 117.
Shown in example, control circuit 315 is coupled at feedback terminal 323 receiving feedback signals V as described
fB316.In one example, control circuit 315 comprises feedback circuit, and it at least comprises Dcond signal generator module 399, switch 313,314, feedback condenser 360 and current source 307 and 308.Feedback signal V
fB316 are applied to Dcond signal generator circuit module 399.In other examples, Dcond signal generator module 399 can be configured to receive feedback current signal, can eliminate the demand to external resistor 312, and feedback signal can comprise the electric current of resistor 311 to feedback terminal 323 of flowing through.In one example, Dcond feedback control signal 302 outputs of circuit module 399 are identical with the Dcond feedback control signal 241 in Fig. 2.In order to produce Dcond feedback control signal 302, Dcond generator circuit module 399 can adopt one or more technology of discussing above with reference to Fig. 2.
In one example, Dcond feedback control signal 302 is anti-phase by inverter 303, is then coupled to the grid of switch 313 and an input with door 305.Be coupled to the grid of switch 314 with the output of door 305.To further describe with reference to figure 4 rear with the object of door 305, but, for the object of current explanation, signal 328 is assumed that height, therefore the signal 331 of the vertical grid of using switch 314 equates with the signal 327 of the grid that is applied to switch 313, this is due to the explanation for current, and signal 328 is assumed that height.When signal 327 is for low switch 313 during thus in conducting state, feedback condenser 360 charges with the speed being determined by current source 308.When signal 327 is for height switch 314 during thus in conducting state, feedback condenser 360 discharges with the speed being determined by current source 307.
Therefore, the mean value of the voltage Va360 at feedback condenser 360 two ends is determined by the duty ratio of Dcond feedback control signal 302.In the time that voltage Va360 reaches threshold value Vref1317, the output signal 324 of comparator 325 becomes height.In one example, when output signal 324 is high, oscillating circuit 333 is coupled into the high impulse delay comparator output signal of next clock signal 334 is kept to high that time.In one example, the beginning of oscillating clock signal 334 high impulse starting power switch 105 switch periods ON time sections.As will be discussed, in one example, according to teaching of the present invention, comparator 325 and oscillator 333 are included as a part for the clock generating circuit of control circuit 315, with the switch of power ratio control switch, thus the output of regulating power transducer.
The detailed operation of the circuit in Fig. 3 A is described below with reference to the waveform of Fig. 4 and the exemplary power output voltage of Fig. 5 and the characteristic curve of output current.Fig. 4 shows the three groups of waveforms 400,430 and 460 that represent three output loading situations of power converter, and this power converter can be the power converter 100 in Fig. 1 in one example.Sets of waveforms 400 is for low loading condition, for example POL 512 in Fig. 5.Sets of waveforms 430 is for example, output loading situation near the transition point (POL 513 Fig. 5) from voltage-regulation region 503 to electric current control band 507 for power supply.Sets of waveforms 460 is for example, output loading situation at electric current control band (POL 514 in Fig. 5) for power work.The curve that should note Fig. 5 is Utopian, and, although operating area 503 and 507 is regions that voltage and current is conditioned, and not meaning that they are constant, they also can change according to output voltage and current conditions.Every group of waveform 400,430,460 comprises 3 waveforms, show identical with signal 334 in Fig. 3 A in one example clock signal waveform 401, the Dcond feedback control signal waveform 402 identical with signal 302 in Fig. 3 A in one example, and the Va waveform 403 identical with Va320 in Fig. 3 A in one example.
