CN204835912U - PFC circuit - Google Patents
PFC circuit Download PDFInfo
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- CN204835912U CN204835912U CN201520594895.6U CN201520594895U CN204835912U CN 204835912 U CN204835912 U CN 204835912U CN 201520594895 U CN201520594895 U CN 201520594895U CN 204835912 U CN204835912 U CN 204835912U
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Abstract
The utility model discloses a PFC circuit is through harmonic compensation sampling circuit PFC circuit's input voltage to carry out generating and exporting behind the differential differential signal vx, through zero passage compensating circuit in with the PFC main circuit current sample signal of switch tube pass through the peak holding, generate and export zero passage compensation signal, again with the PFC control circuit sampling the the first signal V1 stack of the electric current formation of switch tube is a comparison reference value and carries out the comparison with other signals, generates output the control signal of switch tube is because zero passage compensation signal's effect for the switch tube current signal of actually inputing comparison circuit reduces, and then makes near PFC circuit input voltage's zero passage, the turn -on time in every cycle of switch tube shortens, has reduced near zero passage the arrival current value of PFC main circuit has restrained the EMI problem owing to the electric current vibration arouses greatly.
Description
Technical field
The utility model relates to switch power technology field, particularly relates to a kind of pfc circuit.
Background technology
Traditional pfc circuit comprises: PFC main circuit and PFC control circuit.In prior art, in order to the high frequency reducing Switching Power On Electric Net pollutes, usually understand parallel filtering electric capacity (in as Fig. 1 the first electric capacity C1 and the second electric capacity C2) at the input of rectifier bridge and/or output; But due to the existence of filter capacitor, containing harmonic component in input current, make the phase place of total input current Iin can advanced input voltage vin, and then make the reduction of PF value or THD rising; Prior art improves PF value to reduce THD, usually in the pfc circuit of Switching Power Supply, increases harmonic compensation circuit, as shown in Figure 1.
But, when harmonic compensation circuit function, near the zero passage of input voltage vin, easily make the input current Iin of pfc circuit vibrate, as shown in Figure 2, cause serious EMI (ElectromagneticInterference, electromagnetic interference) problem.
Utility model content
In view of this, the utility model provides a kind of pfc circuit, to solve the EMI problem existed in prior art.
A kind of pfc circuit, be applied to Switching Power Supply, described pfc circuit comprises: PFC main circuit, PFC control circuit, harmonic compensation circuit and zero passage compensating circuit; Wherein:
The input of described zero passage compensating circuit is connected with the switching tube in described PFC main circuit, and the sampled signal for the electric current by described switching tube is kept by peak value, generates and exports zero passage compensating signal;
The input of described harmonic compensation circuit is connected with the input of described PFC main circuit, for the input voltage of described pfc circuit is carried out differential, generates and exports differential signal Vx;
Described PFC control circuit is connected with the input of the output of described switching tube, described harmonic compensation circuit, described PFC main circuit, the output of described zero passage compensating circuit and the output of described pfc circuit respectively, for:
Receive differential signal Vx, the electric current of described switching tube of sampling generates the first signal V1, sample described pfc circuit input voltage generate the 3rd signal V3, and the output current of described pfc circuit of sampling or output voltage generate sampled signal, compare with a reference signal again after described sampled signal is superposed with differential signal Vx, output feedback signal relatively, described feedback signal and the 3rd signal V3 carry out product calculation and generate secondary signal V2;
Receive described zero passage compensating signal, after being superposed with the first signal V1 by described zero passage compensating signal, compare base value as one and secondary signal V2 compares, generate and export the control signal of described switching tube.
Preferably, described PFC control circuit comprises: the first signal generating circuit, secondary signal produce circuit, comparison circuit, feedback signal generation circuit and turn-on control circuit; Wherein:
The first end of described first signal generating circuit is connected with described switching tube, described first end is also connected with the input of described zero passage compensating circuit, second end is connected with the output of described zero passage compensating circuit and an input of described comparison circuit, for sampling and generating according to the electric current of described switching tube and export the first signal V1;
The input that described secondary signal produces circuit is connected with the input of described PFC main circuit, for described pfc circuit of sampling input voltage and generate the 3rd signal V3, the output that another input produces circuit with described feedback signal is connected, for receiving described feedback signal, 3rd signal V3 and described feedback signal are input in multiplier and carry out product calculation by described secondary signal generation circuit, secondary signal V2 is generated after product, the output of described multiplier produces the output of circuit as described secondary signal and is connected with another input of described comparison circuit,
The output of described comparison circuit is all connected with the control end of described switching tube with the output of described turn-on control circuit; Described comparison circuit be used for when described compare base value be more than or equal to secondary signal V2 time, control described switching tube turn off;
Described feedback signal produces the input of circuit and is connected with the output of the output of described pfc circuit and described harmonic compensation circuit, for output current or the output voltage of described pfc circuit of sampling, and superpose with the differential signal Vx received, compare with described reference signal, export described feedback signal according to comparative result, the amplitude size of described feedback signal embodies the difference size of the output current of described pfc circuit or the sampled signal of output voltage and described reference signal.
Preferably, described zero passage compensating circuit comprises: diode, the 3rd resistance and the first electric capacity; Wherein:
The anode of described diode is the input of described zero passage compensating circuit;
The negative electrode of described diode is connected with one end of described 3rd resistance and described first electric capacity respectively;
The other end ground connection of described first electric capacity;
The other end of described 3rd resistance is the output of described zero passage compensating circuit.
Preferably, described harmonic compensation circuit comprises: the 3rd electric capacity and the 4th resistance; Wherein:
One end of described 3rd electric capacity is the input of described harmonic compensation circuit;
The other end of described 3rd electric capacity is connected with one end of described 4th resistance;
The other end of described 4th resistance is the output of described harmonic compensation circuit.
