CN103138556B - Pfc circuit, load driving circuits and signal control method - Google Patents
Pfc circuit, load driving circuits and signal control method Download PDFInfo
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- CN103138556B CN103138556B CN201110376593.8A CN201110376593A CN103138556B CN 103138556 B CN103138556 B CN 103138556B CN 201110376593 A CN201110376593 A CN 201110376593A CN 103138556 B CN103138556 B CN 103138556B
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
- H05B45/30—Driver circuits
- H05B45/37—Converter circuits
- H05B45/3725—Switched mode power supply [SMPS]
- H05B45/385—Switched mode power supply [SMPS] using flyback topology
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B20/00—Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps
- Y02B20/30—Semiconductor lamps, e.g. solid state lamps [SSL] light emitting diodes [LED] or organic LED [OLED]
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Abstract
The invention discloses a kind of pfc circuit, load driving circuits and signal control method, the input of described pfc circuit receives chopping voltage, and described pfc circuit comprises: main switch and Ton control unit; The control signal of described Ton control unit, being less than or equal in maximum range, with the copped wave angle positive correlation of described chopping voltage; Described pfc circuit also comprises: detect compensating unit, for detecting the copped wave angle of chopping voltage, generates amplitude and the positively related compensating signal in copped wave angle; Control according to the comparison signal of described compensating signal to Ton control unit, make to be less than or equal in maximum range in described control signal, the control signal rising that equal copped wave angle is corresponding.The present invention can shorten the invalid adjustment process in dimming process.
Description
Technical field
The present invention relates to circuit field, particularly relate to a kind of pfc circuit, load driving circuits and signal control method.
Background technology
At lighting field, a lot of occasion needs the brightness or the color that regulate light source, and this just requires that illuminator has regulatory function.Comparatively conventional is copped wave light regulating technology at present, as shown in Figure 1, dotted portion is a kind of implementation structure of existing copped wave dimmer, line voltage Vac is after the effect of copped wave dimmer, voltage on light source load RL is chopping voltage as shown in Figure 2, and the phase angle [alpha] that in copped wave dimmer, the transistor TRIAC triggering and conducting time is corresponding is the copped wave angle of chopping voltage.In copped wave dimmer, resistance R11 is a variable resistor, and the resistance of adjustment variable resistor R11 can change the size of copped wave angle α, and concrete: variable resistor R11 resistance is less, the triggering and conducting time of transistor TRIAC is shorter, and α is less at copped wave angle; Variable resistor R11 resistance is larger, and the triggering and conducting time of transistor TRIAC is longer, and α is larger at copped wave angle.When variable resistor R11 is adjusted to maximum value, corresponding copped wave angle α is called maximum copped wave angle, and when variable resistor R11 is adjusted to minimum resistance, corresponding copped wave angle α is called minimum copped wave angle.
But when light source load is non-resistance light source, when needing drive circuit to drive, its light modulation principle is different from above-mentioned principle.Be illustrated in figure 3 tunable optical drive circuit when light source load is LED, load driving circuits comprises: the first rectifier and pfc circuit, line voltage Vac is after copped wave dimmer, the first rectifier, obtain the input voltage vin of chopping voltage as pfc circuit, the input current of pfc circuit is Iin, and the output current Io of pfc circuit is for driving load.Pfc circuit also comprises: current control unit, ton control unit and driving control unit; Wherein,
The output current Io of current control unit to pfc circuit samples, and sampled signal is compared with reference signal, control signal Vr is exported after closed-loop adjustment, the change of this control signal Vr and the change inverse correlation of output current Io, namely, when output current Io reduces, this control signal Vr increases, otherwise, when output current Io increases, this control signal Vr reduces.And this control signal Vr has maximum Vrmax, namely when Vr equals Vrmax, when output current Io continues to reduce, Vr no longer increases.
Control signal Vr compares with a comparison signal Vp by ton control unit, determines the ON time ton of main switch S1, driving control unit according to this ON time output drive signal Vd to control main switch S1.Concrete, as shown in Figure 4, comparison signal Vp is triangular wave or sawtooth waveforms, the initial time that the moment starting to increase with comparison signal Vp is main switch S1 ON time Ton, the cut-off time of moment for main switch S1 ON time Ton of the amplitude of control signal Vr is equaled with the peak value of comparison signal Vp, namely, when Vr equals Vrmax, the ON time Ton of main switch S1 is maximum of T on-max.