Light load condition shown in waveform 400 comprises the oscillating clock signal waveform 407 with switch periods T1412.In one example, clock signal 407 produces by oscillator and is used to as in the control circuit of the control circuit 115 in Fig. 1, with initial as the conducting period of the power switch of the power switch 105 in Fig. 1.Waveform 400 also shows starting point and the Dcond waveform 408 that power switch ON time Ton1405 is clock signal 407 pulses and is converted to the time period between logic height from logic low.In this example, Dcond signal 408 is in duration T
fB1the 406th, logic high.At time period T
fB1during this time, the feedback condenser 360 in Fig. 3 A is with fixed rate charging, and Va403 is at T
fB1when finishing, is increased to time period maximum.When Dcond feedback control signal 408 becomes lowly, feedback condenser 360 is discharged to a lower voltage level 411.With reference to figure 3A, this lower voltage level is reference voltage Vref 2304.In the time that voltage Va320 is reduced to lower than reference voltage level Vref2304, signal 328 becomes low, and therefore setting is low with a door output signal 331, prevents that feedback condenser 360 from further discharging.In one example, this clamper lower limit (lower clamp limit) in Va voltage is arranged on 1.25V, change with the maximum that is set to high required Va320 by the output of restriction comparator 325, improve the transient response of control circuit 315, this will be described below.
In example waveform 430, in the time that Ton2432 is larger than Ton1405, clock signal 431 switch periods T2434 are substantially identical with T1412.Because the switch periods temporal power switch conduction time for substantially the same is longer, the increase compared with waveform 400 of power switch duty ratio, therefore waveform 430 shows the output current loading condition of increase compared with waveform 400.Should be noted that and be used to this control circuit increasing along with load increase of regulating power duty cycle of switching, can adopt the common power supply control technology as voltage mode or Controlled in Current Mode and Based.In other example, variable frequency control strategy can increase power switch duty ratio in order to the load along with increasing, although in these situations, power switch switch periods time T 2 may be different from the cycle of waveform 400 412.No matter the control strategy adopting how, the ratio of power switch ON time and switch periods, is commonly called power switch duty ratio, higher in waveform 430 than waveform 400.
Dcond feedback control signal 402 duty ratio T in the certain loads situation shown in waveform 430
fB2/ T2 is than 50% slightly high situation.In current source 308 in Fig. 3 A example substantially the same with 307, because each switch periods feedback condenser 360 charge ratios are long discharge time, therefore the loading condition of waveform 430 has caused average voltage Va403 to increase.At time point 438, voltage Va403 reaches upper limit threshold voltage level 436, its in one example with Fig. 3 A in Vref1317 equivalence.At point 438, signal 324 will become height and initial oscillator conservation condition continues for some time, larger than threshold voltage 436 this section of time Va signal waveform 435.
At the T shown in waveform 460
fBincrease caused the longer time of feedback condenser in Fig. 3 A charging, make voltage Va320 exceed threshold voltage levels 466, threshold voltage levels 466 is substantially equal to 1.75 volts in one example.At the time point 469 of waveform 460, Dcond feedback control signal 402 becomes low and feedback condenser 360 and starts electric discharge.At time point 470, voltage Va465 is reduced to lower than threshold voltage levels 466.Va signal 465 higher than time period of threshold voltage levels 466 as T
hold468 illustrate.In one example, for T
hold468 time periods, the comparator 325 in Fig. 3 A is output as height, and control circuit oscillator 333 is kept, and this has postponed next clock signal 334 high impulses, has therefore postponed the beginning of next power switch 105 switch periods.Therefore signal 334 is used to the switch of power ratio control switch.
Therefore in the example of Fig. 4, work as T
fB2433 are reached for 50% the threshold value of switch periods T2434, and as shown in waveform 430, the average voltage on the feedback condenser 360 in Fig. 3 A increases.When the maximum of Va403 reaches threshold voltage levels 466, oscillator clock signal 431 is delayed.Work as T
fBreach value T
fB3, oscillator clock signal 461 postpones an amount T
hold468.Due at time period T
hold468, Dcond feedback control signal 402 is high within time of 50% substantially, is low, so as T within time of 50% substantially
fB3463 keep constant substantially with the duty ratio of the ratio of whole switch periods T3464.In other examples, in Fig. 3 A, the current value of current source 307 and 308 can be not identical, T thus
fBit is not 50% value that time period 205 and the ratio of switch periods 206 can be adjusted to one.Therefore do not consider the relative value of current source 307 and 308, in the time that duty ratio reaches a threshold value, control circuit 315 is coupled into and regulates this duty ratio, and this duty ratio is the power switch feedback fraction T of opening time
fBratio with whole power switch switch periods.Should note in above-mentioned description, oscillator 333 periodic responses are in the voltage at capacitor 360 two ends.
