CN103813596B - The method of LED drive circuit and reduction LED current ripple - Google Patents
The method of LED drive circuit and reduction LED current ripple Download PDFInfo
- Publication number
- CN103813596B CN103813596B CN201410085182.7A CN201410085182A CN103813596B CN 103813596 B CN103813596 B CN 103813596B CN 201410085182 A CN201410085182 A CN 201410085182A CN 103813596 B CN103813596 B CN 103813596B
- Authority
- CN
- China
- Prior art keywords
- voltage
- constant
- current
- amplifier
- connects
- 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.)
- Active
Links
Landscapes
- Amplifiers (AREA)
Abstract
The invention provides a kind of method of LED drive circuit and reduction LED current ripple, this LED drive circuit comprises: constant-flow driver, produces the input current that mean value remains unchanged; First electric capacity, its first end connects the first output of this constant-flow driver, and its second end connects the second output of this constant-flow driver and ground connection; Linearity constant current control circuit, be connected between LED load and ground, this LED load after series connection and linearity constant current control circuit and described first Capacitance parallel connection, this linearity constant current control circuit provides the electric current controlled by the external reference voltages preset, and described linearity constant current control circuit and the average voltage of the serial connection point of LED load is controlled as equal with this external reference voltages.The present invention can reduce the current ripples even eliminated in LED load.
Description
Technical field
The present invention relates to LED Driving technique, particularly relate to a kind of method of LED drive circuit and reduction LED current ripple.
Background technology
With reference to figure 1, traditional comprises constant-flow driver 101, output filter capacitor C1 and LED load by the LED drive circuit of Alternating Current Power Supply.General containing low-frequency ac composition in the constant current output signal Iin of constant-flow driver 101, output filter capacitor C1 can filtering radio-frequency component and a part of industrial frequency AC composition.But for the occasion that power factor requires, the industrial frequency AC composition outputting to the electric current of LED load will be larger.Such as, for the mains frequency of conventional 50Hz, the electric current outputting to LED load contains 100Hz power frequency composition, the stroboscopic of 100Hz will be produced like this, this stroboscopic can affect the life-span of LED load, and can cause the visual fatigue of user, easily causes myopia.
Therefore, the working frequency ripple wave how reduced in LED load is urgent problem.
Summary of the invention
The technical problem to be solved in the present invention is to provide a kind of method of LED drive circuit and reduction LED current ripple, can reduce the current ripples even eliminated in LED load.
For solving the problems of the technologies described above, the invention provides a kind of LED drive circuit, comprising:
Constant-flow driver, produces the input current that mean value remains unchanged;
First electric capacity, its first end connects the first output of this constant-flow driver, and its second end connects the second output of this constant-flow driver and ground connection;
Linearity constant current control circuit, be connected between LED load and ground, this LED load after series connection and linearity constant current control circuit and described first Capacitance parallel connection, this linearity constant current control circuit provides the electric current controlled by the external reference voltages preset, and this electric current is not with the change in voltage that be connected in series point of this linearity constant current control circuit with LED load.
According to one embodiment of present invention, this linearity constant current control circuit comprises error amplifier, compensating network and constant-current source circuit, wherein,
The first input end of described error amplifier receives described external reference voltages, and what its second input connected described linearity constant current control circuit and LED load is connected in series a little, calculates the error voltage between this external reference voltages is connected in series point voltage with this;
Described compensating network, its input connects the output of described error amplifier, and the error voltage integration exported described error amplifier is to obtain control voltage;
Described constant-current source circuit, to be connected between described serial connection point and ground and to receive described control voltage, controls the current value of described serial connection point to ground according to described control voltage, and this current value is not changed with the change in voltage of described serial connection point.
According to one embodiment of present invention, described constant-current source circuit is Voltage-controlled Current Source structure.
According to one embodiment of present invention, described constant-current source circuit comprises: the first nmos pass transistor, and its drain electrode connects described serial connection point, and its source ground, its grid receives described control voltage.
According to one embodiment of present invention, described constant-current source circuit comprises:
Amplifier, its first input end receives described control voltage;
Second nmos pass transistor, its drain electrode connects described serial connection point, and its source electrode connects the second input of described amplifier, and its grid connects the output of described amplifier;
Sampling resistor, its first end connects the source electrode of described second nmos pass transistor, its second end ground connection.