When the copped wave angle α of the chopping voltage that copped wave dimmer exports is zero, current control unit is operated in closed loop states, the output current Io substantially constant of pfc circuit, when copped wave angle α increases from zero, chopping voltage mean value reduces, the output current Io of pfc circuit is reduced, the sampled signal of the output current Io that current control unit receives reduces, its control signal Vr exported increases, make the ON time Ton of main switch S1 elongated by Ton control unit, maintain the output current Io substantially constant of pfc circuit, when copped wave angle, α increases to α x, when the control signal Vr that current control unit is exported is increased to Vrmax, current control unit is in the critical condition of closed loop open loop, that is: when copped wave angle α continues to increase from currency α x, chopping voltage mean value continues to reduce, the output current Io of pfc circuit reduces, because Vr equals Vrmax, Vr no longer increases, the ON time Ton of main switch S1 equals maximum of T on-max, also no longer increase, current control unit is in open loop situations, the i.e. reduction of the output current Io of pfc circuit, the control signal Vr change that current control unit can not be made to export, therefore, the output current Io of pfc circuit can not be regulated by the ON time changing main switch S1.Can find out, because the state of current control unit corresponding to Vrmax is closed loop open loop critical condition, so Vr is more large more close to critical condition.
When current control unit is in open loop situations, the ON time Ton of main switch S1 is constant and equal maximum of T on-max, namely when copped wave angle α continues to increase from critical value α x, the mean value of the input voltage vin of pfc circuit reduces thereupon, therefore, the output current Io of pfc circuit reduces thereupon, thus realize: in the scope being greater than critical value α x, when copped wave angle α increases, the output current Io of pfc circuit reduces, when copped wave angle α reduces, the output current Io of pfc circuit increases, thus realizes light modulation.
Therefore, in the α change procedure of copped wave angle, only when current control unit is in open loop situations, copped wave dimmer could realize dimming function.And the copped wave angle α of chopping voltage is adjusted to the process of critical value α x by copped wave dimmer from zero, pfc circuit output current Io remains unchanged, and is skimble-skamble for light modulation, and for user, the adjustment process in this stage is invalid adjustment process.
Therefore, the invalid adjustment process how shortened in dimming process is the problem needing to solve.
Summary of the invention
In view of this, the technical problem to be solved in the present invention is, provides a kind of pfc circuit, load driving circuits and signal control method, can shorten the invalid adjustment process in dimming process.
For this reason, the embodiment of the present invention adopts following technical scheme:
The embodiment of the present invention provides a kind of pfc circuit, and the input of described pfc circuit receives chopping voltage, and described pfc circuit comprises: main switch and Ton control unit; The control signal of described Ton control unit, being less than or equal in maximum range, with the copped wave angle positive correlation of described chopping voltage;
Described pfc circuit also comprises:
Detecting compensating unit, for detecting the copped wave angle of chopping voltage, generating amplitude and the positively related compensating signal in copped wave angle; Control according to the comparison signal of described compensating signal to Ton control unit, make to be less than or equal in maximum range in described control signal, the control signal rising that equal copped wave angle is corresponding.
Wherein, detect compensating unit to comprise:
Detection sub-unit, for detecting the copped wave angle of chopping voltage;
Generate subelement, for generating the positively related compensating signal of amplitude and copped wave angle;
Control subelement, for controlling according to the comparison signal of described compensating signal to Ton control unit.
Control subelement specifically for: described compensating signal is added on the comparison signal of Ton control unit.
Described compensating signal is current signal; Described comparison signal is sawtooth signal;
Ton control unit comprises: constant-current source is respectively by the first electric capacity and second switch pipe ground connection, and the unearthed first end of the first electric capacity connects the inverting input of the first operational amplifier; The normal phase input end of the first operational amplifier is used for reception control signal;
Control subelement comprises: two outputs generating subelement connect the two ends of the first electric capacity respectively.
Described compensating signal is voltage signal; Described comparison signal is sawtooth signal, and compensating signal is level signal;
Ton control unit comprises: the normal phase input end of the first operational amplifier is used for reception control signal;
Control subelement comprises:
First input end is for receiving comparison signal, and first input end also connects the inverting input of the first operational amplifier by the first resistance; The compensating signal output generating subelement connects the inverting input of the first operational amplifier by the second resistance.
