CN104812121B - Led drive circuit - Google Patents
Led drive circuit Download PDFInfo
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- CN104812121B CN104812121B CN201410039919.1A CN201410039919A CN104812121B CN 104812121 B CN104812121 B CN 104812121B CN 201410039919 A CN201410039919 A CN 201410039919A CN 104812121 B CN104812121 B CN 104812121B
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
- H05B45/30—Driver circuits
- H05B45/37—Converter circuits
- H05B45/3725—Switched mode power supply [SMPS]
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B20/00—Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps
- Y02B20/30—Semiconductor lamps, e.g. solid state lamps [SSL] light emitting diodes [LED] or organic LED [OLED]
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- Circuit Arrangement For Electric Light Sources In General (AREA)
- Dc-Dc Converters (AREA)
Abstract
The present invention relates to a kind of LED drive circuit, including：Switching Power Supply, for receiving external power supply and the output voltage after adjustment being generated according to adjustment signal；Linear power source circuit for receiving the output voltage of the Switching Power Supply, and is converted into linear voltage and is supplied to LED module；Ripple signal sample circuit, for acquiring the ripple signal of linear power source circuit generation；Ripple signal compensation circuit for receiving the collected ripple signal, and is converted into compensation voltage signal；And output voltage regulation circuit, for receiving the voltage feedback signal of the linear power source circuit and the compensation voltage signal, and the adjustment signal is generated according to the difference between the voltage feedback signal and reference voltage and is adjusted come the output voltage to the Switching Power Supply, wherein the reference voltage is equal to the sum of preset first reference voltage source and the compensation voltage signal.
Description
Technical field
The present invention relates to for driving the driving circuit of LED light source.
Background technology
LED is as a kind of novel illumination light source, with its long-life, specular removal, how photochromic and once light-distribution directional illumination work(
Energy can work under safe voltage and wait many advantages, become the development trend of lighting source of new generation.
Traditional LED drive circuit usually passes through Switching Power Supply（Switched-Mode Power Supply,SMPS）It connects
Receive external ac power source input（Or DC supply input）And according to adjustment signal such as pulsewidth modulation（PWM）Signal provides to adjust
To the output voltage signal of LED module, so that it meets the needs of power supply.
Simplest LED drive circuit only includes level-one Switching Power Supply, although this structure is simple in structure, level-one switch electricity
It is not usually highly stable that source, which is supplied to the output voltage of LED module, the electric current in LED module can be influenced, so as to generate line
Wave electric current（Ripple Current）, in turn result in the service life that quality of lighting declines and can reduce LED module.
And more complicated LED drive circuit then includes at least two-stage Switching Power Supply or including dedicated constant current chip, passes through
The adjustment of two-stage and two-stage more than Switching Power Supply or constant current chip can become more stable final output voltage, because two
Grade or two-stage more than Switching Power Supply also can to adjustment more than external power supply progress two-stage or two-stage or dedicated constant current chip
Accurate adjustment is carried out to external power supply.But often increase a Switching Power Supply or often use a dedicated constant current chip, all
The cost and design complexities of LED drive circuit will be significantly increased, suitable for application in common occasion.
It is therefore desirable to a kind of new LED drive circuit is provided to solve the above problems.
Invention content
Basic comprehension of the one or more aspects of the present invention in order to the present invention is concluded now, and the wherein conclusion is not
The extensive overview of the present invention, and certain elements of the mark present invention are not intended to, it is also not intended to mark its range.On the contrary,
The main purpose of the conclusion is that some concepts of the present invention are presented before more detailed description is presented below with reduced form.
The invention reside in a kind of LED drive circuit is provided, for driving LED module.The LED drive circuit includes：
Switching Power Supply, for receiving external power supply and the output voltage after adjustment being generated according to adjustment signal；
Linear power source circuit for receiving the output voltage of the Switching Power Supply, and is converted into linear voltage and is supplied to
The LED module；
Ripple signal sample circuit, for acquiring the ripple signal of linear power source circuit generation；
Ripple signal compensation circuit for receiving the collected ripple signal, and is converted into compensation voltage signal；
And
Output voltage regulation circuit, for receiving the voltage feedback signal of the linear power source circuit and offset voltage letter
Number, and the adjustment signal is generated come the output to the Switching Power Supply according to the difference between the voltage feedback signal and reference voltage
Voltage is adjusted, and wherein the reference voltage is equal to the sum of preset first reference voltage source and the compensation voltage signal.