According to one embodiment of present invention, described constant-current source circuit comprises:
Voltage overlaying circuit, its first input end receives described control voltage, and its second input receives the reference voltage preset, and described control voltage is superposed to obtain superimposed voltage with described reference voltage;
Amplifier, its first input end receives described superimposed voltage;
Second nmos pass transistor, its drain electrode connects described serial connection point, and its source electrode connects the second input of described amplifier, and its grid connects the output of described amplifier;
Sampling resistor, its first end connects the source electrode of described second nmos pass transistor, its second end ground connection.
According to one embodiment of present invention, described constant-current source circuit comprises:
Amplifying circuit, its input receives described control voltage, zooms in or out described control voltage;
Amplifier, its first input end connects the output of described amplifying circuit;
Second nmos pass transistor, its drain electrode connects described serial connection point, and its source electrode connects the second input of described amplifier, and its grid connects the output of described amplifier;
Sampling resistor, its first end connects the source electrode of described second nmos pass transistor, its second end ground connection.
According to one embodiment of present invention, described constant-current source circuit comprises:
See-saw circuit, its input receives described control voltage, carries out anti-phase to described control voltage;
Amplifier, its first input end connects the output of described see-saw circuit;
Second nmos pass transistor, its drain electrode connects described serial connection point, and its source electrode connects the second input of described amplifier, and its grid connects the output of described amplifier;
Sampling resistor, its first end connects the source electrode of described second nmos pass transistor, its second end ground connection.
According to one embodiment of present invention, the second input of described error amplifier to be a little connected with described serial connection via the second resistance via the first grounding through resistance.
According to one embodiment of present invention, described error amplifier is transconductance type error amplifier.
According to one embodiment of present invention, described compensating network is made up of electric capacity, or is made up of electric capacity and resistance.
According to one embodiment of present invention, described compensating network comprises:
Second electric capacity, its first end connects the output of described error amplifier, its second end ground connection;
3rd resistance, its first end connects the first end of described second electric capacity;
3rd electric capacity, its first end connects the second end of described 3rd resistance, its second end ground connection.
According to one embodiment of present invention, the mean value that the magnitude of voltage of described external reference voltages equals the ripple voltage that described input current produces on described first electric capacity adds default voltage deviation.
Present invention also offers a kind of method reducing LED current ripple, comprising:
Constant-current source circuit is connected between described LED load and ground, this constant-current source circuit after series connection and LED load and the first Capacitance parallel connection;
The voltage being connected in series point of this constant-current source circuit and the LED load of sampling, carries out error and amplifies and obtain error voltage, obtain control voltage to this error voltage integration by this voltage and the external reference voltages preset;
This control voltage is adopted to control the current value of described constant-current source circuit, the magnitude of voltage one_to_one corresponding of this current value and described control voltage and be not connected in series change in voltage a little with described and change.
According to one embodiment of present invention, described external reference voltages is determined in the following way:
Determine the mean value of the ripple voltage that described first electric capacity produces;
The mean value of described ripple voltage adds that default voltage deviation obtains described external reference voltages.
Compared with prior art, the present invention has the following advantages:
The LED drive circuit of the embodiment of the present invention adopts linearity constant current control circuit to connect with LED load, the electric current that this linearity constant current control circuit provides is controlled with the average voltage being connected in series point of LED load by this linearity constant current control circuit, and the average voltage of this serial connection point is set by external reference voltages, through loop compensation, the electric current flowing through LED load is not changed with power frequency, and substantially all flow into filter capacitor with the AC portion of the input current of power frequency change, thus effectively can reduce the current ripples even eliminated in LED load.
Accompanying drawing explanation
Fig. 1 is the structural representation of a kind of LED drive circuit in prior art;
Fig. 2 is the electrical block diagram of the LED drive circuit of first embodiment of the invention;
Fig. 3 is the electrical block diagram of the LED drive circuit of second embodiment of the invention;
Fig. 4 is the electrical block diagram of a kind of constant-current source circuit in the embodiment of the present invention;
Fig. 5 is the electrical block diagram of another kind of constant-current source circuit in the embodiment of the present invention;
Fig. 6 is the electrical block diagram of the LED drive circuit of third embodiment of the invention;
Fig. 7 is the electrical block diagram of the LED drive circuit of fourth embodiment of the invention.
Embodiment
Below in conjunction with specific embodiments and the drawings, the invention will be further described, but should not limit the scope of the invention with this.
First embodiment
With reference to figure 2, the LED drive circuit in the first embodiment comprises constant-flow driver 101, first electric capacity C1 and existing constant-current control circuit 200, and wherein the first electric capacity C1 is also called filter capacitor in this article.