Described detection sub-unit comprises:
First input end passes through the 3rd resistance and the 4th grounding through resistance successively, the second input end grounding; 3rd resistance is connected the base stage of the first triode with the tie point of the 4th resistance, the emitter grounding of the first triode, and collector electrode connects the first output of detection sub-unit, the second output head grounding of detection sub-unit;
Generation subelement comprises:
The first input end generating subelement connects the first output of detection sub-unit, and the second input generating subelement connects the second output of detection sub-unit;
The first input end generating subelement connects supply voltage by the 5th resistance, also by the second capacity earth; Generate the first input end of subelement successively by the first diode and the 3rd capacity earth; The negative electrode of the first diode connects the base stage of the second triode, and the emitter-base bandgap grading of the second triode is by the 6th grounding through resistance, and the collector electrode of the second triode connects supply voltage; The emitter-base bandgap grading of the second triode is connected the compensating signal output generating subelement successively with the 7th resistance by the second diode.
Described detection sub-unit comprises: first input end passes through the 3rd resistance and the 4th grounding through resistance successively, the second input end grounding; 3rd resistance is connected the base stage of the first triode with the tie point of the 4th resistance, the emitter grounding of the first triode, and collector electrode connects the first output of detection sub-unit, the second output head grounding of detection sub-unit;
Generation subelement comprises:
The first input end generating subelement connects the first output of detection sub-unit, and the second input generating subelement connects the second output of detection sub-unit;
The first input end generating subelement connects supply voltage by the 5th resistance, also by the second capacity earth; Generate the first input end of subelement successively by the first diode and the 3rd capacity earth; The negative electrode of the first diode connects the base stage of the second triode, and the emitter-base bandgap grading of the second triode is by the 6th grounding through resistance, and the collector electrode of the second triode connects supply voltage; The emitter-base bandgap grading of the second triode is as the compensating signal output generating subelement.
The embodiment of the present invention also provides a kind of signal control method, and the method is applied to pfc circuit, and the input of described pfc circuit receives chopping voltage; Described pfc circuit comprises: main switch and Ton control unit; The control signal of described Ton control unit, being less than or equal in maximum range, with the copped wave angle positive correlation of described chopping voltage;
The method comprises:
Detect the copped wave angle of chopping voltage;
Generate amplitude and the positively related compensating signal in copped wave angle;
Control according to the comparison signal of described compensating signal to Ton control unit, make to be less than or equal in maximum range in described control signal, the control signal rising that equal copped wave angle is corresponding.
Carry out control according to described compensating signal to the comparison signal of Ton control unit to comprise:
Described compensating signal is added on the comparison signal of Ton control unit.
The embodiment of the present invention also provides a kind of load driving circuits, comprises above-mentioned pfc circuit.
Technique effect for technique scheme is analyzed as follows:
Increase in pfc circuit and detect compensating unit, this detection compensating unit detects the copped wave angle of chopping voltage, generates amplitude and the positively related compensating signal in copped wave angle; Control according to the comparison signal of described compensating signal to Ton control unit; Thus the comparison signal in Ton control unit is become new comparison signal, the ON time Ton of main switch is temporarily diminished, and then the output current that current control unit maintains ON time Ton and pfc circuit by closed-loop adjustment is constant, the control signal making identical copped wave angle corresponding raises, achieve the value raising control signal under the closed loop states of current control unit, also namely shorten the invalid adjustment process in dimming process.
Accompanying drawing explanation
Fig. 1 is a kind of implementation structure schematic diagram of prior art copped wave dimmer;
Fig. 2 is a kind of chopping voltage schematic diagram of prior art;
Fig. 3 is prior art light source load driving circuit structure schematic diagram;
Fig. 4 is prior art signal relation schematic diagram;
Fig. 5 is the electrical block diagram of embodiment of the present invention pfc circuit;
Fig. 6 is the implementation structure schematic diagram that the embodiment of the present invention detects compensating unit;
Fig. 7 is the specific embodiment schematic diagram of the first pfc circuit of the present invention;
Fig. 8 is embodiment of the present invention signal relation schematic diagram;
Fig. 9 is the specific embodiment schematic diagram of the second pfc circuit of the present invention;
Figure 10 is embodiment of the present invention signal relation schematic diagram;
Figure 11 is embodiment of the present invention detection sub-unit and the circuit realiration structural representation generating subelement;
Figure 12 is embodiment of the present invention signal control method schematic flow sheet.
Embodiment
In the α change procedure of copped wave angle, only when current control unit is in open loop situations, copped wave dimmer could realize dimming function.And the copped wave angle α of chopping voltage is adjusted to the process of critical value α x by copped wave dimmer from zero, pfc circuit output current Io remains unchanged, and is skimble-skamble for light modulation, and for user, the adjustment process in this stage is invalid adjustment process.