Compared to the prior art, the output voltage regulation circuit provided in LED drive circuit of the invention makes according to synthesis
Feedback and acquisition signal come to Switching Power Supply carry out comprehensively and be accurately controlled.On the one hand, which connects
The voltage feedback signal from linear power source circuit is received, the defeated of the Switching Power Supply can be monitored in real time by the voltage feedback signal
Go out voltage and meet desired value, i.e., be compared with the first reference voltage source, be then based on comparison result and generate corresponding adjustment letter
Number adjust the output voltage of the Switching Power Supply；On the other hand, which is also further believed by the ripple
Ripple signal of number sample circuit acquisition from linear power source circuit, and pass through the ripple signal compensation circuit and obtain the sampling
The signal energy being in ripple signal in the period with ripple current, and the compensation voltage signal is translated into, make
It is compared after being combined with first reference voltage source with the voltage feedback signal from linear power source circuit, so
Make the adjustment signal of generation the Switching Power Supply not only be made to meet desired value, and the LED module can be made normal under lowest power
Work, thereby reduces the loss of power.In addition, since the LED drive circuit of the present invention only applies level-one Switching Power Supply, and
Not using two level or multi-stage switching power supply or dedicated constant current chip, therefore cost has been greatly reduced it.
Description of the drawings
Embodiments of the present invention are described in conjunction with the accompanying drawings, the present invention may be better understood, in attached drawing
In：
Fig. 1 is a kind of schematic block diagram of better embodiment of LED drive circuit of the present invention.
Fig. 2 illustrates a kind of circuit diagram for preferably applying mode of the current rectifying and wave filtering circuit and linear power source circuit in Fig. 1.
Fig. 3 illustrates a kind of circuit diagram for preferably applying mode of the output voltage regulation circuit in Fig. 1.
Fig. 4 illustrates a kind of circuit diagram for preferably applying mode of the ripple signal sample circuit in Fig. 1.
Fig. 5 illustrates the relational graph between ripple current, ripple voltage and shaping voltage.
Fig. 6 illustrates a kind of circuit diagram for preferably applying mode of the ripple voltage Shaping Module in Fig. 4.
Fig. 7 illustrates a kind of circuit diagram for preferably applying mode of the ripple signal compensation circuit in Fig. 1.
Specific embodiment
The specific embodiment of the present invention explained below, it should be pointed out that in the specific descriptions of these embodiments
In the process, in order to carry out brief and concise description, this specification can not possibly make in detail all features of practical embodiment
Most description.It is to be understood that during the actual implementation of any one embodiment, as in any one work
During journey project or design object, in order to realize the objectives of developer, in order to meet, system is relevant or quotient
The relevant limitation of industry can usually make various specific decisions, and this can also be implemented from a kind of embodiment to another kind
It changes between mode.Moreover, it is to be understood that although effort made in this development process may be complicated
And it is interminable, however for for the relevant those of ordinary skill in the art of present disclosure, in the disclosure
Some designs carried out on the basis of the technology contents of exposure, the changes such as manufacture or production are conventional technology, no
It should be understood to that content of this disclosure is insufficient.
Unless otherwise defined, the technical term or scientific terminology used in claims and specification should be this hair
The ordinary meaning that the personage with general technical ability is understood in bright technical field.Present patent application specification and power
" first ", " second " and the similar word used in sharp claim is not offered as any sequence, quantity or importance, and
It is used only to distinguish different component parts.The similar word such as "one" or " one " is not offered as quantity limitation, but represents
There are at least one.Either the similar word such as "comprising" means to appear in the element before " comprising " or "comprising" " comprising "
Either object covers the element for appearing in " comprising " or "comprising" presented hereinafter or object and its equivalent element, it is not excluded that
Other elements or object." connection " either the similar word such as " connected " is not limited to physics or mechanical connection,
But electrical connection can be included, it is either directly or indirect.
It please refers to Fig.1, is a kind of schematic block diagram of better embodiment of LED drive circuit 100 of the present invention.The LED drives
Dynamic circuit 100 includes external power supply input interface 110, current rectifying and wave filtering circuit 120, Switching Power Supply（Switched-Mode Power
Supply,SMPS）130th, linear power source circuit 140, LED module 150, output voltage regulation circuit 160, ripple signal sampling electricity
Road 170 and ripple signal compensation circuit 180.Wherein, which can be the component part of the LED drive circuit 100,
Or respective independent part, here the LED drive circuit part is incorporated merely to illustrating to facilitate.
The external power supply input interface 110 is used to receive external power supply signal（It is not shown）, such as 220V AC powers or 24V
DC power supply etc..Here it is merely illustrative of, actually external power supply signal can be adjusted as needed, the external power supply
It is provided after a series of controls that signal passes through 100 subsequent conditioning circuit of LED drive circuit and stablizes suitable output voltage and give its inside
LED module 150.The LED module 150 may include single LED element, it is also possible to it is combined including several LED elements, and
The type of LED element is also not necessarily limited to a certain kind, can be adjusted according to actual needs.