Preferably, described first signal generating circuit comprises: the first resistance and the second resistance, wherein:
One end ground connection of described first resistance, the other end is connected with described switching tube, the tie point of described first resistance and described switching tube is as the first end of the first signal generating circuit, described first end is connected with described second resistance one end, and the described second resistance other end is as the second end of the first signal generating circuit.
A kind of pfc circuit, be applied to Switching Power Supply, described pfc circuit comprises: PFC main circuit, PFC control circuit, harmonic compensation circuit and zero passage compensating circuit; Wherein:
The input of described zero passage compensating circuit is connected with the switching tube in described PFC main circuit, and the sampled signal for the electric current by described switching tube is kept by peak value, generates and exports zero passage compensating signal;
The input of described harmonic compensation circuit is connected with the input of described PFC main circuit, for the input voltage of described pfc circuit is carried out differential, generates and exports differential signal Vx;
Described PFC control circuit is connected with the output of described switching tube, described harmonic compensation circuit, the output of described zero passage compensating circuit and the output of described pfc circuit respectively, for:
Receive differential signal Vx, the output current of described pfc circuit of sampling or output voltage generate sampled signal, compare after described sampled signal being superposed with differential signal Vx with a reference signal again, export secondary signal V2 more afterwards;
Generate sawtooth signal and export as the first signal V1; Receive described zero passage compensating signal, after described zero passage compensating signal is superposed with the first signal V1, compare base value as one, compare with secondary signal V2, generate according to comparative result and export the control signal of described switching tube;
Or the output current of described pfc circuit of sampling or output voltage generate sampled signal, described sampled signal are compared with a reference signal, export secondary signal V2 more afterwards;
Generate sawtooth signal and export as the first signal V1; Receive described zero passage compensating signal and differential signal Vx, after described zero passage compensating signal is superposed with the first signal V1, compare base value as one, compare with secondary signal V2 again after superposing with differential signal Vx, generate according to comparative result and export the control signal of described switching tube.
Preferably, described PFC control circuit comprises: the first signal generating circuit, secondary signal produce circuit, comparison circuit and turn-on control circuit; Wherein:
The output of described first signal generating circuit is connected with the output of described zero passage compensating circuit, and tie point is connected with an input of described comparison circuit, for generating described sawtooth signal and exporting as the first signal V1;
The output of described comparison circuit is all connected with the control end of described switching tube with the output of described turn-on control circuit; Described comparison circuit be used for when described compare base value be more than or equal to secondary signal V2 time, control described switching tube turn off;
Described secondary signal produces the input of circuit and is connected with the output of the output of described pfc circuit and described harmonic compensation circuit, output is connected with another input of described comparison circuit, for output current or the output voltage of described pfc circuit of sampling, and superpose with the differential signal Vx received, compare with described reference signal, export secondary signal V2 to described comparison circuit according to comparative result.
Preferably, described PFC control circuit comprises: the first signal generating circuit, comparison circuit, secondary signal produce circuit and turn-on control circuit; Wherein:
The output of described first signal generating circuit is connected with the output of the output of described zero passage compensating circuit and described harmonic compensation circuit, tie point is connected with an input of described comparison circuit, for generating described sawtooth signal and exporting as the first signal V1;
The output of described comparison circuit is all connected with the control end of described switching tube with the output of described turn-on control circuit; Described comparison circuit be used for when described compare value that base value superposes with differential signal Vx be more than or equal to secondary signal V2 time, control the shutoff of described switching tube;
The input that described secondary signal produces circuit is connected with the output of described pfc circuit, output is connected with another input of described comparison circuit, for output current or the output voltage of described pfc circuit of sampling, and compare with described reference signal, export secondary signal V2 according to comparative result.
Preferably, described first signal generating circuit comprises: constant-current source and the first electric capacity; Wherein:
One end of described first electric capacity is connected with the output of described constant-current source, and tie point is the output of described first signal generating circuit;
The other end ground connection of described first electric capacity.
Preferably, described zero passage compensating circuit comprises: sampling resistor, the first resistance, the second electric capacity and diode; Wherein:
One end ground connection of described sampling resistor, the other end is connected with the anode of described switching tube and described diode, and tie point is the input of described zero passage compensating circuit;
The negative electrode of described diode is connected with one end of one end of described first resistance and described second electric capacity;
The other end of described first resistance is the output of described zero passage compensating circuit;
The other end ground connection of described second electric capacity.
Preferably, described harmonic compensation circuit comprises: the 3rd electric capacity and the second resistance; Wherein:
One end of described 3rd electric capacity is the input of described harmonic compensation circuit;
The other end of described 3rd electric capacity is connected with one end of described second resistance;
The other end of described second resistance is the output of described harmonic compensation circuit.
Preferably, described secondary signal generation circuit comprises: differential amplifier, compensating network and the 3rd resistance; Wherein:
One end of described 3rd resistance is connected with the output of described pfc circuit;
The described other end of the 3rd resistance is connected with the output of the inverting input of described differential amplifier and described harmonic compensation circuit;
The in-phase input end of described differential amplifier receives described reference signal;
Between the inverting input that described compensating network is connected to described differential amplifier and output;
The output of described differential amplifier is the output that described secondary signal produces circuit.
Preferably, described secondary signal generation circuit comprises: differential amplifier and compensating network; Wherein:
The inverting input of described differential amplifier is connected with the output of described pfc circuit;
The in-phase input end of described differential amplifier receives described reference signal;
Between the inverting input that described compensating network is connected to described differential amplifier and output;
The output of described differential amplifier is the output that described secondary signal produces circuit.