Inventor finds through large quantity research, and reduce critical value α x, the time that current control unit is in closed loop states can be shortened in the maximum copped wave angle namely reducing closed loop states namely, and then shortens invalid adjustment process.And reduce critical value α x, namely the maximum copped wave angle of closed loop states is reduced, need under equal copped wave corner condition, raise the value (because Vr is more high more close to critical condition) of control signal Vr, but, because current control unit is operated in closed loop states, therefore, the value of direct rising control signal Vr, the ON time Ton of main switch S1 can be made also temporarily to raise, the output current Io of pfc circuit raises, the output current sampled value of current control unit raises, the control signal Vr making it export reduces, therefore, direct rising control signal Vr can not make to enter critical condition under less copped wave angle α x.
Therefore, the embodiment of the present invention provides a kind of pfc circuit, load driving circuits and signal control method, can make in closed loop procedure, also namely described control signal is less than or equal in maximum range, the control signal rising that equal copped wave angle is corresponding, thus reduce critical value α x, realize the goal of the invention of the invalid adjustment process shortened in dimming process.
Below, the realization of embodiment of the present invention pfc circuit, load driving circuits and current control method is described with reference to the accompanying drawings.
See Fig. 5, be a kind of pfc circuit structural representation of the embodiment of the present invention, wherein:
The input of described pfc circuit receives chopping voltage, is also described input voltage vin; Described pfc circuit comprises: main switch S1 (not shown in Fig. 5) and Ton control unit 510; The control signal Vr that described Ton control unit 510 exports, being less than or equal in maximum range, with the copped wave angle positive correlation of described chopping voltage; (wherein, described positive correlation refers to: α is larger at copped wave angle, and described control signal Vr is also larger, and α is less at copped wave angle, and described control signal Vr is also less.)
Described pfc circuit also comprises:
Detecting compensating unit 520, for detecting the copped wave angle of chopping voltage, generating amplitude and the positively related compensating signal in copped wave angle; Control according to the comparison signal of described compensating signal to Ton control unit, make to be less than or equal in maximum range in described control signal, the control signal rising that equal copped wave angle is corresponding.Also namely, make under copped wave angle is constant, the control signal that current control circuit exports raises.
And then, by detecting the control of compensating unit 520 pairs of comparison signals, will new comparison signal be obtained, and Ton control unit is by according to new comparison signal, compares new comparison signal and control signal, determines the ON time Ton of main switch S1.
Here, described positive correlation refers to: copped wave angle is larger, and the amplitude of compensating signal is larger, and copped wave angle is less, then the amplitude of compensating signal is less.
Preferably, as shown in Figure 5, pfc circuit and the first rectifier can form load driving circuits, and the chopping voltage that this first rectifier is used for copped wave dimmer exports carries out rectification, thus obtains the input voltage vin of pfc circuit.
Wherein, as shown in Figure 5, two inputs detecting compensating unit 520 can connect two outputs of the first rectifier, the chopping voltage of the first rectifier output are carried out to the detection at copped wave angle;
Or also can arrange the second rectifier in addition, the second rectifier carries out rectification to the chopping voltage that copped wave dimmer exports; And two inputs detecting compensating unit 520 connect two outputs of the second rectifier, the chopping voltage of the second rectifier output is carried out to the detection at copped wave angle.
In the embodiment of the present invention, the chopping voltage that copped wave dimmer exports can be forward position chopping voltage, rear along chopping voltage or front and back along chopping voltage etc., does not limit here.
As shown in Figure 6, described detection compensating unit 520 can be realized by following structure:
Detection sub-unit 610, for detecting the copped wave angle of chopping voltage;
Generate subelement 620, for generating the positively related compensating signal of amplitude and copped wave angle;
Control subelement 630, for controlling according to the comparison signal of described compensating signal to Ton control unit.
Preferably, control subelement 630 specifically to may be used for: described compensating signal is added on the comparison signal of Ton control unit.
For the load driving circuits shown in Fig. 3, more specific detail is carried out to the pfc circuit of the embodiment of the present invention and load driving circuits.
In a kind of specific embodiment, described compensating signal can be current signal; Comparison signal can be sawtooth signal; Now, as shown in Figure 7:
Ton control unit comprises: the output of constant-current source Id is respectively by the first electric capacity C1 and second switch pipe S2 ground connection, first unearthed one end of electric capacity C1 is as comparison signal output, export comparison signal Vp, first unearthed one end of electric capacity C1 connects the inverting input of the first operational amplifier A 1; The normal phase input end of the first operational amplifier A 1 is used for reception control signal Vr, also namely connects the output of current control unit;
Wherein, when not comprising control subelement, the operation principle of Ton control unit is: when the S2 conducting of second switch pipe, voltage on first electric capacity C1 is zero, also namely comparison signal Vp is zero, when second switch pipe S2 turns off, constant-current source Id is that the first electric capacity C1 charges, voltage on first electric capacity C1 is started from scratch increase, namely also comparison signal Vp starts from scratch increase, when comparison signal Vp increases to equal with control signal Vr, and second switch pipe S2 conducting, therefore, the comparison signal Vp that first unearthed one end of electric capacity C1 exports is sawtooth waveforms.