Due to T
fB3463 have represented that electric current flows through time period of the power diode 117 in Fig. 1, therefore the waveform of Fig. 4 shows the switch of control circuit 315 power ratio control switches, to regulate as the flow through duty ratio of the time period of power output diode and the ratio of whole switch periods of electric current.Reference equation (2), can find out, if I
dpksubstantially fixing, the average output current of power supply can be by regulating as the electric current duty ratio of the time period of power diode and the ratio of whole switch periods of flowing through, and regulated.
In one example, control circuit 315 further comprises voltage stabilizing circuit 309, and it is coupled into and makes the first voltage V1393 at the first current source 307 two ends during the opening time of the first switch 314 keep the voltage substantially occurring with feedback condenser 360 two ends to equate.
In this example, voltage stabilizing circuit module 309 is used to help to improve the precision of circuit 315.There is no voltage stabilizing circuit 309, the voltage at current source 307 and 308 two ends can produce great changes in the time of switch 313 and 314 turn-on and turn-off.During next power switch switch periods, when switch 313 and 314 is again when conducting, this will introduce initial error in the charging and discharging electric current of actual current source circuit.These initial current errors have reduced the precision of the charging and discharging electric current that flows to feedback condenser 360, have reduced the precision of regulating power converter output current.
Still turn-off for switch 313 and 314 conductings the substantial constant that all keeps voltage drop, in the time that switch 313 turn-offs, voltage stabilizing circuit 309 has been established a voltage at node 319, and it equates with the voltage at node 319 places when switch 313 conducting substantially.Equally, in the time that switch 314 turn-offs, circuit 309 has been established a voltage at node 326, and it equates with the voltage at node 326 places when switch 314 conducting substantially.This function provides by unity gain amplifier 306, and its output is by connecting 321 voltages that remain on feedback condenser 360 two ends.The output of unity gain amplifier 306, is coupled to node 326 when low at signal 327, be coupled to node 319 at signal 327 when high.In this way, in the time that switch 313 and 314 provides current path for flowing into the electric current of capacitor 360, current source 313 and 314 has been established the current value that they that flow into capacitor 360 are conditioned substantially immediately.
Fig. 3 B shows as a part for an example of the pierce circuit of oscillator 333 in Fig. 3 A.Oscillator 333 in Fig. 3 B is coupled with reception oscillator inhibit signal 362, and it can be the signal 324 in Fig. 3 A in one example.In following description, mentioned voltage is all with reference to the earth potential 341 of Fig. 3 B.The basic operation of pierce circuit 333 sees below.When comparator 355 output signals 348 are high, switch 357 closures, Vlow356 voltage is applied to the non-oppisite phase end of comparator 355.Putative signal 362 is the low moment, allows oscillator operation, and inverter 342 is output as height, with the output of door 359 be also height, therefore conducting of transistor switch 350.Therefore capacitor 352 discharges with the definite speed of the value by current source 345.Because signal 348 is high, or door 344 is output as height, and therefore transistor switch 349 turn-offs.In the time that the voltage Vosc351 at capacitor 352 two ends is discharged to threshold value Vlow356, the output of comparator 355 becomes low, and switch 357 turn-offs, because inverter 363 outputs become height, switch 354 conductings, and Vhi voltage 353 is applied to the non-oppisite phase end of comparator 355.Because comparator output 348 is low, be therefore output as lowly with door 359, transistor switch 350 turn-offs.If oscillator inhibit signal 362 is still low, so or door 344 output become low, turn-on transistor switch 349.Capacitor 352 is with the determined speed charging of current source 346.In one example, current source 346 has the current value lower than current source 345.In the time that voltage Vosc351 reaches Vhi threshold value 353, the output of comparator 355 becomes height again, repeats the above-mentioned cycle.But door 342,359 and 344 is coupled to become capacitor 352 voltage Vosc351 when high when oscillator inhibit signal 362 and keeps substantial constant at signal 362 during the high time period.No matter capacitor 352 is charging or electric discharge in this time, the above-mentioned fact that is all.An example of this function illustrates by waveform 364, and waveform 364 shows Vosc voltage 351 during Osc inhibit signal 362 is for the high time period and keeps constant.
