CN102006698B - Control method for avoiding flicker effect and illumination device - Google Patents
Control method for avoiding flicker effect and illumination device Download PDFInfo
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- CN102006698B CN102006698B CN2009101706355A CN200910170635A CN102006698B CN 102006698 B CN102006698 B CN 102006698B CN 2009101706355 A CN2009101706355 A CN 2009101706355A CN 200910170635 A CN200910170635 A CN 200910170635A CN 102006698 B CN102006698 B CN 102006698B
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Abstract
The invention discloses a control method for avoiding a flicker effect and an illumination device. The control method for avoiding the flicker effect is applied to an illumination light source module and comprises the following steps of: detecting the change condition of a drive current in the illumination light source module to generate a current detection signal; regulating a variable reference voltage according to the current detection signal; acquiring a feedback voltage from the illumination light source module; generating a voltage control signal according to the feedback voltage and the variable reference voltage; and generating an output voltage according to the voltage control signal to drive the illumination light source module.
Description
Technical field
The present invention relates to a kind of control method and light-emitting device, particularly relate to a kind of capable of dynamic and detect load current, with control method and the light-emitting device of avoiding scintillation effect.
Background technology
Along with the arriving of energy crisis and the new line of environmental consciousness, energy-conservation and demand environmental protection becomes the subject under discussion of global common concern now.The light source that uses compared to tradition, light-emitting diode (Light EmittingDiode, LED) due to have power saving, assembly life-span long, abundant without mercury, colour gamut, need not warm up the lamp time and the advantage such as reaction speed is fast, therefore, light-emitting diode has been widely used in showing and illuminating light source.In addition, can be made into the assembly of minimum or array due to characteristics such as little, lightweight, the anti-collision of volume of light-emitting diode, suitable volume production, easy fit applications demands, therefore light-emitting diode is except being applied to outdoor various display and traffic signal light, also can be applicable on various electronic product or portable product, such as the screen back light source of liquid crystal display, mobile phone, portable computer and personal digital assistant etc.
Please refer to Fig. 1, Fig. 1 is the schematic diagram of an existing LED driving circuit 10.LED driving circuit 10 is used for driving a LED light-source module 102.As shown in Figure 1, LED light-source module 102 includes m the C of light-emitting diode group arranged side by side
1～C
m, and each light-emitting diode serial includes the light-emitting diode of n serial connection.LED driving circuit 10 includes an electric pressure converter 104, a current source 106, a pwm unit 108 and a control unit 110.Electric pressure converter 104 is used to provide a driving voltage V
DTo LED light-source module 102.Current source 106 is used to provide drive current I
D1～I
DmTo LED light-source module 102.Pwm unit 108 is used for according to a light modulation signal S
D, carry out dimmer procedure.Generally speaking, at the C of each light-emitting diode group
1～C
mHave its corresponding head space voltage (Headroomvoltage) V on path
HR1～V
HRm, represent the C of each light-emitting diode group
1～C
mOn path, can be for the magnitude of voltage of current source 106.In practical application, for brightness and the power consumption of stably controlling light-emitting diode, usually can make the electric current of the light-emitting diode of flowing through keep stablizing constant (is drive current I
D1～I
DmKeep stablizing constant).Yet due to impact or other any factor of non-ideal factor on technique, the cross-pressure of each light-emitting diode is not identical with making, and causes head space voltage V
HR1～V
HRmBe not quite similar.In the case, head space overtension or too low, all have not good impact for LED driving circuit 10, and for instance, the head space overtension, can expend too much voltage on current source 106; Otherwise the head space brownout, will cause current source 106 to operate in unsuitable state, and can't stablize the drive current that provides required.