Pfc circuit disclosed in the utility model, by the input voltage of harmonic compensation circuit sampling pfc circuit, and generates after carrying out differential and exports differential signal Vx, kept by peak value by the current sampling signal of zero passage compensating circuit by PFC main circuit breaker in middle pipe, generate and export zero passage compensating signal, the first signal V1 that the electric current of sampling described switching tube with described PFC control circuit again generates is superposed to one and compares base value and other signals compare, generate and export the control signal of described switching tube, when described control signal is changed, sampling the value reduction of the first signal V1 generated according to the electric current of described switching tube, and then make near the zero passage of described pfc circuit input voltage, the ON time in each cycle of described switching tube shortens, reduce the input current value of described PFC main circuit near zero passage, greatly inhibit the EMI problem because current oscillation causes.
Accompanying drawing explanation
In order to be illustrated more clearly in the utility model embodiment or technical scheme of the prior art, be briefly described to the accompanying drawing used required in embodiment or description of the prior art below, apparently, accompanying drawing in the following describes is only embodiments more of the present utility model, for those of ordinary skill in the art, under the prerequisite not paying creative work, other accompanying drawing can also be obtained according to these accompanying drawings.
Fig. 1 is pfc circuit structural representation disclosed in prior art;
Fig. 2 is waveform input signal figure disclosed in prior art;
Fig. 3 is pfc circuit structural representation disclosed in the utility model embodiment;
Fig. 4 is another embodiment of the utility model another pfc circuit structural representation disclosed;
Fig. 5 is another embodiment of the utility model another pfc circuit structural representation disclosed;
Fig. 6 is another embodiment of the utility model another pfc circuit structural representation disclosed;
Fig. 7 is another embodiment of the utility model another pfc circuit structural representation disclosed;
Fig. 8 is another embodiment of the utility model another pfc circuit structural representation disclosed;
Fig. 9 is another embodiment of the utility model another pfc circuit structural representation disclosed.
Embodiment
Below in conjunction with the accompanying drawing in the utility model embodiment, be clearly and completely described the technical scheme in the utility model embodiment, obviously, described embodiment is only the utility model part embodiment, instead of whole embodiments.Based on the embodiment in the utility model, those of ordinary skill in the art are not making the every other embodiment obtained under creative work prerequisite, all belong to the scope of the utility model protection.
The utility model provides a kind of pfc circuit, is applied to Switching Power Supply, to solve the EMI problem existed in prior art.
Concrete, as shown in Figure 3, described pfc circuit comprises: PFC main circuit 101, PFC control circuit 102, harmonic compensation circuit 103 and zero passage compensating circuit 104; Wherein:
The input of zero passage compensating circuit 104 is connected with the switching tube in PFC main circuit 101;
The input of harmonic compensation circuit 103 is connected with the input of PFC main circuit 101;
PFC control circuit 102 is connected with the output of the output of described switching tube, harmonic compensation circuit 103, the input of PFC main circuit 101, the output of zero passage compensating circuit 104 and described pfc circuit respectively.
Concrete operation principle is:
The sampled signal of the electric current of described switching tube is kept by peak value by zero passage compensating circuit 104, generates and exports zero passage compensating signal;
The input voltage of described pfc circuit is carried out differential by harmonic compensation circuit 103, generates and exports differential signal Vx;
PFC control circuit 102 receives differential signal Vx, the electric current of described switching tube of sampling generates the first signal V1, sample described pfc circuit input voltage generate the 3rd signal V3, and the output current of described pfc circuit of sampling or output voltage generate sampled signal, after described sampled signal being superposed with differential signal Vx, a reference signal compares again, output feedback signal relatively, described feedback signal and the 3rd signal V3 carry out product calculation and generate secondary signal V2;
Receive described zero passage compensating signal, after being superposed with the first signal V1 by described zero passage compensating signal, compare base value as one and secondary signal V2 compares, generate and export the control signal of described switching tube.
Described pfc circuit disclosed in the present embodiment, generates after carrying out differential and export differential signal Vx by harmonic compensation circuit 103 to the input voltage of described pfc circuit, kept by peak value by the current sampling signal of zero passage compensating circuit 104 by PFC main circuit 101 breaker in middle pipe, generate and export described zero passage compensating signal, sample with PFC control circuit 102 again and be superposed to one according to the first signal V1 that the electric current of described switching tube generates and compare base value and other signals compare, generate and export the control signal of described switching tube, due to the effect of zero passage compensating signal, the actual switching tube current signal being input to comparison circuit is reduced, and then make near the zero passage of described pfc circuit input voltage, the ON time in each cycle of described switching tube shortens, reduce the input current value of PFC main circuit 101 near zero passage, greatly inhibit the EMI problem because current oscillation causes.
Preferably, as shown in Figure 4, PFC control circuit 102 comprises: the first signal generating circuit 201, secondary signal produce circuit 202, comparison circuit 203, feedback signal generation circuit 205 and turn-on control circuit 204; Wherein:
The first end of the first signal generating circuit 201 is connected with the input of described switching tube and zero passage compensating circuit 104, and the second end is connected with the output of zero passage compensating circuit 104 and an input of comparison circuit 203;
The input that secondary signal produces circuit 202 is connected with the input of PFC main circuit 101, and the output that another input produces circuit 205 with feedback signal is connected, and output is connected with another input of comparison circuit 203;
The output of comparison circuit 203 is all connected with the control end of described switching tube with the output of turn-on control circuit 204;
Feedback signal produces the input of circuit 205 and is connected with the output of the output of described pfc circuit and harmonic compensation circuit 103.
Concrete operation principle is:
First signal generating circuit 201 is for sampling and generating according to the electric current of described switching tube and export the first signal V1.
Feedback signal produces circuit 205 for the output current of described pfc circuit of sampling or output voltage, and is superposed by the differential signal Vx of reception, compares, according to comparative result output feedback signal with reference signal.