Furthermore, the input current Iin that constant-flow driver 101 remains unchanged for generation of mean value, this input current Iin can contain the alternating component of power frequency.Constant-flow driver 101 can adopt any suitable constant-current drive circuit structure, such as, constant-flow driver 101 shown in Fig. 1.
The first end of the first electric capacity C1 connects the first output of this constant-flow driver 101, and the second end connects the second output of this constant-flow driver 101 and ground connection GND, and in other words, this first electric capacity C1 is connected in parallel on the output port of constant-flow driver 101.First electric capacity C1 is used for filtering, and the voltage at its two ends is denoted as Vin.
Linearity constant current control circuit 200 is connected between LED load and ground GND, and the linearity constant current control circuit 200 after series connection and LED load are in parallel with the first electric capacity C1 again, and linearity constant current control circuit 200 is designated as D point with the point that is connected in series of LED load.Linearity constant current control circuit 200 provides electric current to LED load, and the current value of this electric current is controlled by the external reference voltages VREF1 preset, and the current value of this electric current does not change with the change of the voltage of serial connection point D.
Further, this linearity constant current control circuit 200 can comprise error amplifier 201, compensating network 202 and constant-current source circuit 203.
Wherein, the first input end of error amplifier 201 receives external reference voltages VREF1, second input connects serial connection point D, this error amplifier 201 calculates external reference voltages VREF1 and the error voltage between the voltage being connected in series some D, and this error voltage is exported by the output COMP of error amplifier 201.This error amplifier can be such as the error amplifier of transconductance type error amplifier or other appropriate configuration.
Wherein, external reference voltages VREF1 is preferably and sets in the following way: the magnitude of voltage obtaining the ripple voltage V1 that filter capacitor C1 produces according to the ripple size of the input current of constant-flow driver 101 generation, and the size of this ripple voltage V1 determines the efficiency that LED drive circuit reduces ripple; On the basis of the mean value of ripple voltage V1, add default voltage deviation V2 afterwards, thus obtain the magnitude of voltage of external reference voltages VREF1.V2 is larger for this voltage deviation, and the effect eliminating ripple current is better, but efficiency is also lower.
The input of compensating network 202 connects the output COMP of error amplifier 201, and the error voltage integration exported error amplifier 201 is to obtain control voltage Vcomp.Compensating network 202 can be made up of electric capacity, or also can be made up of electric capacity and resistance.As a nonrestrictive example, this compensating network 202 can comprise the second electric capacity C2, and its first end connects the output COMP of error amplifier 201, its second end ground connection; 3rd resistance R3, its first end connects the first end of the second electric capacity C2; 3rd electric capacity C3, its first end connects second end of the 3rd resistance R3, its second end ground connection.
Constant-current source circuit 203 to be connected between serial connection point D and ground GND and to receive control voltage Vcomp, controls the current value of serial connection point D to ground GND, this current value is not changed with the change in voltage of serial connection D according to control voltage Vcomp.More specifically, when control voltage Vcomp is fixing, the current value of contact D to ground GND does not change with the change in voltage of serial connection point D, thus can realize the object reducing LED load output current ripple.
This constant-current source circuit 203 can be Voltage-controlled Current Source structure, specifically, can provide corresponding electric current under the control of control voltage Vcomp to LED load.
This linearity constant current control circuit 200 entirety is a loop structure, constantly feed back in the course of the work, external reference voltages VREF1 is carried out error amplification with the voltage being connected in series some D by error amplifier 201, control voltage Vcomp is obtained again via compensating network 202 integration, this control voltage Vcomp controls the size of the electric current that constant-current source circuit 203 provides, and can provide fixing current value for given control voltage Vcomp.After loop stability, the mean value of the voltage of serial connection point D is equal with the magnitude of voltage of external reference voltages VREF1, therefore, can be arranged the mean value of the voltage of serial connection point D by the magnitude of voltage arranging external reference voltages VREF1.
In addition, after loop stability, the electric current flowing through LED load equals the mean value of the input AC electric current inputing to constant-flow driver 101, and ripple current flow into filter capacitor C1 substantially completely, thus achieves the object reducing current ripples.
Second embodiment
Substantially similar with reference to the circuit structure shown in the structure of the LED drive circuit of the second embodiment shown in figure 3, Fig. 3 and Fig. 2, also comprise constant-flow driver 101, first electric capacity C1 and linearity constant current control circuit 300.This linearity constant current control circuit 300 comprises error amplifier 301, compensating network 302 and constant-current source circuit 303.