As shown in Figure 7, control subelement 630 to comprise: two outputs generating subelement 620 connect the two ends of the first electric capacity C1 respectively.Thus, the compensating signal generating subelement 620 generation is converted to sawtooth signal in Ton control unit, and with described comparison signal same-phase, concrete: by two outputs generating subelement 620 being connected in parallel on the two ends of the first electric capacity C1, the voltage that the compensating signal generating subelement 620 output is produced at the two ends of the first electric capacity C1 is identical with the generation principle of comparison signal Vp, namely all controlled by second switch pipe S2, the voltage signal that compensating signal is produced on the first electric capacity C1 and comparison signal Vp same-phase, and the voltage on the first electric capacity C1 is the superposition of the two, and the slope of voltage Vp ' after superposition is greater than the slope of comparison signal Vp, with reference to Fig. 8.
Under the circuit structure shown in Fig. 7, as shown in Figure 8, it is sawtooth signal V α that compensating signal I α (not shown) is converted to a voltage signal on the first electric capacity C1 of Ton control unit, dotted line is comparison signal Vp, after the sawtooth signal V α that compensating signal I α produces superposes with comparison signal Vp, obtain new comparison signal Vp '=Vp+V α, as shown by the solid line in the drawings, and new comparison signal Vp ' will replace original comparison signal Vp to be input to the inverting input of the first operational amplifier to waveform.
New comparison signal Vp ', after comparing with current control signal Vr, obtain ON time Ton ', this ON time Ton ' is less than ON time Ton corresponding to comparison signal Vp, now, because current Ton ' diminishes, therefore, the output current Io of pfc circuit (being also load driving circuits) can diminish, current control unit diminishes to the output current Io sampled signal obtained of sampling, the control signal Vr that current control unit exports raises, and then the ON time Ton ' of main switch S1 is increased, the ON time maintaining main switch is constant, the output current Io maintaining pfc circuit (being also load driving circuits) is constant.
Therefore, when copped wave angle α is constant, when comparison signal becomes new comparison signal Vp ' from Vp, after input Ton control unit, the dynamic adjustments of current control unit finally makes the ON time Ton of main switch S1 constant, the output current Io of pfc circuit is constant, and control signal Vr is raised.Along with the increase of copped wave angle α, control signal Vr also can increase thereupon, and when Vr increases to Vr-max (corresponding copped wave angle is α x), current control unit is about to enter open loop situations.Also namely, make to be less than or equal in the scope of maximum Vr-max at described control signal Vr, the control signal Vr that equal copped wave angle α is corresponding raises, make under copped wave angle is constant, closer to closed loop open loop critical condition, thus reduce critical value α x, shorten the invalid adjustment process in dimming process.
In another kind of embodiment, described compensating signal V α can be voltage signal; Described comparison signal Vp can be sawtooth signal, and compensating signal V α can be level signal; Now, as shown in Figure 9:
Ton control unit comprises: the normal phase input end of the first operational amplifier A 1 is used for reception control signal;
Control subelement 630 to comprise:
First input end is for receiving comparison signal Vp, and first input end also connects the inverting input of the first operational amplifier A 1 by the first resistance R1; The compensating signal output generating subelement 620 connects the inverting input of the first operational amplifier A 1 by the second resistance R2.
Wherein, described comparison signal Vp can generate subelement by comparison signal as shown in Figure 7 and obtain, concrete, this comparison signal generates subelement and comprises: the output of constant-current source Id is respectively by the first electric capacity C1 and second switch pipe S2 ground connection, first unearthed one end of electric capacity C1 generates the comparison signal output of subelement as comparison signal, exports comparison signal Vp.
In fig .9, by the compensating signal V α of voltage signal form and comparison signal Vp, superposed by the first resistance R1 and the second resistance R2, obtain the new comparison signal Vp ' after superposing, be input to the inverting input of the first operational amplifier in Ton control unit.And, the DC offset voltage of new comparison signal Vp ' higher than the DC offset voltage of original comparison signal Vp, with reference to Figure 10.
In Fig. 10, compensating signal V α is level signal, and dotted line is comparison signal Vp, after compensating signal V α superposes with comparison signal Vp, obtains new comparison signal Vp '=Vp+V α, and as shown by the solid line in the drawings, its DC offset voltage raises waveform.