The current rectifying and wave filtering circuit 120 is used to carry out rectification and/or filtering process to external power supply, to obtain Switching Power Supply
130 required input voltages.Since current rectifying and wave filtering circuit is more ripe technology, therefore to only give Fig. 2 schematic by the present invention
Rectification embodiment be illustrated as an example.According to actual needs, the position of the current rectifying and wave filtering circuit 120 also can be into
The corresponding adjustment of row, such as other than the example of Fig. 1 signals, which can also be arranged on the Switching Power Supply
130 rear end, to carry out rectification and/or filtering process to the output voltage signal of Switching Power Supply 130.Or by the rectification
The rectifying part of filter circuit 120 is set to the front end of the Switching Power Supply 130, and the filtering part of the current rectifying and wave filtering circuit 120
Then it is set to the rear end of the Switching Power Supply 130.Again alternatively, the filtering part of the current rectifying and wave filtering circuit 120 is set to the switch
The front end of power supply 130, and the rectifying part of the current rectifying and wave filtering circuit 120 is then set to the rear end of the Switching Power Supply 130.Above-mentioned act
Some embodiments of example, specifically can also carry out other kinds of adjustment, be not limited to the above-mentioned example provided according to actual needs
Son.Other than arrangement or filtering process, it is suitable that other can be also carried out to the signal in circuit according to the needs of actual circuit
Processing, such as enhanced processing etc. due to these signal processings and the designing points of non-present invention, therefore do not illustrate here, and
It does not illustrate in figure yet, but according to the understanding of those skilled in the art, corresponding signal processing can be made.
The Switching Power Supply 130 arranges filtered external power supply signal for receiving the external power supply signal or passing through, and
Its output voltage 132 is adjusted according to the adjustment signal 162 from output voltage regulation circuit 160, for example, the adjustment signal 162
It can be the direct current signal that an amplitude changes up and down with feedback signal.It is appreciated that as an example, the switch
PWM adjustment signal control integrated circuits and the transistor as switch element are generally included inside power supply 130（It is not shown）, should
PWM adjustment signal control integrated circuits generate the pwm signal of duty ratio corresponding according to the adjustment signal 162, and then this is controlled to open
The break-make of element is closed, so as to the corresponding output voltage 132 for adjusting the Switching Power Supply 130.PWM adjustment signal control integrated circuits
It is usually connect by external interface with the output voltage regulation circuit 160, such as optical coupling input interface.The output voltage regulation circuit
160 input the adjustment signal 162 by above-mentioned external interface adjusts signal control integrated circuit to the PWM.Due to the switch
Concrete structure inside power supply 130 is not the invention main points of the present invention, therefore does not elaborate here.
The linear power supply（Linear Source）Circuit 140 is used to receive the output voltage 132 of the Switching Power Supply 130 simultaneously
It is converted to stable linear voltage 142 and is supplied to the LED module 150, so that it is worked normally.Due to the linear power source circuit
140 be more ripe technology, therefore the present invention only provides the schematical linear power supply embodiment of Fig. 2 and said as an example
It is bright, other kinds of linear power source circuit also can be selected in other embodiment or linear power supply chip is realized and provides regulated linear
The function of voltage is not limited to the embodiment that Fig. 2 is provided, will not enumerate here.
The output voltage regulation circuit 160 is used to receive the voltage feedback signal 144 of the linear power source circuit 140, the electricity
Press feedback signal 144 indirectly（Or directly）Reflect the variation of the output voltage 132 of the Switching Power Supply 130, this variation
Caused by may be the reasons such as variation or Switching Power Supply 130 itself as external power supply.When the output electricity of the Switching Power Supply 130
When pressure 132 changes, which, which exports to the linear voltage 142 of LED module 150, also to change therewith,
There is spread of voltage situation, this may result in the unstable of the work of LED module 150.For this purpose, the output voltage adjusts electricity
Road 160 is according to the voltage feedback signal 144 received and preset reference voltage（Reference voltage source as shown in Figure 3
Vref1）Comparison result generate corresponding adjustment signal（That is PWM adjusts signal 162）The Switching Power Supply 130 is given to, it should with control
PWM adjustment signal control integrated circuits in Switching Power Supply 130, PWM adjustment signal control integrated circuits are believed according to the adjustment
The duty ratio of numbers 162 adjustment PWM adjustment signals, and then output voltage 132 is adjusted, so that the linear power source circuit 140 output
Linear voltage 142 is adjusted in the range of meeting the requirements, so as to ensure that the LED module 150 can work normally.Subsequent paragraph will
A specific better embodiment of the output voltage regulation circuit 160 is provided with reference to Fig. 3, its specific work is described in detail
Make principle.