Wherein place's difference is, in the second embodiment, the second input of error amplifier 301 is via the first resistance R1 ground connection, and in addition, the second input of error amplifier 301 is also connected with serial connection point D through the second resistance R2.
The voltage of serial connection point D transfers to the second input of error amplifier 301 voltage via the second resistance R2 is designated as sampled voltage V
sAMPLE.Sampled voltage V
sAMPLEfollowing formulae discovery can be adopted: V
sAMPLE=V
d* R1/(R1+R2), wherein, V
dfor the magnitude of voltage of serial connection point D, R1 and R2 is the resistance value of the first resistance R1 and the second resistance R2 respectively.
The structure of compensating network 302 is identical with the first embodiment, also comprises the second electric capacity C2, the 3rd electric capacity C3 and the 3rd resistance R3.Compensating network 302 can filtering power frequency component, and obtain control voltage Vcomp, control voltage Vcomp is direct current signal or is similar to direct current signal.
Other place's difference is, gives the concrete structure of constant-current source circuit 303 in the second embodiment, and this constant-current source circuit 303 comprises: the first nmos pass transistor N1, and its drain electrode connects serial connection point D, its source ground GND, and its grid receives control voltage Vcomp.When control voltage Vcomp is constant, the source-drain current of the first nmos pass transistor N1 is relevant to the source-drain voltage of the first nmos pass transistor N1, and therefore, the characteristic of the constant-current source circuit 303 shown in Fig. 3 is not ideal.For this problem, can improve the structure of constant-current source circuit 303.
Show a kind of preferred constant-current source circuit with reference to figure 4, Fig. 4, this constant-current source circuit comprises: amplifier AMP1, the second nmos pass transistor N2 and sampling resistor Rcs.Wherein, the first input end of amplifier AMP1 receives control voltage Vcomp; The drain electrode of the second nmos pass transistor N2 connects serial connection point D, and its source electrode connects second input of amplifier AMP1, and its grid connects the output of amplifier AMP1; The first end of sampling resistor Rcs connects the source electrode of the second nmos pass transistor N2, its second end ground connection.The electric current that the constant-current source circuit of this structure provides can adopt following formulae discovery: Vcomp/Rcs, and wherein Vcomp is the magnitude of voltage of control voltage Vcomp, and Rcs is the resistance value of sampling resistor Rcs.The constant-current source circuit compared in the constant-current source circuit 303, Fig. 4 in Fig. 3 has better characteristic.
Show another kind of preferred constant-current source circuit with reference to figure 5, Fig. 5, this constant-current source circuit comprises: voltage overlaying circuit 51, amplifier AMP1, the second nmos pass transistor N2 and sampling resistor Rcs.Wherein, the first input end of voltage overlaying circuit 51 receives control voltage Vcomp, and its second input receives the reference voltage VREF3 preset, and is superposed to obtain superimposed voltage Vcomp1 by control voltage Vcomp with this reference voltage VREF3; The first input end of amplifier AMP1 receives superimposed voltage Vcomp1; The drain electrode of the second nmos pass transistor N2 connects serial connection point D, and its source electrode connects second input of amplifier AMP1, and its grid connects the output of amplifier AMP1; The first end of sampling resistor Rcs connects the source electrode of the second nmos pass transistor N2, its second end ground connection GND.
In the structure shown in Fig. 5, constant current value is controlled by superimposed voltage Vcomp1, can be obtained: Vcomp1/Rcs by following formulae discovery.This superimposed voltage Vcomp1 can use adder to obtain, and subtracter also can be adopted to obtain.Due to the fixed value that reference voltage VREF3 is default, therefore for fixing control voltage Vcomp, there is a unique constant current value Vcomp1/Rcs corresponding with it.
3rd embodiment
Substantially similar with reference to the circuit structure shown in the structure of the LED drive circuit of the 3rd embodiment shown in figure 6, Fig. 6 and Fig. 3, also comprise constant-flow driver 101, first electric capacity C1 and linearity constant current control circuit 400.This linearity constant current control circuit 400 comprises error amplifier 401, compensating network 402 and constant-current source circuit 403.
Essential difference is, in the third embodiment, constant-current source circuit 403 have employed another kind of preferred circuit structure.This constant-current source circuit 403 comprises amplifying circuit 4031, amplifier 4032, second nmos pass transistor N2 and sampling resistor Rcs.