New comparison signal Vp ' compares with current control signal Vr by the first operational amplifier, the ON time Ton ' of the main switch drawn is less than ON time Ton corresponding to original comparison signal Vp, now, because the ON time Ton ' of current main switch diminishes, therefore, the output current Io of pfc circuit can diminish, current control unit diminishes to the output current Io sampled signal obtained of sampling, its control signal Vr exported raises, ON time Ton ' is increased, thus the output current Io maintaining pfc circuit is constant.
Therefore, when copped wave angle α is constant, after comparison signal becomes Vp ' from Vp, the dynamic adjustments of current control unit finally makes the ON time Ton of main switch constant, and the output current Io of pfc circuit is constant, and control signal Vr is raised.Along with the increase of copped wave angle α, control signal Vr also can increase thereupon, and when Vr increases to Vr-max, current control unit is about to enter open loop situations.Also namely, make to be less than or equal in the scope of maximum Vr-max at described control signal Vr, the control signal Vr that equal copped wave angle α is corresponding raises, make under copped wave angle is constant, closer to closed loop open loop critical condition, thus reduce critical value α x, shorten the invalid adjustment process in dimming process.
Wherein, the compensating signal in the embodiment of the present invention can be obtained by circuit structure as shown in figure 11, also namely detects the detection sub-unit 610 in compensating unit 520 and generate subelement 620 to be obtained by circuit structure as shown in figure 11.With reference to Figure 11:
Detection sub-unit 610 comprises:
The first input end of detection sub-unit 610 successively by the 3rd resistance R3 and the 4th resistance R4 ground connection, the second input end grounding of detection sub-unit (here indication " " be the output negative terminal of rectifier bridge in pfc circuit); 3rd resistance R3 is connected the base stage of the first triode Q1 with the tie point of the 4th resistance R4, the emitter grounding of the first triode Q1, and collector electrode connects the first output of detection sub-unit, the second output head grounding of detection sub-unit;
Generate subelement 620 to comprise:
The first input end generating subelement 620 connects the first output of detection sub-unit 610, and the second input generating subelement 620 connects the second output of detection sub-unit 610;
The first input end generating subelement 620 connects power source voltage Vcc by the 5th resistance R5, also by the second electric capacity C2 ground connection; Generate the first input end of subelement 620 successively by the first diode D1 and the 3rd electric capacity C3 ground connection; The negative electrode of the first diode D1 connects the base stage of the second triode Q2, and the emitter-base bandgap grading of the second triode Q2 is by the 6th resistance R6 ground connection, and the collector electrode of the second triode Q2 connects power source voltage Vcc;
Now, in generation subelement, the 6th resistance R6 two ends are as two outputs generating subelement, and the compensating signal of output is voltage signal;
Or, as shown in figure 11, the emitter-base bandgap grading of the second triode Q2 can connect one end of series arm, this series arm is the second diode D2 and the 7th resistance R7, now, the other end of series arm and the earth terminal of the 6th resistance R6 also can as two outputs generating subelement, and the compensating signal now exported is current signal.
In circuit shown in Figure 11, 3rd resistance R3 and the 4th resistance R4 is divider resistance, to what input, chopping voltage after rectification is sampled, by the first triode Q1, the low level signal in chopping voltage is detected, export sawtooth voltage, namely the voltage on the second electric capacity C2, the peak value of this sawtooth voltage increases along with the increase at copped wave angle, kept by the peak value of the first diode D1 and the 3rd electric capacity C3, 3rd electric capacity C3 obtains a level signal, the value of this level signal increases along with the increase at copped wave angle, by the follow circuit of the second triode Q2, voltage signal on the 6th resistance R6, also increase along with the increase at copped wave angle.The value of the current signal exported by the second diode D2 and the 7th resistance R7 is also increased along with the increase at copped wave angle.
Above-mentioned embodiment of the present invention pfc circuit can directly as load driving circuits, or, also can with the electrical combination such as the first rectifier, jointly form load driving circuits.
Corresponding with above-mentioned pfc circuit and load driving circuits, the embodiment of the present invention provides a kind of signal control method, and the method can be applied in pfc circuit, and the input of described pfc circuit receives chopping voltage; Described pfc circuit comprises: main switch and ton control unit; The control signal of described Ton control unit, being less than or equal in maximum range, with the copped wave angle positive correlation of described chopping voltage; (wherein, described positive correlation refers to: copped wave angle is larger, and described control signal Vr is also larger, and copped wave angle is less, and described control signal Vr is also less.)