Secondary signal produces the input voltage of circuit 202 for described pfc circuit of sampling, receive described feedback signal, the 3rd signal V3 is generated again according to the input voltage of the described pfc circuit of sampling, and the 3rd signal V3 and described feedback signal are input in multiplier carry out product calculation, generate secondary signal V2 after product.
Comparison circuit 203 for when described compare base value be more than or equal to secondary signal V2 time, control described switching tube to turn off, now sampling the value of the first signal V1 generated according to the electric current of described switching tube reduce the occurrence of described zero passage compensating signal compared to existing technology, and then make near the zero passage of described pfc circuit input voltage, the ON time in each cycle of described switching tube shortens, reduce the input current value of PFC main circuit 101 near zero passage, greatly inhibit the EMI problem because current oscillation causes.
Preferably, as shown in Figure 5, the first signal generating circuit 201 comprises: the first resistance R1 and the second resistance R2; Wherein:
First resistance R1 is connected with one end of the second resistance R2, and tie point, as the first end of the first signal generating circuit 201, is connected with the tie point of described switching tube with the input of zero passage compensating circuit 104;
The other end ground connection of the first resistance R1;
The other end of the second resistance R2 is the second end of the first signal generating circuit 201.
Preferably, as shown in Figure 5, zero passage compensating circuit 104 comprises: diode D, the 3rd resistance R3 and the first electric capacity C1; Wherein:
The anode of described diode D is the input of zero passage compensating circuit 104;
The negative electrode of described diode D is connected with one end of the 3rd resistance R3 and the first electric capacity C1 respectively;
The other end ground connection of the first electric capacity C1;
The other end of the 3rd resistance R3 is the output of zero passage compensating circuit 104.
Preferably, as shown in Figure 5, secondary signal generation circuit 202 comprises: the 5th resistance R5, the 6th resistance R6 and multiplier; Wherein:
One end of 5th resistance R5 is connected with the input of PFC main circuit 101;
One end ground connection of the 6th resistance R6;
The other end of the 5th resistance R5 is connected with the other end of the 6th resistance R6, and tie point is connected with an input of described multiplier;
The output that another input and the feedback signal of described multiplier produce circuit 205 is connected, receiving feedback signals Vf, and output is the output that secondary signal produces circuit 202.
Preferably, as shown in Figure 5, feedback signal generation circuit 205 comprises: differential amplifier, compensating network and the 7th resistance R7; Wherein:
One end of 7th resistance R7 is connected with the output of described pfc circuit, the output current of described pfc circuit of sampling or output voltage Io/Vo;
The other end of the 7th resistance R7 is connected with the output of the inverting input of described differential amplifier and harmonic compensation circuit 103;
The in-phase input end of described differential amplifier receives reference signal Iref/Vref;
Between the inverting input that described compensating network is parallel to described differential amplifier and output;
The output of described differential amplifier is the output that feedback signal produces circuit 205.
Preferably, as shown in Figure 5, harmonic compensation circuit 103 comprises: the 3rd electric capacity C3 and the 4th resistance R4; Wherein:
One end of 3rd electric capacity C3 is the input of harmonic compensation circuit 103;
The other end of the 3rd electric capacity C3 is connected with one end of the 4th resistance R4;
The other end of the 4th resistance R4 is the output of harmonic compensation circuit 103, exports differential signal Vx.
The first end of the first signal generating circuit 201 shown in Fig. 5, be connected with the tie point of described switching tube with the input of zero passage compensating circuit 104, for the electric current of described switching tube of sampling, voltage signal on the first resistance R1 connected with the switching tube in PFC main circuit 101 can embody the size of current of described switching tube, and the first signal V1 that corresponding first signal generating circuit 201 exports is the current sampling signal of described switching tube.
In harmonic compensation circuit 103, input voltage signal is converted to harmonic current (i.e. differential signal Vx) by the series arm of RC through differential, then harmonic current (differential signal Vx) is injected in feedback signal generation circuit 205.
The secondary signal V2 that secondary signal generation circuit 202 exports is the product of input voltage sampled signal Vi and feedback signal Vf.In concrete practical application, the superposition value of output current or output voltage signal Io/Vo and differential signal Vx, then after comparing with reference signal Iref/Vref, be feedback signal according to the error amplification signal that comparative result exports.
Zero passage compensating circuit 101 is by the peak holding circuit of diode D and the first electric capacity C1, obtain the peak signal of current sampling signal, and by the second resistance R2 in the 3rd resistance R3 and the first signal generating circuit 201, the described zero passage compensating signal exported by zero passage compensating circuit 104 superposes with the first signal V1, is input in comparison circuit 203 after superposition.When the first signal V1 is the current sampling signal of described switching tube, the described zero passage compensating signal that zero passage compensating circuit 104 exports is voltage signal accordingly, and the signal that the peak value that the signal obtained after superposing with the first signal V1 is described current sampling signal changes according to the output signal of zero passage compensating circuit 104.
The utility model another embodiment still provides a kind of pfc circuit, as shown in Figure 3, described pfc circuit comprises: PFC main circuit 101, PFC control circuit 102, harmonic compensation circuit 103 and zero passage compensating circuit 104; Wherein:
The input of zero passage compensating circuit 104 is connected with the switching tube in PFC main circuit 101;
The input of harmonic compensation circuit 103 is connected with the input of PFC main circuit 101;
PFC control circuit 102 is connected with the output of the output of described switching tube, harmonic compensation circuit 103, the output of zero passage compensating circuit 104 and described pfc circuit respectively.