Wherein, the input of amplifying circuit 4031 receives control voltage Vcomp, zooms in or out control voltage Vcomp; The first input end of amplifier 4032 connects the output of amplifying circuit 4031; The drain electrode of the second nmos pass transistor N2 connects serial connection point D, and its source electrode connects the second input of amplifier 4032, and its grid connects the output of amplifier 4032; The first end of sampling resistor Rcs connects the source electrode of the second nmos pass transistor N2, its second end ground connection GND.Control voltage Vcomp goes after zooming in or out via amplifying circuit 4031 to control the size of constant current value again, and the constant current value that constant-current source circuit 403 is provided remains and controlled by control voltage Vcomp.
4th embodiment
Substantially similar with reference to the circuit structure shown in the structure of the LED drive circuit of the 4th embodiment shown in figure 7, Fig. 7 and Fig. 6, also comprise constant-flow driver 101, first electric capacity C1 and linearity constant current control circuit 500.This linearity constant current control circuit 500 comprises error amplifier 501, compensating network 502 and constant-current source circuit 503.
Essential difference is, in the fourth embodiment, the first input end of error amplifier 501 is positive input terminal, second input is negative input end, namely the positive input terminal of this error amplifier 501 receives external reference voltages VREF2, and its negative input end is via the first resistance R1 ground connection and via a second resistance R2 connection serial connection point D.Correspondingly, constant-current source circuit 503 have employed see-saw circuit 5031, and this constant-current source circuit 503 comprises see-saw circuit 5031, amplifier 5032, second nmos pass transistor N2 and sampling resistor Rcs.
Wherein, the input of see-saw circuit 5031 receives control voltage Vcomp, carries out anti-phase to control voltage Vcomp; The first input end of amplifier 5032 connects the output of see-saw circuit 5031; The drain electrode of the second nmos pass transistor N2 connects serial connection point D, and its source electrode connects the second input of amplifier 5032, and its grid connects the output of amplifier 5032; The first end of sampling resistor Rcs connects the source electrode of the second nmos pass transistor N2, its second end ground connection GND.After control voltage Vcomp is anti-phase via see-saw circuit 4031, use anti-phase control voltage Vcomp to control constant current value, the effect of the elimination LED ripple voltage identical with Fig. 6 can be realized.
No matter it should be noted that, be which embodiment above-mentioned, and the magnitude of voltage of the external reference voltages that error amplifier receives can be determined according to the mean value of the ripple voltage that the first electric capacity produces.Specifically, first determine the magnitude of voltage of the ripple voltage V1 on the first electric capacity, on the basis of the mean value of this ripple voltage V1, add predeterminated voltage deviation V2 afterwards, thus obtain the magnitude of voltage of external reference voltages.V2 is larger for this voltage deviation, and the effect eliminating ripple current is better, but efficiency is also lower.
In addition, present invention also offers a kind of method reducing LED current ripple, the method comprises the steps:
Constant-current source circuit is connected between LED load and ground, this constant-current source circuit after series connection and LED load again with the first Capacitance parallel connection, the constant current value of the electric current that this constant-current source circuit provides controls by loop;
According to the size of electric current AC ripple, obtain the mean value of the ripple voltage V1 that the first electric capacity produces, the mean value of this ripple voltage V1 determines the efficiency reducing ripple voltage;
The mean value basis of ripple voltage V1 adding, default voltage deviation V2 is to obtain external reference voltages VREF1, and V2 is larger for this voltage deviation, and the effect eliminating ripple current is better, but efficiency is lower;
Sampling obtains constant-current source circuit and the voltage be connected in series on point of LED load, and namely obtain the voltage dropped on constant-current source circuit, this voltage and external reference voltages VREF1 are carried out error amplification, and integration obtains control voltage Vcomp;
This control voltage Vcomp is adopted to control the constant current value of constant-current source circuit, a fixing constant current value is obtained for given error voltage Vcomp, the namely magnitude of voltage one_to_one corresponding of this constant current value and control voltage Vcomp, do not change with the change in voltage being connected in series point of LED load with constant-current source circuit, thus the electric current flowing through LED load is remained unchanged.
After loop stability, the electric current flowing through LED load equals the mean value of the input AC electric current inputting constant-flow driver, and ripple current flow on the first electric capacity substantially completely, achieves the object reducing current ripples.
The above is only preferred embodiment of the present invention, not does any pro forma restriction to the present invention.Therefore, every content not departing from technical solution of the present invention, just according to technical spirit of the present invention to any simple amendment made for any of the above embodiments, equivalent conversion, all still belong in the protection range of technical solution of the present invention.