As shown in figure 12, the method comprises:
Step 1201: the copped wave angle detecting chopping voltage;
Step 1202: generate amplitude and the positively related compensating signal in copped wave angle;
Step 1203: control according to the comparison signal of described compensating signal to Ton control unit, makes to be less than or equal in maximum range in described control signal, the control signal rising that equal copped wave angle is corresponding.
Preferably, describedly according to described compensating signal, control is carried out to the comparison signal of Ton control unit and can comprise: described compensating signal is added on the comparison signal of Ton control unit.
And then, in step 1203, will new comparison signal be obtained by described control; Afterwards, new comparison signal and control signal, by according to new comparison signal, compare by Ton control unit, determine the ON time Ton of main switch S1.
Based on above embodiment, detect the copped wave angle of chopping voltage, generate amplitude and the positively related compensating signal in copped wave angle; Control according to the comparison signal of described compensating signal to Ton control unit.Thus the comparison signal in Ton control unit is become new comparison signal, Ton control unit uses new comparison signal to compare with control signal, determine the ON time Ton of main switch, rising due to comparison signal makes the ON time Ton of main switch temporarily diminish, and then the output current that current control unit maintains ON time Ton and pfc circuit by closed-loop adjustment is constant, the control signal making identical copped wave angle corresponding raises, achieve the value raising control signal under the closed loop states of current control unit, thus reduce critical value α x, realize the goal of the invention of the invalid adjustment process shortened in dimming process.。
One of ordinary skill in the art will appreciate that, the process realizing the method for above-described embodiment can have been come by the hardware that program command is relevant, described program can be stored in read/write memory medium, and this program performs the corresponding step in said method when performing.Described storage medium can be as: ROM/RAM, magnetic disc, CD etc.
The above is only the preferred embodiment of the present invention; it should be pointed out that for those skilled in the art, under the premise without departing from the principles of the invention; can also make some improvements and modifications, these improvements and modifications also should be considered as protection scope of the present invention.
Claims (10)
1. a pfc circuit, is characterized in that, the input of described pfc circuit receives chopping voltage, and described pfc circuit comprises: main switch and Ton control unit; The control signal of described Ton control unit, being less than or equal in maximum range, with the copped wave angle positive correlation of described chopping voltage;
Described pfc circuit also comprises:
Detecting compensating unit, for detecting the copped wave angle of chopping voltage, generating amplitude and the positively related compensating signal in copped wave angle; Control according to the comparison signal of described compensating signal to Ton control unit, make to be less than or equal in maximum range in described control signal, the control signal rising that equal copped wave angle is corresponding.
2. circuit according to claim 1, is characterized in that, detects compensating unit and comprises:
Detection sub-unit, for detecting the copped wave angle of chopping voltage;
Generate subelement, for generating the positively related compensating signal of amplitude and copped wave angle;
Control subelement, for controlling according to the comparison signal of described compensating signal to Ton control unit.
3. circuit according to claim 2, is characterized in that, control subelement specifically for: described compensating signal is added on the comparison signal of Ton control unit.
4. circuit according to claim 3, is characterized in that, described compensating signal is current signal; Described comparison signal is sawtooth signal;
Ton control unit comprises: constant-current source is respectively by the first electric capacity and second switch pipe ground connection, and the unearthed first end of the first electric capacity connects the inverting input of the first operational amplifier; The normal phase input end of the first operational amplifier is used for reception control signal;
Control subelement comprises: two outputs generating subelement connect the two ends of the first electric capacity respectively.
5. circuit according to claim 3, is characterized in that, described compensating signal is voltage signal; Described comparison signal is sawtooth signal;
Ton control unit comprises: the normal phase input end of the first operational amplifier is used for reception control signal;
Control subelement comprises:
First input end is for receiving comparison signal, and first input end also connects the inverting input of the first operational amplifier by the first resistance; The compensating signal output generating subelement connects the inverting input of the first operational amplifier by the second resistance.
6. circuit according to claim 4, is characterized in that, described detection sub-unit comprises:
First input end passes through the 3rd resistance and the 4th grounding through resistance successively, the second input end grounding; 3rd resistance is connected the base stage of the first triode with the tie point of the 4th resistance, the grounded emitter of the first triode, and collector electrode connects the first output of detection sub-unit, the second output head grounding of detection sub-unit;
Generation subelement comprises:
The first input end generating subelement connects the first output of detection sub-unit, and the second input generating subelement connects the second output of detection sub-unit;
The first input end generating subelement connects supply voltage by the 5th resistance, also by the second capacity earth; Generate the first input end of subelement successively by the first diode and the 3rd capacity earth; The negative electrode of the first diode connects the base stage of the second triode, and the emitter of the second triode is by the 6th grounding through resistance, and the collector electrode of the second triode connects supply voltage; The emitter of the second triode is connected the compensating signal output generating subelement successively with the 7th resistance by the second diode.