In one example, oscillator clock signal 334 can, by adopting the output signal 343 of inverter 347 inverse gates 344 input that it is applied to single-shot trigger circuit 358 to produce, obtain clock signal 334 thus.Should be appreciated that and have the multiple mode that realizes above-mentioned oscillator function, only use the example shown in Fig. 3 B in the mode of example.
Fig. 5 also shows electric power output voltage 501 and output current 502 and how to depart from ideal current regulating characteristics at output voltage 501 when low.In one example, the operation under output-voltage levels 509 is considered to the failure condition of being indicated by region 508.Be used in the example in battery charger application at power converter, the operation under the output voltage lower than 509 has represented battery being finished etc.In an example, need to follow by foldback (foldback) characteristic shown in characteristic 504.In another example, need linear characteristic 505, in other example, can accept the characteristic 506 that output current 502 increases at the voltage lower than voltage 509.
Fig. 6 shows the schematic diagram 600 according to the exemplary non-isolated power converter of teaching of the present invention.In the example shown, exemplary non-isolated power converter is illustrated as bust-boost converter.The non-insulating power supply that should be appreciated that other form also can benefit from teaching of the present invention, and described non-insulating power supply can comprise such as, but not limited to, boost converter, SEPIC transducer, Cuk transducer etc.In the example shown, control circuit 615 is shared its operation in many aspects with above-mentioned control circuit 115 and 315.In one example, energy transmission does not need auxiliary winding, replacement, there is magnitude of voltage V
fB616 feedback signal is coupled to control circuit 615 from main energy transmission 609 windings 694.
In operation, when power switch 605 is in conducting state, electric current 604 flows between the one 691 and the 2 692 input of power supply 600 by energy transmission 609 and power switch 605.In the time that power switch 605 disconnects, at the power switch feedback fraction T of opening time
fBduring this time, the lower voltage of node 693 is to the value that is substantially equal to output ground rail voltage 607 and deducts the forward drop at power output diode 630 two ends, wherein power diode 630 is coupled to energy transmission 609, to maintain electric current flowing in energy transmission 609.At the power switch feedback fraction T of 605 opening times
fBduring this time, in the time of power output diode 630 conduction current, the voltage at energy transmission 609 two ends equals output voltage 619 and adds the forward diode voltage drop at diode 630 two ends, has therefore represented at the power switch feedback fraction T of 605 opening times
fBoutput voltage 619 during this time.Mobile electric current in power output diode 630, is substantially equal to flow into the electric current of output capacitor 618 and mobile output current 620 sums in load 621.As shown in example, the resitstance voltage divider that the voltage at energy transmission winding 694 two ends forms by circuit module 613 with by resistor 611 and 612 is coupled to the feedback end 623 of control circuit 615, as having magnitude of voltage V
fB616 feedback signal.
In the example shown, feedback signal voltage value V
fB616 are only coupled to control circuit 615 from energy transmission 609 windings 694 during the opening time of power switch 605.In one example, circuit module 613 comprises the diode 695 that is coupled to main energy transmission winding 694.During the ON time of power switch 605, diode 695 reverse bias, have therefore stoped electric current flowing in resistor 611 and 612.