But the reference voltage referred in above-mentioned output voltage regulation circuit 160 is changeless, therefore only root sometimes
Output voltage 132 cannot be adjusted completely according to the preset reference voltage reaches satisfactory optimum range.For example, in order to effective
Eliminate and flow through the ripple of electric current in LED module 150, need the pressure drop by linear power supply in linear power source circuit 140 be set with compared with
Big surplus, to cope with the error of the energy fluctuation of external power input or output voltage 132.Therefore, it is only default by this
Reference voltage Vref1Output voltage 132 after adjustment may make electric energy loss become higher, because not to linear power supply
The ripple signal that circuit 140 generates compensates.Therefore LED drive circuit 100 of the present invention further additionally provides ripple signal adopts
Sample circuit 170 and ripple signal compensation circuit 180.
The ripple signal sample circuit 170 is used to carry out it when the linear power source circuit 142 generates ripple signal 146
Real-time sampling, the ripple signal 173 after the sampling, which exports, gives the ripple signal compensation circuit 180.The ripple signal compensation circuit
Ripple signal after 180 pairs of samplings（Or the ripple signal after shaping）Control is compensated, and exports compensation voltage signal 182
It is given to the output voltage regulation circuit 160.The output voltage regulation circuit 160 is according to the preset reference voltage in it and the compensation
Voltage signal 182 is corresponding again after combining to generate adjustment signal 162, and the adjustment signal 162 after combination adjustment will make the linear electricity
The power that the linear voltage 142 that source circuit 140 exports is adjusted in the range of meeting the requirements and consumed is minimum.Subsequent paragraph will be tied
The specific better embodiment that Fig. 4-Fig. 7 provides the ripple signal sample circuit 170 and ripple signal compensation circuit 180 is closed,
Its specific operation principle is described in detail.
Above-mentioned paragraph teaches the whole operation principle of LED drive circuit of the present invention 100, below in conjunction with Fig. 2-Fig. 7 and
Specific embodiment introduces the exemplary circuit structure of various pieces and operation principle respectively.It should be noted that these embodiment party
Formula is just for the sake of facilitating the operation principle for illustrating respective circuit and some embodiments enumerated, and these embodiments can be with
According to the adjusted design of the knowledge of persons skilled in the art progress routinely, it is not limited to example given here.
It please refers to Fig.2, illustrates one kind of current rectifying and wave filtering circuit 120 and linear power source circuit 140 in Fig. 1 and preferably apply mode
Circuit diagram.As the foregoing description, Fig. 2 simply shows a schematical embodiment, in other embodiment, the rectification
Filter circuit 120 and linear power source circuit 140 can need to be designed to other circuit structures according to different.
In the embodiment of Fig. 2, which includes a bridge being made of four diode D1-D4
Formula rectification circuit, the i.e. anode of diode D1 and the cathode of diode D3 are connected to the external power supply input interface 110
One leading-out terminal, the anode of diode D2 are connected to the external power supply input interface 110 with the cathode of diode D4
Another leading-out terminal, the cathode of diode D1 and the anode of diode D3 be connected to the Switching Power Supply 130 one are defeated
Enter terminal, the cathode of diode D2 is connected to another input terminal of the Switching Power Supply 130 with the anode of diode D4.
Since the bridge rectifier is existing common technique, therefore its operation principle is no longer described in detail here.It, should in present embodiment
Do not include filter circuit part in current rectifying and wave filtering circuit 120, this is because in some applications, need can be met without filtering
It will.In other embodiments, suitable filter circuit, such as capacitor filter can be accordingly increased as needed.Due to filter
Wave circuit is also existing common technique, therefore here to simplify the explanation, do not provide corresponding example and diagram.
In the embodiment of Fig. 2, which includes a controllable accurate source of stable pressure device TL1（Such as type
Number be TL431）, three resistance R1-R3, a filter capacitor C1An and electronic switch（Such as metal-oxide-semiconductor）Q1。
Two voltage output ends of the Switching Power Supply 130 and two resistance R1And R2Series connection, with to the Switching Power Supply 130
Output voltage carries out voltage division processing.Resistance R2Both ends respectively with controllable accurate source of stable pressure device TL1Cathode and anode connect
It connects, resistance R2The voltage distribution at both ends meets controllable accurate source of stable pressure device TL1Cathode and the voltage request at anode both ends,
It is set with specific reference to actual parameter.Capacitance C1With electronic switch Q1And resistance R3Form series circuit after with the electricity
Hinder R1And R2The series circuit of composition is connected in parallel.Electronic switch Q1Control terminal be connected to resistance R1With R2Between section
On point D, controllable accurate source of stable pressure device TL1Reference pole be connected to electronic switch Q1With resistance R3Between node C
On.Capacitance C1Two-end-point A and B be respectively connected to two power inputs of the LED module 150.