7. circuit according to claim 5, is characterized in that, described detection sub-unit comprises: first input end passes through the 3rd resistance and the 4th grounding through resistance successively, the second input end grounding; 3rd resistance is connected the base stage of the first triode with the tie point of the 4th resistance, the grounded emitter of the first triode, and collector electrode connects the first output of detection sub-unit, the second output head grounding of detection sub-unit;
Generation subelement comprises:
The first input end generating subelement connects the first output of detection sub-unit, and the second input generating subelement connects the second output of detection sub-unit;
The first input end generating subelement connects supply voltage by the 5th resistance, also by the second capacity earth; Generate the first input end of subelement successively by the first diode and the 3rd capacity earth; The negative electrode of the first diode connects the base stage of the second triode, and the emitter of the second triode is by the 6th grounding through resistance, and the collector electrode of the second triode connects supply voltage; The emitter of the second triode is as the compensating signal output generating subelement.
8. a signal control method, is characterized in that, the method is applied to pfc circuit, and the input of described pfc circuit receives chopping voltage; Described pfc circuit comprises: main switch and Ton control unit; The control signal of described Ton control unit, being less than or equal in maximum range, with the copped wave angle positive correlation of described chopping voltage;
The method comprises:
Detect the copped wave angle of chopping voltage;
Generate amplitude and the positively related compensating signal in copped wave angle;
Control according to the comparison signal of described compensating signal to Ton control unit, make to be less than or equal in maximum range in described control signal, the control signal rising that equal copped wave angle is corresponding.
9. method according to claim 8, is characterized in that, carries out control comprise according to described compensating signal to the comparison signal of Ton control unit:
Described compensating signal is added on the comparison signal of Ton control unit.
10. a load driving circuits, is characterized in that, comprises the pfc circuit described in any one of claim 1 to 7.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201110376593.8A CN103138556B (en) | 2011-11-23 | 2011-11-23 | Pfc circuit, load driving circuits and signal control method |
| PCT/CN2012/078153 WO2013075504A1 (en) | 2011-11-23 | 2012-07-04 | Pfc circuit, load drive circuit and signal control method |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201110376593.8A CN103138556B (en) | 2011-11-23 | 2011-11-23 | Pfc circuit, load driving circuits and signal control method |
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| CN103138556A CN103138556A (en) | 2013-06-05 |
| CN103138556B true CN103138556B (en) | 2015-08-19 |
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| CN104219855B (en) * | 2014-09-28 | 2017-03-29 | 广东工业大学 | Based on APFC without stroboscopic LED constant current drive control circuit |
| CN104797041A (en) * | 2015-03-30 | 2015-07-22 | 成都颉隆科技有限公司 | Bootstrap trigger type smart grid frequency conversion energy-saving control system |
| CN104780670A (en) * | 2015-03-30 | 2015-07-15 | 成都颉隆科技有限公司 | Variable-frequency and energy-saving control system for smart power grid |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1106175A (en) * | 1993-09-07 | 1995-08-02 | 株式会社东芝 | Power conversion system |
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| CN101686587B (en) * | 2008-09-25 | 2015-01-28 | 皇家飞利浦电子股份有限公司 | Drive for providing variable power for LED array |
| TWI405502B (en) * | 2009-08-13 | 2013-08-11 | Novatek Microelectronics Corp | Dimmer circuit of light emitted diode and isolated voltage generator and dimmer method thereof |
| US8242766B2 (en) * | 2010-04-20 | 2012-08-14 | Power Integrations, Inc. | Dimming control for a switching power supply |
| TW201141303A (en) * | 2010-05-07 | 2011-11-16 | Light Engine Ltd | Triac dimmable power supply unit for LED |
| CN201995174U (en) * | 2011-01-28 | 2011-09-28 | 英飞特电子（杭州）有限公司 | Back-porch small-phase-angle light dimming circuit |
| CN102143638B (en) * | 2011-04-08 | 2013-07-24 | 矽力杰半导体技术(杭州)有限公司 | Silicon-controlled light-dimming circuit, light-dimming method and LED (light-emitting diode) driver applying the same |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1106175A (en) * | 1993-09-07 | 1995-08-02 | 株式会社东芝 | Power conversion system |
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| WO2013075504A1 (en) | 2013-05-30 |
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