Concrete operation principle is:
The sampled signal of the electric current of described switching tube is kept by peak value by zero passage compensating circuit 104, generates and exports zero passage compensating signal;
The input voltage of described pfc circuit is carried out differential by harmonic compensation circuit 103, generates and exports differential signal Vx;
PFC control circuit 102 receives differential signal Vx, and the output current of described pfc circuit of sampling or output voltage generate sampled signal, compare after described sampled signal being superposed with differential signal Vx with a reference signal again, export secondary signal V2 more afterwards; Generate sawtooth signal and export as the first signal V1; Receive described zero passage compensating signal, after described zero passage compensating signal is superposed with the first signal V1, compare base value as one, compare with secondary signal V2, generate according to comparative result and export the control signal of described switching tube;
Or the sample output current of described pfc circuit or output voltage of PFC control circuit 102 generates sampled signal, described sampled signal is compared with a reference signal, more afterwards output secondary signal V2; Generate sawtooth signal and export as the first signal V1; Receive described zero passage compensating signal and differential signal Vx, after described zero passage compensating signal is superposed with the first signal V1, compare base value as one, compare with secondary signal V2 again after superposing with differential signal Vx, generate according to comparative result and export the control signal of described switching tube.
Described pfc circuit disclosed in the present embodiment, generates after carrying out differential and export differential signal Vx by harmonic compensation circuit 103 to the input voltage of described pfc circuit, kept by peak value by the current sampling signal of zero passage compensating circuit 104 by PFC main circuit 101 breaker in middle pipe, generate and export described zero passage compensating signal, to generate with PFC control circuit 102 again and the first signal V1 exported is superposed to one compares base value and other signals compare, generate and export the control signal of described switching tube, when described control signal is changed, sampling the value reduction of the first signal V1 generated according to the electric current of described switching tube, and then make near the zero passage of described pfc circuit input voltage, the ON time in each cycle of described switching tube shortens, reduce the input current value of PFC main circuit 101 near zero passage, greatly inhibit the EMI problem because current oscillation causes.
Preferably, as shown in Figure 6, PFC control circuit 102 comprises: the first signal generating circuit 201, comparison circuit 203, secondary signal produce circuit 205 and turn-on control circuit 204; Wherein:
The output of the first signal generating circuit 201 is connected with the output of zero passage compensating circuit 104, and tie point is connected with an input of comparison circuit 203;
The output of comparison circuit 203 is all connected with the control end of described switching tube with the output of turn-on control circuit 204;
Secondary signal produces the input of circuit 205 and is connected with the output of the output of described pfc circuit and harmonic compensation circuit 103, and output is connected with another input of comparison circuit 203.
Concrete operation principle is:
First signal generating circuit 201 is for generating described sawtooth signal and exporting as the first signal V1;
Comparison circuit 203 for when described compare base value be more than or equal to secondary signal V2 time, control described switching tube turn off;
Secondary signal produces circuit 205 for the output current of described pfc circuit of sampling or output voltage, and superposes with the differential signal Vx received, and compares with described reference signal, exports secondary signal V2 according to comparative result.
Preferably, as shown in Figure 7, the first signal generating circuit 201 comprises: constant-current source Id and the first electric capacity C1; Wherein:
One end of first electric capacity C1 is connected with the output of constant-current source Id, and tie point is the output of the first signal generating circuit 201;
The other end ground connection of the first electric capacity C1.
Preferably, as shown in Figure 7, zero passage compensating circuit 104 comprises: sampling resistor Rs, the first resistance R1, the second electric capacity C2 and diode D; Wherein:
One end ground connection of sampling resistor Rs, the other end is connected with the anode of described switching tube and diode D, and tie point is the input of zero passage compensating circuit 104;
The negative electrode of diode D is connected with one end of one end of the first resistance R1 and the second electric capacity C2;
The other end of the first resistance R1 is the output of zero passage compensating circuit 104;
The other end ground connection of the second electric capacity C2.
Preferably, as shown in Figure 7, secondary signal generation circuit 205 comprises: differential amplifier, compensating network and the 3rd resistance R3; Wherein:
One end of 3rd resistance R3 is connected with the output of described pfc circuit, the output current of described pfc circuit of sampling or output voltage Io/Vo;
The other end of the 3rd resistance R3 is connected with the output of the inverting input of described differential amplifier and harmonic compensation circuit 103;
The in-phase input end of described differential amplifier receives reference signal Iref/Vref;
Between the inverting input that described compensating network is parallel to described differential amplifier and output;
The output of described differential amplifier is the output that secondary signal produces circuit 205.
Preferably, as shown in Figure 7, harmonic compensation circuit 103 comprises: the 3rd electric capacity C3 and the second resistance R2; Wherein:
One end of 3rd electric capacity C3 is the input of harmonic compensation circuit 103;
The other end of the 3rd electric capacity C3 is connected with one end of the second resistance R2;
The other end of the second resistance R2 is the output of harmonic compensation circuit 103, exports differential signal Vx.
The first signal generating circuit 201 as shown in Figure 7 generates the described sawtooth signal of fixed slope, and secondary signal produces circuit 205 and exports secondary signal V2.
To be sampled by sampling resistor Rs the electric current of described switching tube, again by the peak holding circuit of diode D and the second electric capacity C2, obtain the peak signal of current sampling signal, and by the first resistance R1, the first signal V1 that the described zero passage compensating signal sampled signal of the electric current of described switching tube and zero passage compensating circuit 104 exported and the first signal generating circuit 201 export superposes, and is input in comparison circuit 203 after superposition; The signal obtained after the described zero passage compensating signal that sampled signal and the zero passage compensating circuit 104 of the electric current of described switching tube export and the first signal V1 that the first signal generating circuit 201 exports superpose is: the signal that sawtooth waveforms slope changes according to the output signal of zero passage compensating circuit 104.