During work, which provides output voltage VA(i.e. the 132 of Fig. 1 signals) are given to linear power supply electricity
Road 140, such as 24V DC voltages.According to controllable accurate source of stable pressure device TL1Device function, with reference to pole by export fix
Voltage be given on node C so that the voltage clamping on node C is such as clamped to 1.25V in the fixed voltage.When C points
Voltage VC>During 1.25V, due to electronic switch Q1It is operated in amplification region, the voltage V of D pointsDIt can decline, and then between B points and C points
Voltage VBCIt can rise.Due to VC=VA-VAB-VBC, therefore VBCAfter rising, the voltage V of C pointsCCan decline until the clamp voltage such as
1.25V.By a series of above-mentioned controls, capacitance C1Both ends will export linear voltage VAB（That is the 142 of Fig. 1 signals）It is given to this
LED module 150.In other embodiment, it also can provide linear voltage by the linear power source circuit of other circuit structures and be given to
The LED module 150, is selected with specific reference to actual design requirement, is no longer illustrated one by one here.
Meanwhile in present embodiment, the voltage V of the B pointsBIt is exported as the voltage feedback signal 144 and gives the output voltage
Adjust circuit 160.Why the voltage feedback signal 144 can as reflect the Switching Power Supply 130 output voltage VA, be by
In VB=VA-VAB, therefore VBReflect the output voltage V of the Switching Power Supply 130 indirectlyA.In other embodiment, can also directly by
The output voltage V of the Switching Power SupplyAIt exports to the output voltage regulation circuit 160 or incites somebody to action as the voltage feedback signal 144
Other associated voltage signals are not limited to a certain feedback system as the voltage feedback signal 144.
Please continue to refer to Fig. 3, a kind of circuit for preferably applying mode of the output voltage regulation circuit 160 in Fig. 1 is illustrated
Figure.In present embodiment, which includes a comparator U1, a reference voltage source Vref1And one
Capacitance C2。
Comparator U1Inverting input receive the linear power source circuit 140 output the voltage feedback signal 144, should
Comparator U1Normal phase input end receive reference voltage source Vref1, capacitance C2It is connected to comparator U1Inverting input
Between output terminal, comparator U1Output terminal generate the adjustment signal 162.Reference voltage source Vref1According to switch electricity
Source 130 is actually needed the output voltage generated and sets, i.e. reference voltage source Vref1Value correspond to the Switching Power Supply 130 and it is expected
The output voltage of generation directly corresponds to the desired value of the voltage feedback signal 144.
During work, when the voltage feedback signal 144 is less than reference voltage source Vref1When, show that the Switching Power Supply 130 is produced
Raw output voltage 132 is smaller than desired value, so when the adjustment signal 162 adjustment signal 162 that will export a positive value
Improve Switching Power Supply 130 in PWM adjustment signal duty ratio, and then improve the Switching Power Supply 130 output voltage 132 so that its
It is equal to or levels off to desired value.Conversely, when the voltage feedback signal 144 is more than reference voltage source Vref1When, show the switch
The output voltage 132 that power supply 130 generates is bigger than desired value, so when the adjustment signal 162 adjustment that will export a negative value
Signal 162 adjusts the duty ratio of signal to reduce PWM in Switching Power Supply 130, and then reduces the output voltage of the Switching Power Supply 130
132 to make it equal to or level off to desired value.Therefore, by the feedback adjustment of the output voltage regulation circuit 160, this can be opened
The output voltage 132 that powered-down source 130 generates is consistently equal to or levels off to desired value.In other embodiments, the output voltage
The circuit form of other structures can also be designed to, such as by realizing the Voltage Feedback using comparable chip by adjusting circuit 160
Signal 144 and reference voltage source Vref1Comparison, and export corresponding adjustment signal 162, differ an illustration here.
Please continue to refer to Fig. 4, a kind of circuit for preferably applying mode of the ripple signal sample circuit 170 in Fig. 1 is illustrated
Figure.In present embodiment, which includes ripple voltage Shaping Module 172 and shaping voltage output mould
Block 174.In some embodiments, shaping voltage output mould also can be only omitted using the ripple voltage Shaping Module 172
Block 174.
In this embodiment, which is the voltage V according to B points in Fig. 2BAs the ripple
What the sampling source of signal 146 was sampled, i.e., sampling source and the above-mentioned voltage feedback signal 144 of the ripple signal 146 is anti-
Feed is same signal source.In other embodiments, other different sampled points also can be selected and sampled or feedback capture,
As long as meet feedback sources or sample feedback signal or the direct or indirect phase of sampled signal that the signal at source is obtained with actual needs
Association is not limited to a certain feedback or sample mode.