Benefit from according to teaching of the present invention, in another example, circuit module 695 comprises that basic short circuit connects 696.Comprise that at described circuit module 695 in the example of basic short circuit connection 696, signal is applied to the terminal 623 of control circuit 615 during power switch 605 ON time.But during power switch 605 ON time, this signal does not represent the output voltage of power converter.According to teaching of the present invention, comprise in the example of basic short circuit connection 696 thering is magnitude of voltage V at circuit module 613
fBtherefore 616 feedback signal is only still also at the power switch feedback fraction T of 605 opening times
fBrepresent during this time the feedback signal of the output voltage 619 of power converter 600, feedback fraction T
fBduring having electric current to flow into diode 630.In an example of non-isolation boosting-step-down controller circuit of Fig. 6, because the forward drop at diode 695 two ends tends to offset the forward drop at diode 630 two ends, therefore circuit module 613 tends to comprise diode 695, to be conducive to guaranteeing that feedback signal 614 accurately represents output voltage 619.
Therefore, in one example, the operating principle of control circuit 615 and above-mentioned control circuit 115 and 315 similar.In the time that the electric current of inflow diode 630 is reduced to null value substantially, the feedback fraction T that power switch 605 disconnects
fBfinish.Control circuit 615 is coupled into and regulates as the power switch feedback fraction T of opening time
fBduty ratio with the ratio of whole power switch switch periods.In one example, the circuit of discussing with reference to figure 3A can be used to provide this operation.
Fig. 7 generality shows according to flow chart 700 of the present invention, and it is described and regulates an illustrative methods that is sent to the power of the output of power converter from the input of power converter.As the example shows, receiving feedback signals in piece 701.In piece 703, determine whether at the power switch feedback fraction T of 105 opening times
fBin.If so,, in piece 705, feedback condenser 360 is charged by the current source 308 of fixing.In piece 730, determine whether the voltage Va at feedback condenser 360 two ends exceedes threshold value Vref1.If so, in piece 711,333, oscillator is kept nonoscillatory, and in piece 701 receiving feedback signals again.If the voltage Va at feedback condenser 360 two ends is lower than threshold value Vref1, oscillator 333 is allowed to work on and receiving feedback signals again in piece 701.In piece 703, if the time of determining is not at the power switch feedback fraction T of 105 opening times
fBin,, in piece 707, feedback condenser 360 is discharged by fixed current source 307.In piece 709, determine whether the voltage Va at feedback condenser 360 two ends exceedes threshold value Vref1.If so, in piece 711,333, oscillator is kept nonoscillatory, and in piece 701 receiving feedback signals again.If the voltage Va at feedback condenser 360 two ends is lower than threshold value Vref1, in piece 715, oscillator 333 is allowed to work on, and capacitor 360 continues to be discharged by fixed current source 307.Should be appreciated that, consistent with the operation of the circuit in Fig. 3 A, capacitor 360 only will be discharged during higher than lower threshold level Vref2304 at the voltage at capacitor 360 two ends.In piece 717, determine whether be the moment that produces the high signal pulse of next oscillator clock now, in the time arriving this moment, in piece 720, piece 720 allows the high signal conduction power switch of next clock pulse.In piece 721, determine whether power switch ON time section completes, and in piece 722, power switch is turned off and stops capacitor 360 to discharge, but should notice that the electric discharge of capacitor 360 stops if capacitor 360 voltages 320 have reached Vref2304 threshold voltage.
Therefore, according to teaching of the present invention, adopt the exemplary flow method of Fig. 7, can be by the switch in response to duty cycling power switch, to regulate the power that is sent to output from the input of power converter, described duty ratio is the power switch feedback fraction T of opening time
fBratio with whole power switch switch periods.