The utility model another embodiment still provides a kind of pfc circuit, as shown in Figure 3, described pfc circuit comprises: PFC main circuit 101, PFC control circuit 102, harmonic compensation circuit 103 and zero passage compensating circuit 104; Wherein:
The input of zero passage compensating circuit 104 is connected with the switching tube in PFC main circuit 101;
The input of harmonic compensation circuit 103 is connected with the input of PFC main circuit 101;
PFC control circuit 102 is connected with the output of the output of described switching tube, harmonic compensation circuit 103, the output of zero passage compensating circuit 104 and described pfc circuit respectively.
Concrete operation principle is same as the previously described embodiments, repeats no more herein.
Preferably, as shown in Figure 8, PFC control circuit 102 comprises: the first signal generating circuit 201, comparison circuit 203, secondary signal produce circuit 205 and turn-on control circuit 204; Wherein:
The output of the first signal generating circuit 201 is connected with the output of the output of zero passage compensating circuit 104 and harmonic compensation circuit 103, and tie point is connected with an input of comparison circuit 203;
The output of comparison circuit 203 is all connected with the control end of described switching tube with the output of turn-on control circuit 204;
The input that secondary signal produces circuit 205 is connected with the output of described pfc circuit, and output is connected with another input of comparison circuit 203.
Concrete operation principle is:
First signal generating circuit 201 is for generating described sawtooth signal and exporting as the first signal V1;
Comparison circuit 203 for when described compare value that base value superposes with differential signal Vx be more than or equal to secondary signal V2 time, control described switching tube and turn off;
Secondary signal produces circuit 205 for the output current of described pfc circuit of sampling or output voltage, and compares with described reference signal, exports secondary signal V2 according to comparative result.
Preferably, as shown in Figure 9, the first signal generating circuit 201 comprises: constant-current source Id and the first electric capacity C1; Wherein:
One end of first electric capacity C1 is connected with the output of constant-current source Id, and tie point is the output of the first signal generating circuit 201;
The other end ground connection of the first electric capacity C1.
Preferably, as shown in Figure 9, zero passage compensating circuit 104 comprises: sampling resistor Rs, the first resistance R1, the second electric capacity C2 and diode D; Wherein:
One end ground connection of sampling resistor Rs, the other end is connected with the anode of described switching tube and diode D, and tie point is the input of zero passage compensating circuit 104;
The negative electrode of diode D is connected with one end of one end of the first resistance R1 and the second electric capacity C2;
The other end of the first resistance R1 is the output of zero passage compensating circuit 104;
The other end ground connection of the second electric capacity C2.
Preferably, as shown in Figure 9, the output of harmonic compensation circuit 103 is connected with the output of the first signal generating circuit 201; Harmonic compensation circuit 103 comprises: the 3rd electric capacity C3 and the second resistance R2; Wherein:
One end of 3rd electric capacity C3 is the input of harmonic compensation circuit 103;
The other end of the 3rd electric capacity C3 is connected with one end of the second resistance R2;
The other end of the second resistance R2 is the output of harmonic compensation circuit 103, exports differential signal Vx.
Preferably, as shown in Figure 9, secondary signal generation circuit 205 comprises: differential amplifier and compensating network; Wherein:
The inverting input of described differential amplifier is be connected with the output of described pfc circuit, the output current of described pfc circuit of sampling or output voltage Io/Vo;
The in-phase input end of described differential amplifier receives reference signal Iref/Vref;
Between the inverting input that described compensating network is parallel to described differential amplifier and output;
The output of described differential amplifier is the output that secondary signal produces circuit 205.
The first signal generating circuit 201 as shown in Figure 9 generates the sawtooth signal of fixed slope, produced by the constant-current source Id of the first signal generating circuit 201 and the first electric capacity C1, concrete, constant-current source Id is that the first electric capacity C1 charges, and the voltage signal on the first electric capacity C1 is sawtooth signal.Secondary signal produces circuit 205 and exports secondary signal V2.
The input voltage signal of sampling is converted to harmonic current (i.e. differential signal Vx) by the series arm of RC by harmonic compensation circuit 103, again harmonic current (differential signal Vx) is injected into the output of the first signal generating circuit 201, be that the first electric capacity C1 charges together with current source Id, the voltage signal on the first electric capacity C1 obtained is input in comparison circuit 203.
To be sampled by sampling resistor Rs the electric current of described switching tube, again by the peak holding circuit of diode D and the second electric capacity C2, obtain the peak signal of current sampling signal, and by the first resistance R1, the first signal V1 that the described zero passage compensating signal sampled signal of the electric current of described switching tube and zero passage compensating circuit 104 exported and the first signal generating circuit 201 export superposes, and is input in comparison circuit 203 after superposition; The signal obtained after the described zero passage compensating signal that sampled signal and the zero passage compensating circuit 104 of the electric current of described switching tube export and the first signal V1 that the first signal generating circuit 201 exports superpose is: the signal that sawtooth waveforms slope changes according to the output signal of zero passage compensating circuit 104.
Preferably, shown in as arbitrary in Fig. 5, Fig. 7 and Fig. 9, comparison circuit 203 is comparator; The inverting input of described comparator is connected with the output of zero passage compensating circuit 104.
Shown in Fig. 5, Fig. 7 and Fig. 9 are arbitrary, the object of described comparator is: when the signal that described in-phase input end receives is less than the signal of described inverting input reception, controls described switching tube and turn off; Described switching tube conducting is controlled again by the predetermined time of turn-on control circuit 204 after described switching tube turns off.
In this specification, each embodiment adopts the mode of going forward one by one to describe, and what each embodiment stressed is the difference with other embodiments, between each embodiment identical similar portion mutually see.
To the above-mentioned explanation of the disclosed embodiments, professional and technical personnel in the field are realized or uses the utility model.To be apparent for those skilled in the art to the multiple amendment of these embodiments, General Principle as defined herein when not departing from spirit or scope of the present utility model, can realize in other embodiments.Therefore, the utility model can not be restricted to these embodiments shown in this article, but will meet the widest scope consistent with principle disclosed herein and features of novelty.