Claims (13)
1. a LED drive circuit, is characterized in that, comprising:
Constant-flow driver, produces the input current that mean value remains unchanged;
First electric capacity, its first end connects the first output of this constant-flow driver, and its second end connects the second output of this constant-flow driver and ground connection;
Linearity constant current control circuit, be connected between LED load and ground, this LED load after series connection and linearity constant current control circuit and described first Capacitance parallel connection, this linearity constant current control circuit provides the electric current controlled by the external reference voltages preset, this electric current is not with the change in voltage that be connected in series point of this linearity constant current control circuit with LED load, and the mean value that the magnitude of voltage of described external reference voltages equals the ripple voltage that described input current produces on described first electric capacity adds default voltage deviation.
2. LED drive circuit according to claim 1, is characterized in that, this linearity constant current control circuit comprises error amplifier, compensating network and constant-current source circuit, wherein,
The first input end of described error amplifier receives described external reference voltages, and what its second input connected described linearity constant current control circuit and LED load is connected in series a little, calculates the error voltage between this external reference voltages is connected in series point voltage with this;
Described compensating network, its input connects the output of described error amplifier, and the error voltage integration exported described error amplifier is to obtain control voltage;
Described constant-current source circuit, to be connected between described serial connection point and ground and to receive described control voltage, controls the current value of described serial connection point to ground according to described control voltage, and this current value is not changed with the change in voltage of described serial connection point.
3. LED drive circuit according to claim 2, is characterized in that, described constant-current source circuit is Voltage-controlled Current Source structure.
4. LED drive circuit according to claim 3, is characterized in that, described constant-current source circuit comprises: the first nmos pass transistor, and its drain electrode connects described serial connection point, and its source ground, its grid receives described control voltage.
5. LED drive circuit according to claim 3, is characterized in that, described constant-current source circuit comprises:
Amplifier, its first input end receives described control voltage;
Second nmos pass transistor, its drain electrode connects described serial connection point, and its source electrode connects the second input of described amplifier, and its grid connects the output of described amplifier;
Sampling resistor, its first end connects the source electrode of described second nmos pass transistor, its second end ground connection.
6. LED drive circuit according to claim 3, is characterized in that, described constant-current source circuit comprises:
Voltage overlaying circuit, its first input end receives described control voltage, and its second input receives the reference voltage preset, and described control voltage is superposed to obtain superimposed voltage with described reference voltage;
Amplifier, its first input end receives described superimposed voltage;
Second nmos pass transistor, its drain electrode connects described serial connection point, and its source electrode connects the second input of described amplifier, and its grid connects the output of described amplifier;
Sampling resistor, its first end connects the source electrode of described second nmos pass transistor, its second end ground connection.
7. LED drive circuit according to claim 3, is characterized in that, described constant-current source circuit comprises:
Amplifying circuit, its input receives described control voltage, zooms in or out described control voltage;
Amplifier, its first input end connects the output of described amplifying circuit;
Second nmos pass transistor, its drain electrode connects described serial connection point, and its source electrode connects the second input of described amplifier, and its grid connects the output of described amplifier;
Sampling resistor, its first end connects the source electrode of described second nmos pass transistor, its second end ground connection.
8. LED drive circuit according to claim 3, is characterized in that, described constant-current source circuit comprises:
See-saw circuit, its input receives described control voltage, carries out anti-phase to described control voltage;
Amplifier, its first input end connects the output of described see-saw circuit;
Second nmos pass transistor, its drain electrode connects described serial connection point, and its source electrode connects the second input of described amplifier, and its grid connects the output of described amplifier;
Sampling resistor, its first end connects the source electrode of described second nmos pass transistor, its second end ground connection.
9. the LED drive circuit according to any one of claim 4 to 8, is characterized in that, the second input of described error amplifier is via the first grounding through resistance and be a little connected with described serial connection via the second resistance.
10. LED drive circuit according to claim 2, is characterized in that, described error amplifier is transconductance type error amplifier.
11. LED drive circuits according to claim 2, is characterized in that, described compensating network is made up of electric capacity, or are made up of electric capacity and resistance.
12. LED drive circuits according to claim 2, is characterized in that, described compensating network comprises:
Second electric capacity, its first end connects the output of described error amplifier, its second end ground connection;
3rd resistance, its first end connects the first end of described second electric capacity;
3rd electric capacity, its first end connects the second end of described 3rd resistance, its second end ground connection.