Therefore, in Fig. 1, prior art is to control electric pressure converter 104 by the control unit 110 of negative feedback to change driving voltage V
D, make head space voltage be adjusted to a suitable definite value.Control unit 110 includes a voltage selector 112, an error amplifier 114 and a switching controller 116.Voltage selector 112 is coupled to the C of each light-emitting diode group
1～C
mOutput, be used for selecting head space voltage V
HR1～V
HRmOne of them, be used as a feedback voltage V
FB, and with feedback voltage V
FBAn and preset reference voltage V
REFNegative input end and the positive input terminal of difference error originated from input amplifier 114.Error amplifier 114 is according to feedback voltage V
FBAnd preset reference voltage V
REFDifference, produce an error signal S
ESwitching controller 116 can be according to error signal S
E, produce one and control signal S
C, control electric pressure converter 104 and carry out voltage transitions, with outputting drive voltage V
DThat is to say, as the C of each light-emitting diode group
1～C
mCorresponding head space voltage V
HR1～V
HRmWhen too low, error amplifier 114 can produce error signal S
ETo switching controller 116, signal S is controlled in switching controller 116 and then utilization
C, make electric pressure converter 104 improve driving voltage V
DThus, at drive current I
D1～I
DmImmobilize, and in the situation that also can not change of the cross-pressure on each light-emitting diode, by control unit 110, control and promote driving voltage V
D, head space voltage V
HR1～V
HRmAlso can and then promote, become the relation of positive change between the two, in like manner, vice versa.In other words, at the stable drive current I that supplies
D1～I
DmUnder, LED driving circuit 10 can be feedback and follow the trail of by control unit 110, and it (is preset reference voltage V that head space voltage is locked in a rational magnitude of voltage
REF).
Yet, in many cases, still have the situation of electric current variation by the electric current of light-emitting diode, for instance, when carrying out dimmer procedure, normally utilize the size of current of adjusting by light-emitting diode (that is to adjust drive current I
D1～I
DmSize) change the brightness of light-emitting diode.In the case, due to drive current I
D1～I
DmCan change, make the cross-pressure of light-emitting diode along with variation.Therefore, in aforementioned prior art, if only by the preset reference voltage V with fixing
REFrelatively adjust driving voltage V
D, may follow the trail of the time because of tediously long back coupling, and can't be in real time with driving voltage V
DBe promoted to suitable level, cause feedbacking during this section of following the trail of, current source 106 meeting excuse section space voltages are not enough, and enough drive currents can't be provided, and therefore light-emitting diode will produce scintillation.
Summary of the invention
Therefore, main purpose of the present invention is to provide control method and the light-emitting device that can avoid scintillation effect.
The present invention discloses a kind of control method of avoiding scintillation effect, is used for an illuminating source module, includes the situation of change of a drive current that detects this illuminating source module of flowing through, to produce a current detecting signal; , according to this current detecting signal, adjust a variable reference voltage; , from this illuminating source module, obtain a feedback voltage; , according to this feedback voltage and this variable reference voltage, produce a voltage control signal; And, according to this voltage control signal, produce an output voltage, to drive this illuminating source module.
The present invention also discloses a kind of light-emitting device, includes: an electric pressure converter is used for converting an input voltage to an output voltage according to a voltage control signal; One illuminating source module, be coupled to this electric pressure converter; One variable current source, be coupled to this illuminating source module, is used to provide a drive current, to drive this illuminating source module; And a control unit, be coupled to this illuminating source module and this electric pressure converter, use from this illuminating source module, obtain a feedback voltage, and detect the situation of change of this drive current of this illuminating source module of flowing through, to produce a current detecting signal; Wherein, this control unit, according to this current detecting signal, is adjusted a variable reference voltage, and, according to this feedback voltage and this variable reference voltage, is produced this voltage control signal to this electric pressure converter.
The present invention also discloses a kind of control method of avoiding scintillation effect, is used for an illuminating source module, includes: detect the situation of change of a drive current that provides on a variable current source, to produce a current detecting signal; , according to this current detecting signal, adjust a variable reference voltage; , from this illuminating source module, obtain a feedback voltage; , according to this feedback voltage and this variable reference voltage, produce a voltage control signal; And, according to this voltage control signal, produce an output voltage, to drive this illuminating source module.
The present invention also discloses a kind of light-emitting device, includes: an electric pressure converter is used for converting an input voltage to an output voltage according to a voltage control signal; One illuminating source module, be coupled to this electric pressure converter; One variable current source, be coupled to this illuminating source module, is used for producing a drive current, to drive this illuminating source module; And a control unit, be coupled to this variable current source and this electric pressure converter, use from this illuminating source module, obtain a feedback voltage, and the situation of change of this drive current that provides on this variable current source is provided, to produce a current detecting signal; Wherein, this control unit, according to this current detecting signal, is adjusted a variable reference voltage, and, according to this feedback voltage and this variable reference voltage, is produced this voltage control signal to this electric pressure converter.
Description of drawings
Fig. 1 is the schematic diagram of an existing LED driving circuit.
Fig. 2 is the schematic diagram of the embodiment of the present invention one light-emitting device.
Fig. 3 is the schematic diagram of the embodiment of the present invention one flow process.
Fig. 4 is the schematic diagram of the embodiment of the present invention one light-emitting device.
Fig. 5 is an embodiment schematic diagram of the variable current source in Fig. 4.
Fig. 6 is the schematic diagram of the embodiment of the present invention one flow process.
Fig. 7 is an embodiment schematic diagram of the reference voltage transducer in Fig. 2.
Fig. 8 is an embodiment schematic diagram of the reference voltage transducer in Fig. 4.
The reference numeral explanation
10 LED driving circuit
102 LED light-source modules
104,202,402 electric pressure converters
106 current sources
108 pwm unit
110 control units
112,210,410 voltage selectors
114,218,418 error amplifiers
116,220,420 switching controllers
20,40 light-emitting devices
204,404 illuminating source modules
206,406 variable current sources
208,408 control units
212,412 current detectors
214,414 arithmetic elements
216,416 reference voltage transducers
30,60 flow processs
300、302、304、306、308、
310、312、602、604、606、
608,610,612 steps
502 variable current mirrors
504 current drives assemblies
C
1～C
mLight-emitting diode group
I
D1～I
DmDrive current
I
L1～I
LmLoad current
V
DDriving voltage
V
FBFeedback voltage
V
HR1～V
HRmHead space voltage
V
INInput voltage
V
REFPreset reference voltage
V
REF_VVariable reference voltage
S
CThe voltage control signal
S
EThe error voltage signal
S
LThe current detecting signal
S
VReference voltage conversion signal
Embodiment
Please refer to Fig. 2, Fig. 2 is the schematic diagram of the embodiment of the present invention one light-emitting device 20.Light-emitting device 20 includes an electric pressure converter 202, an illuminating source module 204, a variable current source 206 and a control unit 208.Wherein, light-emitting device 20 is applicable to the light source of any kind.Electric pressure converter 202 is used for according to a voltage control signal S
C, with an input voltage V
INConvert an output voltage V to
D, to provide to illuminating source module 204.Illuminating source module 204 is coupled to electric pressure converter 204.Be noted that in the present embodiment, illuminating source module 204 includes the C of light-emitting diode group
1～C
m, but, not as limit, also a light-emitting diode group can only be arranged.On the other hand, because light-emitting diode is a current drives assembly, its luminosity is directly proportional to the drive current size, that is drive current is larger, and the luminosity of light-emitting diode is also just larger.Generally speaking, be the identical requirement that reaches same brightness of electric current of asking each light-emitting diode of flowing through, therefore, in the present embodiment, each light-emitting diode group includes the light-emitting diode that n series system couples, but the C of light-emitting diode group
1～C
mBe not confined to the light-emitting diode of n serial connection, in other words, each light-emitting diode group also can only comprise single light-emitting diode.In addition, variable current source 206 is coupled to illuminating source module 204, is used to provide the load current I of each light-emitting diode group that flows through
L1～I
Lm, to drive illuminating source module 204.Control unit 208 is coupled to illuminating source module 204 and electric pressure converter 202, is used for self-luminous light source module 204, obtains a feedback voltage V
FB, and detect the load current I of the illuminating source module 204 of flowing through
L1～I
LmSituation of change, to produce a current detecting signal S
LThen, control unit is according to current detecting signal S
L, adjust a variable reference voltage V
REF_V, and according to feedback voltage V
FBAnd variable reference voltage V
REF_V, produce voltage control signal S
CTo electric pressure converter 202.In other words, control unit 208 detects the load current I of the illuminating source module 204 of flowing through in real time
L1～I
LmSituation of change, dynamically adjust variable reference voltage V
REF_V, and then control electric pressure converter 202 and change out suitable output voltage V in real time
D, to provide to illuminating source module 204.
Further illustrate control unit 208, please continue with reference to figure 2.Control unit 208 includes a voltage selector 210, a current detector 212, an arithmetic element 214, a reference voltage transducer 216, an error amplifier 218 and a switching controller 220.Voltage selector 210 is coupled to illuminating source module 204, is used in corresponding to the C of each light-emitting diode group
1～C
mHead space voltage V
HR1～V
HRmIn, select feedback voltage V
FB Current detector 212 is coupled to the illuminating source module, is used for detecting load current I
L1～I
LmSituation of change, detect signal S with generation current
L Arithmetic element 214 is coupled to current detector 212, is used for according to current detecting signal S
L, produce a reference voltage conversion signal S
V Reference voltage transducer 216 is coupled to arithmetic element 214, is used for according to reference voltage conversion signal S
V, produce variable reference voltage V
REF_VTherefore, in current detecting signal S
LIndication load current I
L1～I
LmWhile changing, arithmetic element 214 can be by reference to voltage transitions signal S
V, notification reference electric pressure converter 216 produces required variable reference voltage V
REF_VFor instance, in current detecting signal indication load current I
L1～I
LmWhile becoming large, arithmetic element 214 can be heightened variable reference voltage V by notification reference electric pressure converter 216
REF_VIn like manner, in current detecting signal indication load current I
L1～I
LmWhile diminishing, notification reference electric pressure converter 216 reduces variable reference voltage V
REF_V
Further, a positive input terminal of error amplifier 218 and a negative input end are respectively coupled to reference voltage transducer 216 and voltage selector 210, are used for according to variable reference voltage V
REF_VAnd feedback voltage V
FB, produce an error voltage signal S
ESwitching controller 220 is coupled to 202 of an output of error amplifier 218 and electric pressure converters, is used for according to error voltage signal S
E, produce voltage control signal S
C, to provide to electric pressure converter.In the case, in feedback voltage V
FBGreater than or less than variable reference voltage V
REF_VThe time, error amplifier 218 can, according to difference between the two, produce error voltage signal S
ENotify switching controller 220, switching controller 220 produces voltage control signal S more according to this
C, to heighten or to reduce output voltage V
DIn brief, control unit 208 can detect load current in real time to be changed, and then dynamically adjusts the reference voltage of error originated from input amplifier 218, to reach in real time and effectively to complete to feedback and follow the trail of to suitable output voltage V
D
Therefore, the present invention can detect the load current I of the illuminating source module 204 of flowing through in real time by control unit 208
L1～I
LmSituation of change, dynamically adjust variable reference voltage V
REF_V, and then control electric pressure converter 202 and change out suitable output voltage V in real time
DThus, when the situation of load current variation is arranged, can effectively avoid excuse section space voltage to be compressed into too small, make variable current source 206 that enough load currents can't be provided, and cause illuminating source module 204 that scintillation occurs, also can excuse section space voltage not too high and expend too much voltage loss on variable current source 206, and reduce the global voltage conversion efficiency.
Function mode about light-emitting device 20, please refer to Fig. 3, and Fig. 3 is the schematic diagram of the embodiment of the present invention one flow process 30.Flow process 30 comprises the following step:
Step 300: start.
Step 302: the load current I that detects the illuminating source module 204 of flowing through
L1～I
LmSituation of change, to produce a current detecting signal S
L
Step 304: according to current detecting signal S
L, adjust a variable reference voltage V
REF_V
Step 306: self-luminous light source module 204, obtain a feedback voltage V
FB
Step 308: according to feedback voltage V
FBAnd variable reference voltage V
REF_V, produce a voltage control signal S
C
Step 310: according to voltage control signal S
C, produce an output voltage V
D, to drive illuminating source module 204.
Step 312: finish.
In addition, control unit 208 can also, by the curent change situation of direct-detection variable current source, dynamically be adjusted variable reference voltage V
REF_V, and then control electric pressure converter 202 and change out suitable output voltage V in real time
DPlease refer to Fig. 4, Fig. 4 is the schematic diagram of the embodiment of the present invention one light-emitting device 40.It should be noted that, the assembly that has same names in light-emitting device 40 due to the light-emitting device 20 of Fig. 2 and Fig. 4 has similar function mode and function, therefore for asking description for purpose of brevity, describe in detail just in this omission, the connection relationship of described assembly as shown in Figure 4, does not repeat them here.Light-emitting device 40 includes an electric pressure converter 402, an illuminating source module 404, a variable current source 406 and a control unit 408.Control unit 408 includes a voltage selector 410, a current detector 412, an arithmetic element 414, a reference voltage transducer 416, an error amplifier 418 and a switching controller 420.Wherein, be different from light-emitting device 20 parts of Fig. 2, be that current detector 412 is coupled to variable current source 406.Current detector 412 is used for detecting the situation of change of the load current that variable current source 406 produces, and with generation current, detects signal S
L, and then dynamically adjust variable reference voltage V
REF_VIn addition, please refer to Fig. 5, variable current source 406 further can comprise a variable current mirror 502 and a current drives assembly 504.Wherein variable current mirror 502 is coupled to current detector 412, is used for producing load current I
L1～I
LmCurrent drives assembly 504, be coupled to the C of light-emitting diode group of variable current mirror 502 and illuminating source module 404
1～C
m, be used for controlling load current I be provided
L1～I
LmTo this illuminating source module light-emitting diode C of group
1～C
mIn other words, control unit 408 can direct-detection variable current mirror 502 on the variation of electric current, change out suitable output voltage V to control in real time electric pressure converter 402
DIn addition, in the present embodiment, control unit 408 is directly to be coupled to variable current mirror 502, but be not limited to this, but control unit 408 is the curent change of (for example the current drives assembly 504) on other assembly of direct-detection variable current source 406 also, that is the curent change of control unit 408 on can any assembly of detection of dynamic variable current source 406, obtain load current I
L1～I
LmSituation of change.On the other hand, on circuit design, control unit 408 and variable current source 406 can be incorporated on same chip, thus, in chip internal, can realize aforesaid function mode, and more can reach in real time, prevent that transistor from producing the purpose of scintillation effect.
Function mode about light-emitting device 40, please refer to Fig. 6, and Fig. 6 is the flow chart of the embodiment of the present invention one flow process 60.Flow process 60 comprises the following step:
Step 600: start.
Step 602: the load current I that provides on variable current source 406 is provided
L1～I
LmSituation of change, to produce a current detecting signal S
L
Step 604: according to current detecting signal S
L, adjust a variable reference voltage V
REF_V
Step 606: self-luminous light source module 404, obtain a feedback voltage V
FB
Step 608: according to feedback voltage V
FBAnd variable reference voltage V
REF_V, produce a voltage control signal S
C
Step 610: according to voltage control signal S
C, produce an output voltage V
D, to drive illuminating source module 404.
Step 612: finish.
It should be noted that, above-described embodiment is only of the present invention one explanation for example, and those skilled in the art can make according to the actual requirements suitably and revise, for instance,, because reference voltage transducer 216,416 is used for providing various magnitudes of voltage according to demand, make variable reference voltage V
REF_VFor variable.Therefore, can produce in any form required various magnitudes of voltage.As shown in Figures 7 and 8, reference voltage transducer 216,416 can be realized with multiplexer 702,802 respectively, and multiplexer 702, the 802nd, according to reference voltage conversion signal S
V, the reference voltage V that cause is default
REF_1～V
REF_zA variable reference voltage V is selected in middle switching
REF_VIn addition, voltage selector 210,410 can be according to any rule in head space voltage V
HR1～V
HRmIn select feedback voltage V
FBFor instance, voltage selector 210 can be from head space voltage V
HR1～V
HRmIn, selecting minimum head space voltage is feedback voltage VFB.On the other hand, arithmetic element 214,414 can be according to load current I
L1～I
LmSituation of change, carry out logical operation and go out rational reference voltage level, for example, according to the mean change amount of quantity, current change quantity or overall current that curent change occurs, assess the reference voltage level that calculates a correspondence.Arithmetic element 214,414 can be when at least one load current changes or every a special time, and according to the curent change situation, generation current detects signal S
LIn addition, variable current source 406 can, according to a light modulation signal, change the electric current that provides to illuminating source module 404 according to system requirements, to adjust the luminosity of the light-emitting diode on illuminating source module 404.
In sum, the present invention detects the load current I of the illuminating source module of flowing through in real time by control unit
L1～I
LmSituation of change, dynamically adjust variable reference voltage V
REF_V, and then control electric pressure converter and change out suitable output voltage V in real time
DThus, when facing the situation of load current variation, can effectively avoid excuse section space voltage to be compressed into too small, make variable current source 206 that enough load currents can't be provided, and cause illuminating source module generation scintillation, also can excuse section space voltage not too high and expend too much voltage loss on variable current source 206, and reduce the global voltage conversion efficiency.