Above-mentioned to the description of control circuit 315 in, the cycle of oscillator 333 is in response to the voltage at capacitor 360 two ends in Fig. 3 A.Should be noted that and benefit from equally teaching of the present invention, in another example, cycle oscillator can be in response to the value of digit counter circuit.In one example, for the power switch feedback fraction of opening time, digit counter circuit can, with the frequency increments higher than power switch switching frequency, in other parts of power switch switch periods, successively decrease with the higher frequency of specific power switch switching frequency.The value of digit counter counting then can with threshold value comparison, and allow oscillator work during lower than threshold value when rolling counters forward, when rolling counters forward during higher than threshold value oscillator be stopped.Should be noted that and benefit from equally the present invention's teaching widely, other technology also can be used for substituting above-mentioned explanation to control cycle oscillator, thus the feedback fraction that regulating power switch disconnects and the ratio of power switch switch periods.
The above-mentioned explanation of examples shown of the present invention, is included in and describes in summary, is not that attempt is carried out exhaustive or it is limited to its disclosed concrete form.Here be in order to illustrate to specific embodiment described in the invention and example object, the various equivalence change that does not depart from the wider spirit and scope of the present invention is possible.In fact, should be appreciated that the specific voltage providing, electric current, frequency, power range values, the time etc., object is for explanation, according to teaching of the present invention, also can adopt other value in other embodiment and example.
Under the enlightenment of above-mentioned detailed description, example of the present invention can be made these modifications.The term using in following claim is not for the present invention being limited to explanation and the disclosed specific example of claim.But the establishment statement restriction of explaining according to claim is by the whole definite scope of following claim.Therefore specific explanation and accompanying drawing should be considered to be to describe only and not limitation accordingly.
Claims (13)
1. for a control circuit for power converter, described control circuit comprises:
Clock-signal generator, it is coupled into the clock signal that produces the switch of controlling the power switch that is coupled to this control circuit; And
Feedback circuit, it is coupled into receiving feedback signals, the output of described feedback signal representative power converter during the power switch feedback fraction of opening time, described feedback circuit is coupled into the described feedback signal of response and controls described clock-signal generator, thereby described control circuit regulates the duty ratio as the feedback fraction of power switch opening time and the ratio of whole power switch switch periods
Wherein, described feedback circuit comprises:
Feedback condenser, described feedback condenser is coupled into during the power switch feedback fraction of opening time and charges, and wherein said feedback condenser is coupled into the remainder electric discharge in whole power switch switch periods;
The first current source and the second current source, described the first current source and described the second current source are coupled in response to described feedback signal described feedback condenser charging and discharging;
Voltage stabilizing circuit, described voltage stabilizing circuit is coupled to described the first current source and described the second current source, to stablize respectively the first voltage and the second voltage at described the first current source and described the second current source two ends,
Wherein, described voltage stabilizing circuit comprises the amplifier with the input that is coupled to described feedback condenser, the output of wherein said amplifier is coupled into by charging or electric discharge in response to described feedback condenser, and is coupled respectively to described the first current source or described the second current source.
2. control circuit claimed in claim 1, wherein feedback signal is feedback voltage.
3. control circuit claimed in claim 1, wherein feedback signal is feedback current.
4. control circuit claimed in claim 1, wherein clock-signal generator comprises and is coupled into the oscillator vibrating in response to feedback circuit.
5. control circuit claimed in claim 1, wherein said clock-signal generator comprises comparator and oscillator, wherein said comparator is coupled into the described feedback circuit of response and keeps oscillator nonoscillatory.
6. control circuit claimed in claim 1, wherein said feedback circuit comprises the testing circuit of the feedback fraction of determining power switch opening time.
7. control circuit claimed in claim 6, when conduction current of the output of wherein said testing circuit by detection power transducer, determines the power switch feedback fraction of opening time.
8. control circuit claimed in claim 6, wherein testing circuit comprises diode current flow testing circuit, for detection of when conduction current of the power output diode of power converter, thereby determines the feedback fraction of the opening time of power switch.