13. 1 kinds of methods reducing LED current ripple, is characterized in that, comprising:
Constant-current source circuit is connected between described LED load and ground, this constant-current source circuit after series connection and LED load and the first Capacitance parallel connection;
The voltage being connected in series point of this constant-current source circuit and the LED load of sampling, carries out error and amplifies and obtain error voltage, obtain control voltage to this error voltage integration by this voltage and the external reference voltages preset;
This control voltage is adopted to control the current value of described constant-current source circuit, the magnitude of voltage one_to_one corresponding of this current value and described control voltage and be not connected in series change in voltage a little with described and change;
Wherein, described external reference voltages is determined in the following way: the mean value determining the ripple voltage that described first electric capacity produces; The mean value of described ripple voltage adds that default voltage deviation obtains described external reference voltages.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410085182.7A CN103813596B (en) | 2014-03-10 | 2014-03-10 | The method of LED drive circuit and reduction LED current ripple |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410085182.7A CN103813596B (en) | 2014-03-10 | 2014-03-10 | The method of LED drive circuit and reduction LED current ripple |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN103813596A CN103813596A (en) | 2014-05-21 |
| CN103813596B true CN103813596B (en) | 2016-02-24 |
Family
ID=50709640
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201410085182.7A Active CN103813596B (en) | 2014-03-10 | 2014-03-10 | The method of LED drive circuit and reduction LED current ripple |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN103813596B (en) |
Families Citing this family (15)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103987178B (en) * | 2014-05-28 | 2017-12-19 | 杭州士兰微电子股份有限公司 | LED driving methods, drive circuit and its output current ripple controller |
| CN105491734A (en) * | 2014-09-15 | 2016-04-13 | 上海俪德照明科技股份有限公司 | LED single-segment constant-current light-modulation drive circuit and method |
| CN105657925B (en) * | 2014-11-14 | 2018-05-22 | 苏州力生美半导体有限公司 | Integrated circuit |
| CN104883793B (en) * | 2015-06-09 | 2017-06-16 | 南京矽力杰半导体技术有限公司 | A kind of multipath LED constant current drive circuit and driving method |
| CN105406697B (en) | 2015-12-22 | 2018-12-25 | 矽力杰半导体技术(杭州)有限公司 | Ripple suppression circuit, method and the LED light using it |
| CN105848334B (en) * | 2016-03-26 | 2018-03-02 | 中山市德源照明电器有限公司 | L ED constant current control power supply |
| CN106132031B (en) * | 2016-08-20 | 2018-07-17 | 杰华特微电子（杭州）有限公司 | A kind of ripple eliminates circuit, ripple removing method and applies its LED circuit |
| CN106658862B (en) * | 2017-01-17 | 2018-03-27 | 厦门奇力微电子有限公司 | Current ripples eliminate circuit and its method |
| CN106879109B (en) * | 2017-02-09 | 2018-11-09 | 上海晶丰明源半导体股份有限公司 | Controller, chip and method for eliminating LED drive system current ripples |
| CN106658866B (en) * | 2017-02-09 | 2018-12-25 | 上海晶丰明源半导体股份有限公司 | For eliminating the controller, chip and method of LED drive system current ripples |
| CN106879127B (en) * | 2017-04-19 | 2018-10-26 | 上海晶丰明源半导体股份有限公司 | A kind of controller, chip and the method for double LED drive systems |
| CN107979899A (en) * | 2017-12-27 | 2018-05-01 | 苏州菲达旭微电子有限公司 | A kind of linear general pump feeds constant-current circuit and has its LED light |
| CN109167506A (en) * | 2018-10-26 | 2019-01-08 | 苏州菲达旭微电子有限公司 | A kind of current filtering circuit |
| CN109743811A (en) * | 2018-12-24 | 2019-05-10 | 欧普照明股份有限公司 | A kind of current control circuit |
| CN109890101B (en) * | 2019-01-29 | 2021-06-08 | 威创集团股份有限公司 | Linear constant current circuit |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1909048A (en) * | 2005-08-01 | 2007-02-07 | 哈利盛东芝照明株式会社 | Led drive device |
| CN101431845A (en) * | 2007-11-05 | 2009-05-13 | 深圳桑达百利电器有限公司 | Driving method and circuit for LED lamp string |
| CN201374835Y (en) * | 2009-02-23 | 2009-12-30 | 张征 | LED lamp linear constant current driving module |