For the ripple voltage Shaping Module 172 in present embodiment, including a comparator U2An and reference electricity
Potential source Vref2.In this embodiment, which is used to the ripple signal 146 being converted into square wave letter
Number, in order to which subsequently to the processing of signal, other embodiment also translates to other kinds of signal or turns without shaping
It changes.
In this embodiment, comparator U2Inverting input for receiving the ripple signal 146, comparator U2
Normal phase input end for receiving reference voltage source Vref2.With reference to figure 5, ripple current 52, ripple voltage 54 and whole are illustrated
Relational graph between shape voltage 56.Wherein, which is to flow through the current signal of the LED module 150 in generation ripple
Partial waveform figure during electric current, it can be seen that in period T1-T2, T3-T4, T5-T6 ripple-free electric current generate, and when
Between section T2-T3, T4-T5, T6-T7 when produce ripple current.Since direct sampled current signals 52 might have energy loss
The problem of, therefore what present embodiment directly sampled is ripple voltage signal 54 associated there（I.e. in linear power source circuit 140
B points at voltage signal VB）.From figure 5 it can be seen that the period T1-T2, T3-T4, T5-T6 that are generated in ripple-free electric current
Interior, the amplitude of the ripple voltage 54 is positive value, and in the period T2-T3 for generating ripple current, T4-T5, T6-T7, it should
The amplitude of ripple voltage 54 is equal to zero.Therefore, pass through comparator U2Shaping, can be by the amplitude of the ripple voltage 54 just
The period equal shaping of value is equal to zero, and the equal shaping of the amplitude of the ripple voltage 54 null period is equal to one and fixes electricity
Pressure value, i.e., such as the square-wave signal of shaping voltage 56（The 1731 of corresponding diagram 4）.Therefore, compare ripple current 52 and shaping voltage 56,
Understand that the period T2-T3 of ripple occurs in the ripple current 52, T4-T5, T6-T7 correspond to the amplitude time of the shaping voltage 56
Section, and do not occur the period T1-T2 of ripple, T3-T4, T5-T6 correspond to the low amplitude value period of the shaping voltage 56.
In other embodiments, which can also be realized by other kinds of shaping circuit.
Such as the another embodiment of Fig. 6 signals.In the embodiment, which includes resistance R6And electricity
Sub switch Q4(such as triode).Resistance R6With electronic switch Q4It is series at a voltage source VccAnd between ground, the electronic switch
Q4Control terminal for receiving the ripple signal 146, resistance R6With electronic switch Q4Node be used for as shaping voltage 1731
（Similar to 56 in Fig. 5）Output.It is apparent from, when the ripple signal 146（Similar to 54 in Fig. 5）During for positive value, the electronics
Switch Q4Conducting, therefore the shaping voltage 1731 is equal to zero, when the ripple signal 146 is zero, electronic switch Q4Cut-off, therefore should
Shaping voltage 1731 is equal to a fixed voltage value.The ripple voltage Shaping Module 172 can also be realized by other circuits, here not
It illustrates one by one.
Fig. 4 is back to, which further comprises a shaping voltage output module 174, at this
In embodiment, which is an image current source circuit, typically comprises two resistance R4And
R5, triode Q2And Q3, resistance R4With triode Q2Form the side of image current source circuit, resistance R5With Q3Form image current
The opposite side of source circuit by the output function of the image current source circuit 174, can produce the ripple voltage Shaping Module 172
Exporting for stablizing again after the high-amplitude value part generation image current 1732 of raw shaping square-wave voltage 1731 is mended to the ripple signal
Repay circuit 180.Since image current source circuit is existing circuit common, therefore do not illustrate here.As described above, at it
In his embodiment, 174 part of shaping voltage output module can be also omitted, and directly by the ripple voltage Shaping Module 172
The shaping voltage 1731 of generation, which exports, gives the ripple signal compensation circuit 180.In other embodiment, shaping voltage output mould
What block 174 can also be designed to other kinds of voltage follower circuit to stablize obtains the 1731 high-amplitude value part of shaping voltage
Voltage output.
Please continue to refer to Fig. 7, a kind of circuit for preferably applying mode of the ripple signal compensation circuit 180 in Fig. 1 is illustrated
Figure.In this embodiment, which includes resistance R7, resistance R8, diode D5And storage capacitor C3。
Diode D5Anode pass through resistance R7The ripple signal sample circuit 170 is connected to, to receive adopting for its generation
Ripple signal 173 after sample（Signal 1731 or 1732 as shown in Figure 4）.Diode D5Cathode connect storage capacitor C3
After be grounded.Diode D5With storage capacitor C3Between node pass through resistance R8It is connected to the output voltage regulation circuit
160, to provide it the voltage signal V of compensationadd(182 in collective reference Fig. 3, i.e. Fig. 1).The ripple signal compensation circuit
Resistance R in 1807、R8And diode D5It is for adjusting the performance of accumulator, if resistance plays the role of current limliting, two
Pole pipe plays the role of preventing current reflux.In other embodiment, storage capacitor C3It can be by other with energy-storage function
Energy-storage travelling wave tube replace, and resistance R7、R8And diode D5It can be replaced by the electronic component of other similar functions, electricity
Line structure can be also adjusted as needed, be not limited to the example that present embodiment provides.