9. for a control circuit for power converter, comprising:
Clock-signal generator, it is coupled into the clock signal that produces the switch of controlling the power switch that is coupled to control circuit;
Feedback circuit, it is coupled into receiving feedback signals, the output of described feedback signal representative power converter during the power switch feedback fraction of opening time, described feedback circuit is coupled into the described feedback signal of response and controls described clock-signal generator, thereby described control circuit regulates the duty ratio as the feedback fraction of power switch opening time and the ratio of whole power switch switch periods
Wherein said feedback circuit further comprises feedback condenser, described feedback condenser is coupled into during the power switch feedback fraction of opening time and charges, and, described feedback condenser is coupled into the remainder electric discharge in whole power switch switch periods, this feedback circuit also comprises the first current source and the second current source, and described the first current source and the second current source are coupled into described feedback condenser charging and discharging; And
Voltage stabilizing circuit, this voltage stabilizing circuit is coupled to feedback circuit, to stablize respectively the first voltage and the second voltage at the first current source and the second current source two ends, and
Wherein, described voltage stabilizing circuit comprises the amplifier with the input that is coupled to described feedback condenser, the output of wherein said amplifier is coupled into by charging or electric discharge in response to described feedback condenser, and is coupled respectively to described the first current source or described the second current source.
10. control circuit claimed in claim 9, wherein, described clock-signal generator comprises comparator and oscillator, wherein said comparator is coupled into the described feedback circuit of response and keeps oscillator nonoscillatory.
11. control circuits claimed in claim 9, wherein feedback signal is feedback voltage.
12. control circuits claimed in claim 9, wherein feedback signal is feedback current.
13. 1 kinds of power converters, comprising:
Energy transmission, described energy transmission is coupling between power converter input and power converter output, and this power converter input comprises first input end and the second input terminal;
Be coupled to the power switch of energy transmission, mobile between first input end and the second input terminal by described energy transmission and described power switch to make at described power switch conduction period electric current; And
According to the control circuit described in any one in claim 1 to 12.
Applications Claiming Priority (6)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US91969007P | 2007-03-23 | 2007-03-23 | |
| US60/919,690 | 2007-03-23 | ||
| US60/919690 | 2007-03-23 | ||
| US12/047,124 | 2008-03-12 | ||
| US12/047124 | 2008-03-12 | ||
| US12/047,124 US8008903B2 (en) | 2007-03-23 | 2008-03-12 | Method and apparatus for regulating a diode conduction duty cycle |
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| CN101330256A CN101330256A (en) | 2008-12-24 |
| CN101330256B true CN101330256B (en) | 2014-05-28 |
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| CN200810100382.XA Expired - Fee Related CN101330256B (en) | 2007-03-23 | 2008-03-21 | Method and apparatus for regulating a diode conduction duty cycle |
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5694305A (en) * | 1996-08-30 | 1997-12-02 | Astrodyne Corporation | Method and apparatus for protection of electronic circuitry |
| CN1547319A (en) * | 2003-12-03 | 2004-11-17 | 伊博电源（杭州）有限公司 | Forward circuit combining active clamping and accessory power supply circuit |
| CN1783682A (en) * | 2004-11-29 | 2006-06-07 | 崇贸科技股份有限公司 | Switching type controller and method for produuing suitching signal |
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| CN100466438C (en) * | 2004-05-24 | 2009-03-04 | 松下电器产业株式会社 | Switching power supply |
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2007
- 2007-04-23 KR KR1020070039386A patent/KR20080086799A/en not_active Application Discontinuation
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Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5694305A (en) * | 1996-08-30 | 1997-12-02 | Astrodyne Corporation | Method and apparatus for protection of electronic circuitry |
| CN1547319A (en) * | 2003-12-03 | 2004-11-17 | 伊博电源（杭州）有限公司 | Forward circuit combining active clamping and accessory power supply circuit |
| CN1783682A (en) * | 2004-11-29 | 2006-06-07 | 崇贸科技股份有限公司 | Switching type controller and method for produuing suitching signal |
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