| CN102664524A (en) * | 2012-05-09 | 2012-09-12 | 无锡创想华微科技有限公司 | Constant current DC (Direct Current)-DC converter utilizing digital PWM (Pulse-Width Modulation) control and constant current LED (Light Emitting Diode) drive DC-DC converter |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7233115B2 (en) * | 2004-03-15 | 2007-06-19 | Color Kinetics Incorporated | LED-based lighting network power control methods and apparatus |
| CN201541365U (en) * | 2009-09-08 | 2010-08-04 | 奇瑞汽车股份有限公司 | Constant current source used for driving a plurality of LEDs |
| CN201967214U (en) * | 2011-02-22 | 2011-09-07 | 英飞特电子（杭州）有限公司 | Constant current driving circuit for LED (light-emitting diode) lamp |
| WO2013138972A1 (en) * | 2012-03-19 | 2013-09-26 | Ye Jun | Led drive chip and circuit with power compensation |
| CN203313490U (en) * | 2013-06-04 | 2013-11-27 | 上海晶丰明源半导体有限公司 | LED current ripple elimination driving circuit |
| CN103533719A (en) * | 2013-10-29 | 2014-01-22 | 上海晶丰明源半导体有限公司 | Triode-based light-emitting diode (LED) current ripple elimination driving circuit |
| CN203708609U (en) * | 2014-03-10 | 2014-07-09 | 杭州士兰微电子股份有限公司 | LED driving circuit |
-
2014
- 2014-03-10 CN CN201410085182.7A patent/CN103813596B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1909048A (en) * | 2005-08-01 | 2007-02-07 | 哈利盛东芝照明株式会社 | Led drive device |
| CN101431845A (en) * | 2007-11-05 | 2009-05-13 | 深圳桑达百利电器有限公司 | Driving method and circuit for LED lamp string |
| CN201374835Y (en) * | 2009-02-23 | 2009-12-30 | 张征 | LED lamp linear constant current driving module |
| CN102664524A (en) * | 2012-05-09 | 2012-09-12 | 无锡创想华微科技有限公司 | Constant current DC (Direct Current)-DC converter utilizing digital PWM (Pulse-Width Modulation) control and constant current LED (Light Emitting Diode) drive DC-DC converter |
Also Published As
| Publication number | Publication date |
|---|---|
| CN103813596A (en) | 2014-05-21 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN103813596B (en) | The method of LED drive circuit and reduction LED current ripple | |
| CN105406697B (en) | Ripple suppression circuit, method and the LED light using it | |
| CN105322777B (en) | Circuit of power factor correction for power electronic system | |
| CN103987178B (en) | LED driving methods, drive circuit and its output current ripple controller | |
| CN103023300B (en) | Constant-current control circuit capable of correcting power factors and power factor correcting circuit | |
| CN203708609U (en) | LED driving circuit | |
| CN103841728B (en) | Multichannel loading balanced steady flow control circuit, corresponding electrical combination and control method | |
| CN108923627B (en) | Power supply following filter circuit | |
| CN103036427A (en) | Synchronous buck converter | |
| CN103944375A (en) | PFC control circuit and PFC circuit with same used | |
| CN103747599B (en) | Current stabilization control circuit, corresponding electrical combination and current stabilization control method | |
| CN203851350U (en) | LED driving circuit and output current ripple controller thereof | |
| CN103023323B (en) | Average inductive current type voltage control method and variable reference voltage generating device used by method | |
| CN205847205U (en) | A kind of automatic gain control circuit based on photoconductive resistance | |
| CN103699166A (en) | Direct-current (DC)-DC output voltage dynamic regulation circuit | |
| CN106160688A (en) | A kind of automatic gain control circuit based on photoconductive resistance | |
| CN103916020B (en) | Switching Power Supply and control circuit thereof | |
| CN106605182B (en) | For the device for the DC current for producing the power circuit for flowing into load | |
| CN207083253U (en) | A kind of adaptive fast response circuit and LED drive circuit | |
| CN102594125A (en) | Secondary power supply circuit for MOA resistive current detecting system | |
| CN202565159U (en) | PFC control circuit capable of flexibly boosting voltage | |
| CN103889121B (en) | A kind of ripple current suppresses circuit | |
| CN203840596U (en) | Ripple current suppression circuit and LED circuit | |
| CN104184425B (en) | The D-type audio power amplifier of single ended input | |
| CN109002074A (en) | Linear voltage-stabilizing circuit, method for stabilizing voltage and the electric power management circuit using it |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant |