CN203368837U - Circuit for reducing ripple current of LED - Google Patents
Circuit for reducing ripple current of LED Download PDFInfo
- Publication number
- CN203368837U CN203368837U CN2013203728187U CN201320372818U CN203368837U CN 203368837 U CN203368837 U CN 203368837U CN 2013203728187 U CN2013203728187 U CN 2013203728187U CN 201320372818 U CN201320372818 U CN 201320372818U CN 203368837 U CN203368837 U CN 203368837U
- Authority
- CN
- China
- Prior art keywords
- signal
- resistance
- circuit
- operational amplifier
- output
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn - After Issue
Links
Images
Classifications
-
- 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
- Y02B20/40—Control techniques providing energy savings, e.g. smart controller or presence detection
Landscapes
- Led Devices (AREA)
Abstract
The utility model discloses a circuit for reducing ripple current of an LED, which can perform further optimization on the output of an existing LED driving plan. Particularly, the circuit dynamically adjusts the voltage at one end of an LED light source through detecting the output voltage ripple of the existing LED driving plan, so that the voltage at one end of the LED light source changes proportionally with the voltage change at the other end. Finally a fact that the ripple voltage at two ends of the LED light source is nearly zero is realized, and furthermore the ripple current of the LED light source is nearly zero. Through the circuit provided by the utility model, the brightness of the LED light source can be kept constant. Even the human eyes are in the lighting environment for a long time period, no remarkable fatigue feeling is caused.
Description
Technical field
The present invention relates to a kind of power control circuit, particularly relate to a kind of for reducing the circuit of LED ripple current.
Background technology
When Switching Power Supply is used for the driving LED light-emitting diode, for making the LED light-emitting diode luminance, keep constant, require the LED driving power to there is the function of constant current output.In addition, for the power factor of the LED light emitting diode bulb of incoming transport electrical network, certain requirement is arranged, because if power factor does not reach requirement, can cause pollution to a certain degree to electrical network.IEC International Electrotechnical Commission has proposed clear and definite harmonic requirement to lighting, i.e. the IEC61000-3-2 standard; The accurate regulation of the asterisk of american energy, the LED light emitting diode bulb that is greater than 5W for power requires power factor to be not less than 0.7; The European standard regulation, require power factor higher than 0.9 for the LED light emitting diode bulb that is greater than 25W.From the situation of practical application, to the requirement of power factor mostly higher than the regulation of above-mentioned standard.
The existing the simplest driving power that can simultaneously meet High Power Factor and wide AC-input voltage scope constant current output function is based on the power factor correction (PFC of reverse exciting topological, Power Factor Correction) circuit, be called for short the single-stage pfc circuit, above-mentioned single-stage pfc circuit can be realized the power factor correction of input current and the adjustment of output current simultaneously.
Fig. 1 is existing more common a LED drive scheme, and Fig. 2 is the rough schematic view of coherent signal waveform in circuit shown in Fig. 1.In order to meet in relevant criterion, for the requirement of power factor and harmonic current.This scheme has adopted single-stage pfc circuit structure, and it comprises: rectifier bridge 101; Input capacitance 102; Absorbing circuit 104; The transformer 105 formed by armature winding 106, auxiliary winding 107 and secondary winding 108; Secondary commutation diode 109; Output capacitance 110; LED load 111; Controller circuitry 103; Switching tube 112; Sampling resistor 113.
In the application of above-mentioned Fig. 1, the alternating voltage of input, after described rectifier bridge 101, is exported the voltage signal after rectification 120 of one-period, and the phase place of described voltage signal 120 after rectification is identical with the phase place of input ac voltage; Simultaneously, control chip in this controller circuitry 103 of described controller circuitry 103(can be selected existing chip, such as GL8259, BP3319 etc.) the turning on and off of control switch pipe 112, the voltage signal 121 formed at resistance 113 for the current signal of the armature winding 106 of controlling described transformer 105, make the envelope of peak value of signal 121 identical with the phase preserving of the AC-input voltage of rectification circuit, and, by described auxiliary winding 107, receive a signal that reflects secondary winding 108 output waveforms; Finally, controlling the ON time of described secondary commutation diode 109 and the ratio of switch periods is a particular expression formula, and exportable constant average current signal 123 is LED load 111 power supplies.
But, under this mode of operation, the voltage signal 122 at output capacitance 110 two ends has very large working frequency ripple wave.Such as: a LED driving power based on the single-stage pfc circuit, output capacitance is 330uF, output current is 300mA, output voltage ripple is 2.5V, 7 LED lamp string pressure drops are 23V, and the LED internal resistance is 16 ohm, and output current ripple is 2.5V/16 ohm=156mA left and right.The cyclic variation meeting of output current ripple causes the variation of LED brightness.Although human eye is difficult for discovering the variation of the brightness of this 100Hz, in this lighting environment, human eye has strong sense of fatigue for a long time.In addition, in the video illumination application places, video pictures brightness has scintillation.
Although can solve above-mentioned defect by increasing output capacitance, can significantly increase the cost of circuit integral body and the volume of power supply.Such as, if output ripple current reduction 90%, the output capacitance capacity will at least increase by 10 times so, the volume of output capacitance also at least increases by 10 times.This in actual applications, the method that adopt to increase the output capacitance capacity is unpractical.
In sum, problem demanding prompt solution is, by without increasing the output capacitance mode, overcoming the above-mentioned defect that has the LED drive scheme now.
Summary of the invention
Technical problem to be solved by this invention is, provides a kind of for reducing the circuit of LED ripple current, and this circuit can overcome the electric current that existing LED drive scheme exports and have the problem that ripple current is larger without increasing output capacitance.
For solving the problems of the technologies described above, the technical solution used in the present invention is: a kind of for reducing the circuit of LED ripple current, this circuit comprises: the first resistance, the first electric capacity, diode, the first operational amplifier, comparator, monostable circuit, switch, the second electric capacity, subtracter and the second operational amplifier, wherein, one end of described the first resistance and the first electric capacity is connected with the anode of external loading, the other end is connected with the P knot of described diode, and the N knot of described diode is connected with the output of described the first operational amplifier; The negative input end of described the first operational amplifier is connected with the P of described diode knot, and positive input terminal is connected with the anode of described external loading, and the output signal of described the first operational amplifier enters described comparator together with threshold signal; The output signal of described comparator is connected with described monostable circuit, the output pulse signal of described monostable circuit is controlled described switch, two other port of described switch is connected with the anode of described external loading and the second input of described subtracter respectively, the first input end of described subtracter is connected with the anode of described external loading, and the output signal of described subtracter enters the positive input terminal of described the second operational amplifier; The output signal of described the second operational amplifier is connected with its negative input end, and the output of described the second operational amplifier is connected with the negative terminal of external loading; One end of described the second electric capacity is connected with the second input of described subtracter, other end ground connection.
Preferably, described for reducing the circuit of LED ripple current, described switch is transistor.
Preferably, describedly for the circuit that reduces the LED ripple current, also comprise: supply module, sampling module, benchmark generation module and feedback module.
Preferably, described for reducing the circuit of LED ripple current, described supply module comprises: the 4th resistance and voltage-stabiliser tube; Described sampling module comprises: the second resistance and the 3rd resistance; Described benchmark generation module comprises: the 5th resistance and the 6th resistance; Described feedback module comprises the 7th resistance and the 8th resistance, and wherein, an end of described the 4th resistance is connected with the anode of described external loading, and the other end is connected with the N knot of described voltage-stabiliser tube, and tie point is signal, the P knot ground connection of described voltage-stabiliser tube; One end of described the second resistance is connected with the anode of described external loading, and the other end is connected with an end of described the 3rd resistance, and tie point is signal, the other end ground connection of described the 3rd resistance; One termination of described the 5th resistance is received described signal, and the other end is connected with an end of described the 6th resistance, and tie point is signal, and described signal enters described comparator together with signal, the other end ground connection of described the 6th resistance; One end of described the 8th resistance is connected with the negative terminal of described external loading, and the other end is connected with described the 7th resistance one end, and tie point is signal, and described signal is connected with the negative input end of described the second operational amplifier, the other end ground connection of described the 7th resistance.
Another embodiment of the present invention is: a kind of for reducing the circuit of LED ripple current, this circuit comprises: the 9th resistance, the 3rd electric capacity, diode, the first operational amplifier, comparator, monostable circuit, switch, the 4th electric capacity, subtracter, the second operational amplifier and transistor, wherein, one end of described the 9th resistance and the 3rd electric capacity is connected with the anode of external loading, the other end is connected with the P knot of described diode, and the N knot of described diode is connected with the output of described the first operational amplifier; The negative input end of described the first operational amplifier is connected with the P of described diode knot, and positive input terminal is connected with the anode of described external loading, and the output signal of described the first operational amplifier enters described comparator together with threshold signal; The output signal of described comparator is connected with described monostable circuit, the output pulse signal of described monostable circuit is controlled described switch, two other port of described switch is connected with the anode of external loading and the second input of described subtracter respectively, the first input end of described subtracter is connected with the anode of described external loading, the output signal of described subtracter enters the negative input end of described the second operational amplifier, and the output signal of described the second operational amplifier is connected with described transistorized grid; Described transistorized drain electrode is connected with the positive input terminal of described the second operational amplifier and the negative terminal of described external loading respectively, described transistorized source ground.
Preferably, described for reducing the circuit of LED ripple current, described transistor is the NMOS pipe.
Preferably, described for reducing the circuit of LED ripple current, described switch is transistor.
Preferably, describedly for the circuit that reduces the LED ripple current, also comprise: supply module, sampling module, benchmark generation module and feedback module.
Advantage of the present invention is, circuit for reducing the LED ripple current involved in the present invention can be done further optimization process to the output of existing LED drive scheme, particularly, this circuit has the output voltage ripple of LED drive scheme now by detection, the voltage of dynamic adjustments LED light source one end, make the voltage equal proportion of this end of LED light source follow the change in voltage of the other end and change, finally realized that LED light source two ends ripple voltage is almost nil, and then made the ripple current of LED light source almost nil.
The accompanying drawing explanation
The circuit diagram that Fig. 1 is the existing LED drive scheme based on the single-stage pfc circuit;
Fig. 2 is the rough schematic view of waveform correlation in circuit shown in Fig. 1;
Fig. 3 is the present invention for the annexation figure between circuit shown in the circuit that reduces the LED ripple current and Fig. 1;
Fig. 4 is the rough schematic view of waveform correlation in circuit shown in Fig. 3;
Fig. 5 is the present invention for the circuit diagram of an embodiment of circuit who reduces the LED ripple current;
Fig. 6 is the rough schematic view of waveform correlation in circuit shown in Fig. 5;
Fig. 7 is the rough schematic view of waveform correlation in circuit shown in Fig. 5;
Fig. 8 is the present invention for the circuit diagram of another embodiment of circuit that reduces the LED ripple current;
Fig. 9 is the circuit diagram after circuit shown in Fig. 5 further improves;
Figure 10 is the circuit diagram after circuit shown in Fig. 8 further improves.
Figure 11 is the rough schematic view of waveform correlation in circuit shown in Fig. 9;
Figure 12 is the rough schematic view of waveform correlation in circuit shown in Fig. 9;
Embodiment
For further disclosing technical scheme of the present invention, hereby be described with reference to the accompanying drawings embodiments of the present invention:
The present invention is as follows for the inventive concept of circuit that reduces the LED ripple current: as shown in Figure 1, the circuit diagram that Fig. 1 is the existing LED drive scheme based on the single-stage pfc circuit, known by aforementioned analysis, circuit shown in Fig. 1 is when work, there is very large working frequency ripple wave at output capacitance 110 two ends, and the cyclic variation meeting of output current ripple causes the variation of LED light source 111 brightness.Based on this, the present invention can be for further processing to the final output current 123 of the existing LED drive scheme based on single-stage PFC framework for the circuit that reduces the LED ripple current, to eliminate described output current 123 working frequency ripple wave electric currents.
The technical scheme that realizes that for the ease of setting forth the present invention the foregoing invention design is taked, now enumerate two exemplary embodiments of the present invention as follows:
The electric circuit constitute, annexation and course of action below in conjunction with one of them embodiment of accompanying drawing explanation the present invention:
Fig. 3 is the present invention for the annexation figure between circuit shown in the circuit that reduces the LED ripple current and Fig. 1, and figure comprises: rectifier bridge 301; Input capacitance 302; Absorbing circuit 304; The transformer 305 formed by armature winding 306, auxiliary winding 307 and secondary winding 308; Secondary commutation diode 309; Output capacitance 310; LED light source 311, i.e. alleged external loading in this specification; Controller circuitry 303; Switching tube 312; Sampling resistor 313.
Fig. 4 is the rough schematic view of waveform correlation in circuit shown in Fig. 3, in the application of above-mentioned Fig. 3, the alternating voltage of input is after described rectifier bridge 301, the voltage signal after rectification 320 of output one-period, the phase place of described voltage signal 320 after rectification is identical with the phase place of input ac voltage; Simultaneously, control chip in this controller circuitry 303 of described controller circuitry 303(can be selected existing chip, such as GL8259, BP3319 etc.) the turning on and off of control switch pipe 312, the voltage signal 321 formed at resistance for the current signal of the armature winding 306 of controlling described transformer 305, make the envelope of peak value of signal 321 identical with the phase preserving of the AC-input voltage of rectification circuit, and, by described auxiliary winding 307, receive a signal that reflects secondary winding 308 output waveforms; Finally, controlling the ON time of described secondary commutation diode 309 and the ratio of switch periods is a particular expression formula, exportable constant average output current signal 323.But, under this mode of operation, output current signal 323 has very large working frequency ripple wave electric current.
Fig. 6 is the rough schematic view of waveform correlation in circuit shown in Fig. 5; Fig. 7 is the rough schematic view of waveform correlation in circuit shown in Fig. 5.Circuit shown in Fig. 5 is in when work, in figure, when signal 511 is greater than signal 322, the first operational amplifier 504 amplifies and makes output signal 512 magnitudes of voltage reduce by error, and signal 512 passes through the magnitude of voltage of diode 503 degrade signals 511; When signal 511 is less than signal 322, the first operational amplifier 504 amplifies and makes output signal 512 magnitudes of voltage raise by error, now, diode 503 meeting disabling signal 511 magnitudes of voltage, finally make, in 322 1 power frequency periods of signal, when signal 322 is greater than signal 511, signal 511 is the control of straight acknowledge(ment) signal 512 not, signal 511 is due to the effect discharged and recharged of the first resistance 501 and the first electric capacity 502, and slightly raise, when signal 511 approach signal 322, signal 511 is followed signal 322 and is changed.
Shown in Fig. 5 in circuit, the output signal 512 of operational amplifier 504 enters comparator 505, output signal 513 together with threshold signal Vref.When signal 512 is greater than threshold signal Vref, signal 513 is high level; When signal 512 is less than threshold signal Vref, signal 513 is low level.
Shown in Fig. 5 in circuit, signal 511 is connected with monostable circuit 506, monostable circuit 506 output pulse signals 514, pulse signal 514 is controlled the conducting of the first switch 507 and closes, and the minimum voltage signal 515 of signal 322 is stored on the second electric capacity 508.
Shown in Fig. 5 in circuit, signal 515 enters subtracter 509 together with signal 322, after two signal subtractions, output signal 516, output signal 516 is exactly the ripple voltage signal of signal 322, output signal 516 enters the positive input terminal of the second operational amplifier 510, the second operational amplifier 510 output signals 324 are connected with the negative input end of the second operational amplifier 510, form and penetrate with amplifier, signal 324 same-phases are followed 516 variation with amplitude, signal 324 is connected with the negative terminal of LED light source 311.
Fig. 9 is the circuit diagram after circuit shown in Fig. 5 further improves, and the circuit in Fig. 9 has increased on the basis of circuit shown in Fig. 5: supply module 531, and described supply module 531 comprises: the 4th resistance 523 and voltage-stabiliser tube 524; Sampling module 532, described sampling module 532 comprises: the second resistance 521 and the 3rd resistance 522; Benchmark generation module 533, described benchmark generation module 533 comprises the 5th resistance 525 and the 6th resistance 526; And feedback module 534, described feedback module 534 comprises the 7th resistance 527 and the 8th resistance 528.
In described supply module 531, described the 4th resistance 523 1 ends are as the input of described supply module 531, the N knot of the other end and described voltage-stabiliser tube 524 is connected, and tie point is signal 541 and this tie point output as described supply module 531, the P knot ground connection of described voltage-stabiliser tube 524;
In described sampling module 532, one end of described the second resistance 521 is as the input of described sampling module 532, the other end is connected with an end of described the 3rd resistance 522, tie point is signal 542 and this tie point output as described sampling module 532, the other end ground connection of described the 3rd resistance 522.
In described benchmark generation module 533, the input that one end of described the 5th resistance 525 is benchmark generation module 533 receives described signal 541, the other end is connected with an end of described the 6th resistance 526, tie point is signal 543 and this tie point output as described benchmark generation module 533, the other end ground connection of described the 6th resistance 526.
In described feedback module 534, one end of described the 8th resistance 528 is as the input of feedback module 534, the other end is described to be connected with the 7th resistance 527 1 ends, and tie point is signal 544 and this tie point output as described feedback module 534, the other end ground connection of described the 7th resistance 527.
The input of described supply module 531 is connected with the anode of described external loading, and the input of described benchmark generation module 533 is connected with the output of described supply module 531, and described benchmark generation module 533 outputs are connected with described comparator 505 negative input ends.Described sampling module 532 inputs are connected with the anode of external loading.One end of described the first resistance 501 and the first electric capacity 502 is connected with the output of described sampling module 532, and the other end is connected with the P knot of described diode 503, and the N knot of described diode 503 is connected with the output of described the first operational amplifier 504; The negative input end of described the first operational amplifier 504 is connected with the P knot of described diode 503, and positive input terminal is connected with the output of described sampling module 532, and the output signal 512 of described the first operational amplifier 504 is connected with described comparator 505 positive input terminals; The output signal 513 of described comparator 505 is connected with described monostable circuit 506, the output pulse signal 514 of described monostable circuit 506 is controlled described the first switch 507, two other port of described the first switch 507 is connected with the output end signal 542 of sampling module 532 and the second input of described subtracter 509 respectively, the first input end of described subtracter 509 is connected with the output of described sampling module 532, and the output signal 516 of described subtracter 509 enters the positive input terminal of described the second operational amplifier 510; The output signal 324 of described the second operational amplifier 510 is connected with the input of described feedback module 534, the negative input end of described the second operational amplifier 510 is connected with the described signal 544 of the output of described feedback module 534, and the output of described the second operational amplifier 510 is connected with the negative terminal of described external loading; One end of described the second electric capacity 508 is connected with the second input of described subtracter 509, other end ground connection.
Figure 11 is the rough schematic view of waveform correlation in circuit shown in Fig. 9; Figure 12 is the rough schematic view of waveform correlation in circuit shown in Fig. 9.Circuit shown in Fig. 9 is when work, in figure, signal 322 is through the dividing potential drop effect of described sampling module 532, described signal 542 becomes 1/K times (the concrete numerical value of K is determined by circuit parameter) of signal 322, when signal 511 is greater than described signal 542, described the first operational amplifier 504 amplifies and makes output signal 512 magnitudes of voltage reduce by error, and signal 512 is by the magnitude of voltage of diode 503 degrade signals 511; When signal 511 is less than signal 542, the first operational amplifier 504 amplifies and makes output signal 512 magnitudes of voltage raise by error, now, diode 503 meeting disabling signal 511 magnitudes of voltage, finally make, in 542 1 power frequency periods of signal, when signal 542 is greater than signal 511, signal 511 is the control of straight acknowledge(ment) signal 512 not, signal 511 is due to the effect discharged and recharged of the first resistance 501 and the first electric capacity 502, and slightly raise, when signal 511 approach signal 542, signal 511 is followed signal 542 and is changed.
Shown in Fig. 9 in circuit, the output signal 512 of operational amplifier 504 enters comparator 505, output signal 513 together with threshold signal 543.When signal 512 is greater than signal 543, signal 513 is high level; When signal 512 is less than signal 543, signal 513 is low level.
Shown in Fig. 9 in circuit, signal 513 input monostable circuits 506, monostable circuit 506 output pulse signals 514, pulse signal 514 is controlled the conducting of the first switch 507 and closes, and the minimum voltage signal 515 of signal 542 is stored on the second electric capacity 508.
Shown in Fig. 9 in circuit, signal 515 enters output signal 516 after subtracter 509, two signal subtractions together with signal 542, and output signal 516 is exactly the ripple voltage signal of signal 542, and the 1/K that its ripple voltage value is signal 322 doubly.Output signal 516 enters the positive input terminal of the second operational amplifier 510, the output signal 324 of the second operational amplifier 510 is connected with the input of feedback module 534, the negative input end of the second operational amplifier 510 is connected with the output of feedback module 534, form the forward proportional amplifier, multiplication factor is K, the K that the magnitude of voltage of signal 324 is signal 516 so doubly, equals the ripple voltage of signal 322.
The electric circuit constitute, annexation and course of action below in conjunction with accompanying drawing explanation another embodiment of the present invention:
Fig. 8 is the present invention for the circuit diagram of another embodiment of circuit that reduces the LED ripple current, circuit in figure comprises: the 9th resistance 801, the 3rd electric capacity 802, diode 803, the first operational amplifier 804, comparator 805, monostable circuit 806, second switch 807, the 4th electric capacity 808, subtracter 809, the second operational amplifier 810, and metal-oxide-semiconductor 820, wherein, one end of described the 9th resistance 801 and the 3rd electric capacity 802 is connected with the anode of external loading, the other end is connected with the P knot of described diode 803, the N knot of described diode 803 is connected with the output of described the first operational amplifier 804, the negative input end of described the first operational amplifier 804 is connected with the P knot of described diode 803, positive input terminal is connected with the anode of described external loading, and the output signal 812 of described the first operational amplifier 804 enters described comparator 805 together with threshold signal Vref, the output signal 813 of described comparator 805 is connected with described monostable circuit 806, the output pulse signal 814 of described monostable circuit 806 is controlled described second switch 807, two other port of described second switch 807 is connected with the anode of external loading and the second input of described subtracter 809 respectively, the first input end of described subtracter 809 is connected with the anode of described external loading, the output signal 816 of described subtracter 809 enters the negative input end of described the second operational amplifier 810, the output signal 817 of described the second operational amplifier 810 is connected with the grid of described metal-oxide-semiconductor 820, the drain electrode of described metal-oxide-semiconductor 820 is connected with the positive input terminal of described the second operational amplifier 810 and the negative terminal of described external loading respectively, the source ground of described metal-oxide-semiconductor 820.
Circuit shown in Fig. 8 is in when work, in figure, when signal 811 is greater than signal 322, the first operational amplifier 804 amplifies and makes output signal 812 magnitudes of voltage reduce by error, and signal 812 passes through the magnitude of voltage of diode 803 degrade signals 811; When signal 811 is less than signal 322, the first operational amplifier 804 amplifies and makes output signal 812 magnitudes of voltage raise by error, and now, diode 803 can disabling signal 811 magnitudes of voltage.Finally make, in a power frequency period of signal 322, when signal 322 is greater than signal 811, signal 811 is the control of straight acknowledge(ment) signal 812 not, signal 811 is due to the effect discharged and recharged of the 9th resistance 801 and the 3rd electric capacity 802, and slightly raise, when signal 811 approach signal 322, signal 811 is followed signal 322 and is changed.
Shown in Fig. 8 in circuit, the output signal 812 of the first operational amplifier 804 enters comparator 805, output signal 813 together with threshold signal Vref.When signal 811 is less than signal 822, signal 813 is high level; When signal 811 is greater than signal 322, signal 813 is low level.
Shown in Fig. 8 in circuit, signal 811 is connected with monostable circuit 806, monostable circuit 806 output pulse signals 814, pulse signal 814 is controlled second switch 807 conductings and is closed, minimum point at signal 322 is sampled, and the minimum voltage signal 815 of signal 322 is stored on the 4th electric capacity 808.
Shown in Fig. 8 in circuit, signal 815 enters subtracter together with signal 322, and after two signal subtractions, output signal 816, and output signal 816 is exactly the ripple voltage signal of signal 322.Output signal 816 enters the negative input end of the second operational amplifier 810, the second operational amplifier 810 output signals 817 are connected with the grid of metal-oxide-semiconductor 820, metal-oxide-semiconductor 820 drain electrodes are connected with the negative terminal of LED light source 311, tie point is signal 324, signal 324 is connected with the anode of the second operational amplifier 810, form negative feedback, make signal 324 follow the same-phase of signal 816, same changes in amplitude.
Figure 10 is the circuit diagram after circuit shown in Fig. 8 further improves, and the circuit in Figure 10 has increased on the basis of circuit shown in Fig. 8: supply module 831, and described supply module 831 comprises the 12 resistance 823 and voltage-stabiliser tube 824; Sampling module 832, described sampling module 832 comprises the tenth resistance 821 and the 11 resistance 822; Benchmark generation module 833, described benchmark generation module 833 comprises the 13 resistance 825 and the 14 resistance 826; And feedback module 834, described feedback module 834 comprises the 15 resistance 827 and the 16 resistance 828.
In described supply module 831, the input that described the 12 resistance 823 1 ends are described supply module 831, the N knot of the other end and described voltage-stabiliser tube 824 is connected, and tie point is signal 841 and this tie point output as described supply module 831, the P knot ground connection of described voltage-stabiliser tube 824.
In described sampling module 832, the input that one end of described the tenth resistance 821 is described sampling module 832, the other end is connected with an end of described the 11 resistance 822, tie point is signal 842 and this tie point output as described sampling module 832, the other end ground connection of described the 11 resistance 822.
In described benchmark generation module 833, the input that one end of described the 13 resistance 825 is described benchmark generation module 833, the other end is connected with an end of described the 14 resistance 826, tie point is signal 843 and this tie point output as described benchmark generation module 833, the other end ground connection of described the 14 resistance 826.
In described feedback module 834, the input that one end of described the 16 resistance 828 is described feedback module 834, the other end is connected with an end of described the 15 resistance 827, tie point is signal 844 and this tie point output as feedback module 834, the other end ground connection of described the 15 resistance 827.
The input of described supply module 831 is connected with the anode of described external loading, and described benchmark generation module 833 inputs are connected with the output of described supply module 831, and the output of described benchmark generation module 833 is connected with described comparator 805 negative input ends.Described sampling module 832 inputs are connected with the anode of described external loading.One end of described the 9th resistance 801 and the 3rd electric capacity 802 is connected with the output of described sampling module 832, and the other end is connected with the P knot of described diode 803, and the N knot of described diode 803 is connected with the output of described the first operational amplifier 804; The negative input end of described the first operational amplifier 804 is connected with the P knot of described diode 803, and positive input terminal is connected with the output of described sampling module 832, and the output signal 812 of described the first operational amplifier 804 is connected with described comparator 805 positive input terminals; The output signal 813 of described comparator 805 is connected with described monostable circuit 806, the output pulse signal 814 of described monostable circuit 806 is controlled described second switch 807, two other port of described second switch 807 is connected with the output of sampling module 832 and the second input of described subtracter 809 respectively, the first input end of described subtracter 809 is connected with the output of described sampling module 832, and the output signal 816 of described subtracter 809 enters the negative input end of described the second operational amplifier 810; The output signal 817 of described the second operational amplifier 810 is connected with the grid of described metal-oxide-semiconductor 820, described metal-oxide-semiconductor 820 drain electrodes are connected with the negative terminal of LED light source 311, tie point is signal 324, the source ground of described metal-oxide-semiconductor 820, described signal 324 is connected with the input of described feedback module 834, the positive input terminal of the output of described feedback module 834 and the second operational amplifier, form negative feedback, and the same-phase that makes described signal 324 follow signal 816 changes; One end of described the 4th electric capacity 808 is connected with the second input of described subtracter 509, other end ground connection.
Circuit shown in Figure 10 is when work, in figure, signal 322 is through the dividing potential drop effect of described sampling module 832, signal 842 becomes 1/K times of described signal 822, when signal 811 is greater than signal 842, the first operational amplifier 804 amplifies and makes output signal 812 magnitudes of voltage reduce by error, and signal 812 is by the magnitude of voltage of diode 803 degrade signals 811; When signal 811 is less than signal 842, the first operational amplifier 804 amplifies and makes output signal 812 magnitudes of voltage raise by error, now, diode 803 meeting disabling signal 811 magnitudes of voltage, finally make, in 842 1 power frequency periods of signal, when signal 842 is greater than signal 811, signal 811 is the control of straight acknowledge(ment) signal 812 not, signal 811 is due to the effect discharged and recharged of the 9th resistance 801 and the 3rd electric capacity 802, and slightly raise, when signal 811 approach signal 842, signal 811 is followed signal 842 and is changed.
Shown in Figure 10 in circuit, the output signal 812 of operational amplifier 804 enters comparator 805, output signal 813 together with threshold signal 843.When signal 812 is greater than signal 843, signal 813 is high level; When signal 812 is less than signal 843, signal 813 is low level.
Shown in Figure 10 in circuit, signal 813 is connected with monostable circuit 806, monostable circuit 806 output pulse signals 814, pulse signal 814 is controlled the conducting of second switch 807 and closes, minimum point at signal 842 is sampled, and the minimum voltage signal 815 of signal 842 is stored on the 4th electric capacity 808.
Shown in Figure 10 in circuit, signal 815 enters output signal 816 after subtracter 809, two signal subtractions together with signal 842, and output signal 816 is exactly the ripple voltage signal of signal 842, and the 1/K that its ripple voltage value is signal 322 doubly.Output signal 816 enters the negative input end of the second operational amplifier 810, and feedback network 834 is the signal after dividing potential drop 844 signal 324, accesses the positive input terminal of the second operational amplifier 810, and the K that the magnitude of voltage of signal 324 is signal 844 doubly.The second operational amplifier 810, feedback network 834 and metal-oxide-semiconductor 820, the degenerative direct proportion amplifier of common composition, multiplication factor is K, the K that the magnitude of voltage of signal 324 is signal 816 so doubly, equal the ripple voltage of signal 322, make signal 324 follow the same-phase of signal 816, K times of signal 816 voltage amplitude variation.
By the above embodiment of the present invention, the ripple voltage that all can finally make LED light source 311 two ends is zero, and ripple current is zero.
More than, by description of listed embodiment, the basic ideas and basic principles of the present invention have been set forth.But the present invention never is limited to above-mentioned listed execution mode, every equivalent variations of doing based on technical scheme of the present invention, improvement and the deliberately of inferior quality behavior of change, all should belong to protection scope of the present invention.
Claims (9)
1. one kind for reducing the circuit of LED ripple current, it is characterized in that, this circuit comprises: the first resistance (501), the first electric capacity (502), diode (503), the first operational amplifier (504), comparator (505), monostable circuit (506), switch (507), the second electric capacity (508), subtracter (509), and second operational amplifier (510), wherein, one end of described the first resistance (501) and the first electric capacity (502) is connected with the anode of external loading, the other end is connected with the P knot of described diode (503), the N knot of described diode (503) is connected with the output of described the first operational amplifier (504), the negative input end of described the first operational amplifier (504) is connected with the P knot of described diode (503), positive input terminal is connected with the anode of described external loading, and the output signal (512) of described the first operational amplifier (504) enters described comparator (505) together with threshold signal, the output signal (513) of described comparator (505) is connected with described monostable circuit (506), the output pulse signal (514) of described monostable circuit (506) is controlled described switch (507), two other port of described switch (507) is connected with the second input of described subtracter (509) with the anode of described external loading respectively, the first input end of described subtracter (509) is connected with the anode of described external loading, and the output signal (516) of described subtracter (509) enters the positive input terminal of described the second operational amplifier (510), the output signal (324) of described the second operational amplifier (510) is connected with its negative input end, and the output of described the second operational amplifier (510) is connected with the negative terminal of external loading, one end of described the second electric capacity (508) is connected with the second input of described subtracter (509), other end ground connection.
2. according to claim 1ly for reducing the circuit of LED ripple current, it is characterized in that, described switch (507) is transistor.
3. according to claim 1ly for reducing the circuit of LED ripple current, it is characterized in that, this circuit also comprises: supply module (531), sampling module (532), benchmark generation module (533) and feedback module (534).
4. according to claim 3ly for reducing the circuit of LED ripple current, it is characterized in that, described supply module (531) comprising: the 4th resistance (523) and voltage-stabiliser tube (524); Described sampling module (532) comprising: the second resistance (521) and the 3rd resistance (522); Described benchmark generation module (533) comprising: the 5th resistance (525) and the 6th resistance (526); Described feedback module (534) comprises the 7th resistance (527) and the 8th resistance (528), wherein, one end of described the 4th resistance (523) is connected with the anode of described external loading, the other end is connected with the N knot of described voltage-stabiliser tube (524), tie point is signal (541), the P knot ground connection of described voltage-stabiliser tube (524); One end of described the second resistance (521) is connected with the anode of described external loading, and the other end is connected with an end of described the 3rd resistance (522), and tie point is signal (542), the other end ground connection of described the 3rd resistance (522); One termination of described the 5th resistance (525) is received described signal (541), the other end is connected with an end of described the 6th resistance (526), tie point is signal (543), described signal (543) enters described comparator (505), the other end ground connection of described the 6th resistance (526) together with signal (512); One end of described the 8th resistance (528) is connected with the negative terminal of described external loading, the other end is connected with described the 7th resistance (527) one ends, tie point is signal (544), described signal (544) is connected with the negative input end of described the second operational amplifier (510), the other end ground connection of described the 7th resistance (527).
5. one kind for reducing the circuit of LED ripple current, it is characterized in that, this circuit comprises: the 9th resistance (801), the 3rd electric capacity (802), diode (803), the first operational amplifier (804), comparator (805), monostable circuit (806), switch (807), the 4th electric capacity (808), subtracter (809), the second operational amplifier (810), and transistor (820), wherein, one end of described the 9th resistance (801) and the 3rd electric capacity (802) is connected with the anode of external loading, the other end is connected with the P knot of described diode (803), the N knot of described diode (803) is connected with the output of described the first operational amplifier (804), the negative input end of described the first operational amplifier (804) is connected with the P knot of described diode (803), positive input terminal is connected with the anode of described external loading, and the output signal (812) of described the first operational amplifier (804) enters described comparator (805) together with threshold signal, the output signal (813) of described comparator (805) is connected with described monostable circuit (806), the output pulse signal (814) of described monostable circuit (806) is controlled described switch (807), two other port of described switch (807) is connected with the second input of described subtracter (809) with the anode of external loading respectively, the first input end of described subtracter (809) is connected with the anode of described external loading, the output signal (816) of described subtracter (809) enters the negative input end of described the second operational amplifier (810), the output signal (817) of described the second operational amplifier (810) is connected with the grid of described transistor (820), the drain electrode of described transistor (820) is connected with the positive input terminal of described the second operational amplifier (810) and the negative terminal of described external loading respectively, the source ground of described transistor (820).
6. according to claim 5ly for reducing the circuit of LED ripple current, it is characterized in that, described transistor (820) is the NMOS pipe.
7. according to claim 5ly for reducing the circuit of LED ripple current, it is characterized in that, described switch (807) is transistor.
8. according to claim 5ly for reducing the circuit of LED ripple current, it is characterized in that, this circuit also comprises: supply module (831), sampling module (832), benchmark generation module (833) and feedback module (834).
9. according to claim 8ly for reducing the circuit of LED ripple current, it is characterized in that, described supply module (831) comprising: the 12 resistance (823) and voltage-stabiliser tube (824); Described sampling module (832) comprising: the tenth resistance (821) and the 11 resistance (822); Described benchmark generation module (833) comprising: the 13 resistance (825) and the 14 resistance (826); Described feedback module (834) comprises the 15 resistance (827) and the 16 resistance (828), wherein, one end of described the 12 resistance (823) is connected with the anode of described external loading, the other end is connected with the N knot of described voltage-stabiliser tube (824), tie point is signal (841), the P knot ground connection of described voltage-stabiliser tube (824); One end of described the tenth resistance (821) is connected with the anode of described external loading, and the other end is connected with an end of described the 11 resistance (822), and tie point is signal (842), the other end ground connection of described the 11 resistance (822); One termination of described the 13 resistance (825) is received described signal (841), the other end is connected with an end of described the 14 resistance (826), tie point is signal (843), described signal (843) enters described comparator (805), the other end ground connection of described the 14 resistance (826) together with signal (812); One end of described the 16 resistance (828) is connected with the negative terminal of described external loading, the other end is described to be connected with the 15 resistance (827) one ends, tie point is signal (844), described signal (844) is connected with the positive input terminal of described the second operational amplifier (810), the other end ground connection of described the 15 resistance (827).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2013203728187U CN203368837U (en) | 2013-06-27 | 2013-06-27 | Circuit for reducing ripple current of LED |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2013203728187U CN203368837U (en) | 2013-06-27 | 2013-06-27 | Circuit for reducing ripple current of LED |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN203368837U true CN203368837U (en) | 2013-12-25 |
Family
ID=49816545
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2013203728187U Withdrawn - After Issue CN203368837U (en) | 2013-06-27 | 2013-06-27 | Circuit for reducing ripple current of LED |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN203368837U (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103298218A (en) * | 2013-06-27 | 2013-09-11 | 苏州智浦芯联电子科技有限公司 | Circuit used for reducing LED ripple current |
| WO2015196863A1 (en) * | 2014-06-24 | 2015-12-30 | Zhejiang Shenghui Lighting Co., Ltd. | Power circuit and diming control method for led lighting device |
-
2013
- 2013-06-27 CN CN2013203728187U patent/CN203368837U/en not_active Withdrawn - After Issue
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103298218A (en) * | 2013-06-27 | 2013-09-11 | 苏州智浦芯联电子科技有限公司 | Circuit used for reducing LED ripple current |
| CN103298218B (en) * | 2013-06-27 | 2015-04-22 | 苏州智浦芯联电子科技有限公司 | Circuit used for reducing LED ripple current |
| WO2015196863A1 (en) * | 2014-06-24 | 2015-12-30 | Zhejiang Shenghui Lighting Co., Ltd. | Power circuit and diming control method for led lighting device |
| US9826584B2 (en) | 2014-06-24 | 2017-11-21 | Zhejiang Shenghui Lighting Co., Ltd | Power circuit and diming control method for LED lighting device |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN103298218B (en) | Circuit used for reducing LED ripple current | |
| CN103746566B (en) | Primary side controlled switching power supply and control method thereof | |
| CN104836446A (en) | Controlling method for isolated converter, control circuit and switching mode power supply | |
| CN104300773B (en) | Self-adaptation dummy-load circuit | |
| CN103648202A (en) | Active power factor correction control circuit, chip and LED (Light Emitting Diode) drive circuit | |
| CN103716952B (en) | A kind of LED switch power supply and control method thereof | |
| CN203660880U (en) | Two-stage boost topological circuit | |
| CN203368837U (en) | Circuit for reducing ripple current of LED | |
| CN109688669A (en) | A kind of High Power Factor no electrolytic capacitor LED drive power and its control method | |
| CN104753335A (en) | Quadratic form Buck power factor correction converter | |
| CN110831284B (en) | LED driving power supply and controller thereof | |
| CN203206143U (en) | Step-down switching power supply | |
| CN204497972U (en) | A kind of novel retention time circuit structure | |
| CN204578355U (en) | A kind of quadratic form Buck power factor correcting converter | |
| CN103763841B (en) | High Power Factor is without the LED drive circuit of stroboscopic | |
| CN103889121B (en) | A kind of ripple current suppresses circuit | |
| CN203840596U (en) | Ripple current suppression circuit and LED circuit | |
| CN106602861B (en) | Improve the control circuit of Active PFC transfer efficiency | |
| CN204392101U (en) | AC/DC circuit and switching power supply | |
| CN203289692U (en) | LED linear constant current driving controller with wide input voltage range and LED driving device | |
| CN205141991U (en) | PFC (power factor correction) circuit | |
| CN204392107U (en) | Converter circuit and switching power supply | |
| CN106353572B (en) | Output end power loss detection means and switch conversion power-supply system with the device | |
| CN203840592U (en) | A high power factor stroboflash-free non-isolation type LED drive circuit | |
| CN203590035U (en) | High-power factor low-harmonic distortion constant current circuit and device |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| AV01 | Patent right actively abandoned |
Granted publication date: 20131225 Effective date of abandoning: 20150422 |