Claims (13)
1. a pfc circuit, is characterized in that, is applied to Switching Power Supply, and described pfc circuit comprises: PFC main circuit, PFC control circuit, harmonic compensation circuit and zero passage compensating circuit; Wherein:
The input of described zero passage compensating circuit is connected with the switching tube in described PFC main circuit, and the sampled signal for the electric current by described switching tube is kept by peak value, generates and exports zero passage compensating signal;
The input of described harmonic compensation circuit is connected with the input of described PFC main circuit, for the input voltage of described pfc circuit is carried out differential, generates and exports differential signal Vx;
Described PFC control circuit is connected with the input of the output of described switching tube, described harmonic compensation circuit, described PFC main circuit, the output of described zero passage compensating circuit and the output of described pfc circuit respectively, for:
Receive differential signal Vx, the electric current of described switching tube of sampling generates the first signal V1, sample described pfc circuit input voltage generate the 3rd signal V3, and the output current of described pfc circuit of sampling or output voltage generate sampled signal, compare with a reference signal again after described sampled signal is superposed with differential signal Vx, output feedback signal relatively, described feedback signal and the 3rd signal V3 carry out product calculation and generate secondary signal V2;
Receive described zero passage compensating signal, after being superposed with the first signal V1 by described zero passage compensating signal, compare base value as one and secondary signal V2 compares, generate and export the control signal of described switching tube.
2. pfc circuit according to claim 1, is characterized in that, described PFC control circuit comprises: the first signal generating circuit, secondary signal produce circuit, comparison circuit, feedback signal generation circuit and turn-on control circuit; Wherein:
The first end of described first signal generating circuit is connected with described switching tube, described first end is also connected with the input of described zero passage compensating circuit, second end is connected with the output of described zero passage compensating circuit and an input of described comparison circuit, for sampling and generating according to the electric current of described switching tube and export the first signal V1;
The input that described secondary signal produces circuit is connected with the input of described PFC main circuit, for described pfc circuit of sampling input voltage and generate the 3rd signal V3, the output that another input produces circuit with described feedback signal is connected, for receiving described feedback signal, 3rd signal V3 and described feedback signal are input in multiplier and carry out product calculation by described secondary signal generation circuit, secondary signal V2 is generated after product, the output of described multiplier produces the output of circuit as described secondary signal and is connected with another input of described comparison circuit,
The output of described comparison circuit is all connected with the control end of described switching tube with the output of described turn-on control circuit; Described comparison circuit be used for when described compare base value be more than or equal to secondary signal V2 time, control described switching tube turn off;
Described feedback signal produces the input of circuit and is connected with the output of the output of described pfc circuit and described harmonic compensation circuit, for output current or the output voltage of described pfc circuit of sampling, and superpose with the differential signal Vx received, compare with described reference signal, export described feedback signal according to comparative result, the amplitude size of described feedback signal embodies the difference size of the output current of described pfc circuit or the sampled signal of output voltage and described reference signal.
3. pfc circuit according to claim 2, is characterized in that, described zero passage compensating circuit comprises: diode, the 3rd resistance and the first electric capacity; Wherein:
The anode of described diode is the input of described zero passage compensating circuit;
The negative electrode of described diode is connected with one end of described 3rd resistance and described first electric capacity respectively;
The other end ground connection of described first electric capacity;
The other end of described 3rd resistance is the output of described zero passage compensating circuit.
4. pfc circuit according to claim 2, is characterized in that, described harmonic compensation circuit comprises: the 3rd electric capacity and the 4th resistance; Wherein:
One end of described 3rd electric capacity is the input of described harmonic compensation circuit;
The other end of described 3rd electric capacity is connected with one end of described 4th resistance;
The other end of described 4th resistance is the output of described harmonic compensation circuit.
5. pfc circuit according to claim 2, is characterized in that, described first signal generating circuit comprises: the first resistance and the second resistance, wherein:
One end ground connection of described first resistance, the other end is connected with described switching tube, the tie point of described first resistance and described switching tube is as the first end of the first signal generating circuit, described first end is connected with described second resistance one end, and the described second resistance other end is as the second end of the first signal generating circuit.
6. a pfc circuit, is characterized in that, is applied to Switching Power Supply, and described pfc circuit comprises: PFC main circuit, PFC control circuit, harmonic compensation circuit and zero passage compensating circuit; Wherein:
The input of described zero passage compensating circuit is connected with the switching tube in described PFC main circuit, and the sampled signal for the electric current by described switching tube is kept by peak value, generates and exports zero passage compensating signal;
The input of described harmonic compensation circuit is connected with the input of described PFC main circuit, for the input voltage of described pfc circuit is carried out differential, generates and exports differential signal Vx;
Described PFC control circuit is connected with the output of described switching tube, described harmonic compensation circuit, the output of described zero passage compensating circuit and the output of described pfc circuit respectively, for:
Receive differential signal Vx, the output current of described pfc circuit of sampling or output voltage generate sampled signal, compare after described sampled signal being superposed with differential signal Vx with a reference signal again, export secondary signal V2 more afterwards;
Generate sawtooth signal and export as the first signal V1; Receive described zero passage compensating signal, after described zero passage compensating signal is superposed with the first signal V1, compare base value as one, compare with secondary signal V2, generate according to comparative result and export the control signal of described switching tube;
Or the output current of described pfc circuit of sampling or output voltage generate sampled signal, described sampled signal are compared with a reference signal, export secondary signal V2 more afterwards;
Generate sawtooth signal and export as the first signal V1; Receive described zero passage compensating signal and differential signal Vx, after described zero passage compensating signal is superposed with the first signal V1, compare base value as one, compare with secondary signal V2 again after superposing with differential signal Vx, generate according to comparative result and export the control signal of described switching tube.