During work, when linear power source circuit 140 generates ripple current, such as period T2-T3, T4- shown in fig. 5
T5, T6-T7, the ripple signal sample circuit 170 generate reshaping signal 173, square-wave signal 56 as shown in Figure 5 by corresponding.It is right
Ying Di, in the positive period T2-T3 of the square-wave signal 56, T4-T5, T6-T7, which will be right
Storage capacitor C in the ripple signal compensation circuit 1803It charges, increases its both end voltage.And then the increased voltage
VddThe comparator U in output voltage regulation circuit 160 shown in Fig. 3 will be compensated1The voltage reference value V of normal phase input endref1,
The reference voltage being compared with the feedback voltage signal of the linear power source circuit 140 142 can so be improved（Buffer voltagc）'s
Range, effectively to eliminate the ripple current in the linear power source circuit 140.In addition, again due to the ripple signal compensation circuit
Storage capacitor C in 1803Electric energy increment correspond to ripple current in the linear power source circuit 140, therefore the increased voltage
VaddThe ripple current in linear power source circuit 140 can just be eliminated, you can make the LED module 150 normal under lowest power
Work, thus reduce the loss of power.In this way, by the control of foregoing circuit, LED drive circuit 100 of the present invention can be most
LED module 150 is normally controlled to work under low-power.In addition, since the LED drive circuit 100 of the present invention only applies one
Grade Switching Power Supply, and not using two level or multi-stage switching power supply or dedicated constant current chip, therefore it has been greatly reduced cost.
Although with reference to specific embodiment, the present invention is described, it will be appreciated by those skilled in the art that
It can be with many modifications may be made and modification to the present invention.It is therefore contemplated that claims be intended to be covered in the present invention
All such modifications and modification in true spirit and range.
Claims (10)
1. a kind of LED drive circuit, for driving LED module, it is characterised in that：The LED drive circuit includes：
Switching Power Supply, for receiving external power supply and the output voltage after adjustment being generated according to adjustment signal；
Linear power source circuit for receiving the output voltage of the Switching Power Supply, and is converted into linear voltage and is supplied to the LED
Module；
Ripple signal sample circuit, for acquiring the ripple signal of linear power source circuit generation；
Ripple signal compensation circuit for receiving the collected ripple signal, and is converted into compensation voltage signal；And
Output voltage regulation circuit, for receiving the voltage feedback signal of the linear power source circuit and the compensation voltage signal, and
The adjustment signal is generated come the output voltage to the Switching Power Supply according to the difference between the voltage feedback signal and reference voltage
It is adjusted, wherein the reference voltage is equal to the sum of preset first reference voltage source and the compensation voltage signal.
2. the ripple signal of LED drive circuit as described in claim 1, wherein the ripple signal sample circuit acquisition is and line
The corresponding ripple voltage signal of wave electric current.
3. LED drive circuit as claimed in claim 2, wherein the ripple signal sample circuit include a comparator and one
Preset second reference voltage source, the inverting input of the comparator receive the ripple voltage signal, and the positive of the comparator is defeated
Enter to hold and receive second reference voltage source, the ripple signal after the output terminal output Shaping of the comparator, the ripple after the shaping
There is the period of ripple current for the high-amplitude value part of square-wave signal and square-wave signal correspondence in signal.
4. LED drive circuit as claimed in claim 2, wherein the ripple signal sample circuit include a resistance and one is opened
Element is closed, the resistance and the switch element are connected on one between voltage source and ground, and the control terminal of the switch element receives the line
Wave voltage signal, the ripple signal after node output Shaping between the resistance and the switch element, the ripple letter after the shaping
Number there is the period of ripple current for the high-amplitude value part correspondence of square-wave signal and the square-wave signal.
5. the LED drive circuit as described in claim 3 or 4, wherein the ripple signal sample circuit further comprise a mirror
Image current source circuit, for the energy of the high-amplitude value part of the square-wave signal to be exported in the form of electric current.
6. the LED drive circuit as described in any one in claim 1-4, wherein the ripple signal compensation circuit include one
Energy-storage travelling wave tube, voltage letter of the energy-storage travelling wave tube based on the collected ripple signal within the corresponding period with ripple current
Number energy storage is carried out, and the energy of the storage is converted into the compensation voltage signal.