7. pfc circuit according to claim 6, is characterized in that, described PFC control circuit comprises: the first signal generating circuit, secondary signal produce circuit, comparison circuit and turn-on control circuit; Wherein:
The output of described first signal generating circuit is connected with the output of described zero passage compensating circuit, and tie point is connected with an input of described comparison circuit, for generating described sawtooth signal and exporting as the first signal V1;
The output of described comparison circuit is all connected with the control end of described switching tube with the output of described turn-on control circuit; Described comparison circuit be used for when described compare base value be more than or equal to secondary signal V2 time, control described switching tube turn off;
Described secondary signal produces the input of circuit and is connected with the output of the output of described pfc circuit and described harmonic compensation circuit, output is connected with another input of described comparison circuit, for output current or the output voltage of described pfc circuit of sampling, and superpose with the differential signal Vx received, compare with described reference signal, export secondary signal V2 to described comparison circuit according to comparative result.
8. pfc circuit according to claim 6, is characterized in that, described PFC control circuit comprises: the first signal generating circuit, comparison circuit, secondary signal produce circuit and turn-on control circuit; Wherein:
The output of described first signal generating circuit is connected with the output of the output of described zero passage compensating circuit and described harmonic compensation circuit, tie point is connected with an input of described comparison circuit, for generating described sawtooth signal and exporting as the first signal V1;
The output of described comparison circuit is all connected with the control end of described switching tube with the output of described turn-on control circuit; Described comparison circuit be used for when described compare value that base value superposes with differential signal Vx be more than or equal to secondary signal V2 time, control the shutoff of described switching tube;
The input that described secondary signal produces circuit is connected with the output of described pfc circuit, output is connected with another input of described comparison circuit, for output current or the output voltage of described pfc circuit of sampling, and compare with described reference signal, export secondary signal V2 according to comparative result.
9. the pfc circuit according to claim 7 or 8, is characterized in that, described first signal generating circuit comprises: constant-current source and the first electric capacity; Wherein:
One end of described first electric capacity is connected with the output of described constant-current source, and tie point is the output of described first signal generating circuit;
The other end ground connection of described first electric capacity.
10. the pfc circuit according to claim 7 or 8, is characterized in that, described zero passage compensating circuit comprises: sampling resistor, the first resistance, the second electric capacity and diode; Wherein:
One end ground connection of described sampling resistor, the other end is connected with the anode of described switching tube and described diode, and tie point is the input of described zero passage compensating circuit;
The negative electrode of described diode is connected with one end of one end of described first resistance and described second electric capacity;
The other end of described first resistance is the output of described zero passage compensating circuit;
The other end ground connection of described second electric capacity.
11. pfc circuits according to claim 7 or 8, it is characterized in that, described harmonic compensation circuit comprises: the 3rd electric capacity and the second resistance; Wherein:
One end of described 3rd electric capacity is the input of described harmonic compensation circuit;
The other end of described 3rd electric capacity is connected with one end of described second resistance;
The other end of described second resistance is the output of described harmonic compensation circuit.
12. pfc circuits according to claim 7, is characterized in that, described secondary signal produces circuit and comprises: differential amplifier, compensating network and the 3rd resistance; Wherein:
One end of described 3rd resistance is connected with the output of described pfc circuit;
The described other end of the 3rd resistance is connected with the output of the inverting input of described differential amplifier and described harmonic compensation circuit;
The in-phase input end of described differential amplifier receives described reference signal;
Between the inverting input that described compensating network is connected to described differential amplifier and output;
The output of described differential amplifier is the output that described secondary signal produces circuit.
13. pfc circuits according to claim 8, is characterized in that, described secondary signal produces circuit and comprises: differential amplifier and compensating network; Wherein:
The inverting input of described differential amplifier is connected with the output of described pfc circuit;
The in-phase input end of described differential amplifier receives described reference signal;
Between the inverting input that described compensating network is connected to described differential amplifier and output;
The output of described differential amplifier is the output that described secondary signal produces circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201520594895.6U CN204835912U (en) | 2015-08-07 | 2015-08-07 | PFC circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201520594895.6U CN204835912U (en) | 2015-08-07 | 2015-08-07 | PFC circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN204835912U true CN204835912U (en) | 2015-12-02 |
Family
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201520594895.6U Withdrawn - After Issue CN204835912U (en) | 2015-08-07 | 2015-08-07 | PFC circuit |
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|---|---|
| CN (1) | CN204835912U (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104993692A (en) * | 2015-08-07 | 2015-10-21 | 英飞特电子（杭州）股份有限公司 | PFC circuit |
| CN107121400A (en) * | 2017-06-16 | 2017-09-01 | 珠海任驰光电科技有限公司 | A kind of pseudo-differential wavelength modulation optical fiber concentration of methane gas detection means and method |
| WO2018006767A1 (en) * | 2016-07-08 | 2018-01-11 | 张玉清 | Induction cooktop having adjustable continuous power |
-
2015
- 2015-08-07 CN CN201520594895.6U patent/CN204835912U/en not_active Withdrawn - After Issue
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104993692A (en) * | 2015-08-07 | 2015-10-21 | 英飞特电子（杭州）股份有限公司 | PFC circuit |
| CN104993692B (en) * | 2015-08-07 | 2017-07-14 | 英飞特电子（杭州）股份有限公司 | A kind of pfc circuit |
| WO2018006767A1 (en) * | 2016-07-08 | 2018-01-11 | 张玉清 | Induction cooktop having adjustable continuous power |
| CN107121400A (en) * | 2017-06-16 | 2017-09-01 | 珠海任驰光电科技有限公司 | A kind of pseudo-differential wavelength modulation optical fiber concentration of methane gas detection means and method |
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