7. LED drive circuit as claimed in claim 6, the wherein energy-storage travelling wave tube include capacitance.
8. LED drive circuit as claimed in claim 7, wherein the ripple signal compensation circuit further include first resistor, second
Resistance and diode, the anode of the diode receive the collected ripple signal, the moon of the diode by the first resistor
By the capacity earth, the node of the diode and capacitance provides the compensation voltage signal by the second resistance for pole.
9. LED drive circuit as described in claim 1, the wherein output voltage regulation circuit include a comparator and one
Capacitance, the inverting input of the comparator receive the voltage feedback signal of linear power source circuit output, the positive of the comparator
Input terminal receives the reference voltage, the capacitance connection between the inverting input and output terminal of the comparator, the comparator
Output terminal generates the adjustment signal.
10. LED drive circuit as described in claim 1, the wherein linear power source circuit include a controllable accurate source of stable pressure
Device, first to 3rd resistor, capacitance and an electronic switch, two voltage output ends of the Switching Power Supply with this first
And second resistance series connection, the cathode of the both ends of the second resistance respectively with the controllable accurate source of stable pressure device are connect with anode, this
The series circuit formed after capacitance and the electronic switch and 3rd resistor composition series circuit with first and second resistance is simultaneously
Connection connection, the control terminal of the electronic switch are connected on the node between the first resistor and second resistance, and the controllable accurate is steady
The reference pole of potential source device is connected on the node between the electronic switch and the 3rd resistor, and the both ends of the capacitance connect respectively
To two power inputs of the LED module.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410039919.1A CN104812121B (en) | 2014-01-27 | 2014-01-27 | Led drive circuit |
| PCT/CN2015/070992 WO2015109977A1 (en) | 2014-01-27 | 2015-01-19 | Led drive circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410039919.1A CN104812121B (en) | 2014-01-27 | 2014-01-27 | Led drive circuit |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN104812121A CN104812121A (en) | 2015-07-29 |
| CN104812121B true CN104812121B (en) | 2018-07-06 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201410039919.1A Expired - Fee Related CN104812121B (en) | 2014-01-27 | 2014-01-27 | Led drive circuit |
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| Country | Link |
|---|---|
| CN (1) | CN104812121B (en) |
| WO (1) | WO2015109977A1 (en) |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105188201B (en) * | 2015-08-25 | 2018-07-17 | 北京极澈远技术有限公司 | A kind of high speed light adjusting circuit applied to LED illumination |
| CN106793322B (en) * | 2016-12-30 | 2020-05-19 | 深圳Tcl数字技术有限公司 | LED drive circuit |
| CN106527561B (en) * | 2017-01-04 | 2018-07-17 | 西南应用磁学研究所 | A kind of high-efficiency magnetic tuning device driving circuit of tracking with voltage |
| CN108811225A (en) * | 2017-05-04 | 2018-11-13 | 深圳市帝莱特照明有限公司 | A kind of middle low power intelligent lighting dims color-changed LED driving power without stroboscopic |
| JP7295881B2 (en) | 2018-10-31 | 2023-06-21 | ローム株式会社 | linear power supply circuit |
| CN112423434B (en) * | 2020-11-13 | 2021-10-08 | 浙江大学 | Power supply ripple based multi-path LED lamp brightness bypass detection device and method |
| CN112953220B (en) * | 2021-02-03 | 2022-12-30 | 电子科技大学 | DC-DC converter with current sensing and control |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101039076A (en) * | 2007-04-28 | 2007-09-19 | 电子科技大学 | Voltage-stabilizing switch power source with voltage ripple detection circuit |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101404846B (en) * | 2008-11-17 | 2011-12-28 | 南京智浦芯联电子科技有限公司 | Real-time compensation apparatus for input voltage fluctuation in power LED driving system |
| CN101754540B (en) * | 2010-02-09 | 2012-10-03 | 四川锦明光电股份有限公司 | Drive of light emitting diode (LED) light source |
| CN103259437B (en) * | 2012-02-15 | 2017-05-10 | 欧司朗股份有限公司 | Load actuator and method for reducing output ripple current of load actuator |
| 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 |
-
2014
- 2014-01-27 CN CN201410039919.1A patent/CN104812121B/en not_active Expired - Fee Related
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2015
- 2015-01-19 WO PCT/CN2015/070992 patent/WO2015109977A1/en active Application Filing
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101039076A (en) * | 2007-04-28 | 2007-09-19 | 电子科技大学 | Voltage-stabilizing switch power source with voltage ripple detection circuit |
Also Published As
| Publication number | Publication date |
|---|---|
| WO2015109977A1 (en) | 2015-07-30 |
| CN104812121A (en) | 2015-07-29 |
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