The foregoing is only preferred embodiment of the present invention, all equalizations of doing according to claim of the present invention change and modify, and all should belong to covering scope of the present invention.
Claims (38)
1. the control method that can avoid scintillation effect, be used for an illuminating source module, includes:
The flow through situation of change of a drive current of this illuminating source module of detection, to produce a current detecting signal;
, according to this current detecting signal, adjust a variable reference voltage;
, from this illuminating source module, obtain a feedback voltage;
, according to this feedback voltage and this variable reference voltage, produce a voltage control signal; And
, according to this voltage control signal, produce an output voltage, to drive this illuminating source module.
2. control method as claimed in claim 1, wherein this illuminating source module includes a plurality of light-emitting diode group, and this drive current is that flow through respectively a plurality of load current of this a plurality of light-emitting diode group forms.
3. control method as claimed in claim 2, wherein detect the situation of change of this drive current of this illuminating source module of flowing through, to produce the step of this current detecting signal, when at least one in these a plurality of load currents being detected and changing, the situation of change of the load current that at least one changes according to this, produce this current detecting signal.
4. control method as claimed in claim 2,, wherein from this illuminating source module, obtain the step of this feedback voltage, is that selecting the minimum head space voltage is this feedback voltage in a plurality of head space voltages corresponding to this a plurality of light-emitting diode group.
5. control method as claimed in claim 1, wherein this feedback voltage is by selecting in the head space voltage corresponding to this illuminating source module.
6. control method as claimed in claim 1,, wherein according to this current detecting signal, adjust the step of this variable reference voltage, is when this current detecting signal indicates this drive current to become large, heightens this variable reference voltage.
7. control method as claimed in claim 1,, wherein according to this current detecting signal, adjust the step of this variable reference voltage, is when this current detecting signal indicates this drive current to diminish, and reduces this variable reference voltage.
8. control method as claimed in claim 1,, wherein according to this current detecting signal, adjust the step of this variable reference voltage, includes:
, according to this current detecting signal, produce a reference voltage conversion signal; And
, according to this reference voltage conversion signal, produce this variable reference voltage.
9. light-emitting device includes:
One electric pressure converter, be used for converting an input voltage to an output voltage according to a voltage control signal;
One illuminating source module, be coupled to this electric pressure converter;
One variable current source, be coupled to this illuminating source module, is used to provide a drive current, to drive this illuminating source module; And
One control unit, be coupled to this illuminating source module and this electric pressure converter, uses from this illuminating source module, obtains a feedback voltage, and detect the situation of change of this drive current of this illuminating source module of flowing through, to produce a current detecting signal;
Wherein, this control unit, according to this current detecting signal, is adjusted a variable reference voltage, and, according to this feedback voltage and this variable reference voltage, is produced this voltage control signal to this electric pressure converter.
10. light-emitting device as claimed in claim 9, wherein this illuminating source module includes a plurality of light-emitting diode group, and this drive current is that flow through respectively a plurality of load current of this a plurality of light-emitting diode group forms.
11. as the light-emitting device of claim 10, wherein each the light-emitting diode group in this a plurality of light-emitting diode group comprises a plurality of light-emitting diodes that connect with the series connection form.
12. as the light-emitting device of claim 10, wherein this control unit is at least one in these a plurality of load currents being detected while changing, the situation of change of the load current that at least one changes according to this, produce this current detecting signal.
13. as the light-emitting device of claim 10, wherein this control unit is in a plurality of head space voltages corresponding to this a plurality of light-emitting diode group, selecting minimum head space voltage is this feedback voltage.
14. light-emitting device as claimed in claim 9, wherein this control unit includes:
One voltage selector, be coupled to this illuminating source module, is used for selecting this feedback voltage in a plurality of head space voltages corresponding to this illuminating source module;
One current detector, be coupled to this illuminating source module, is used for detecting the situation of change of this drive current of this illuminating source module of flowing through, to produce this current detecting signal;
One arithmetic element, be coupled to this current detector, is used for according to this current detecting signal, produces a reference voltage conversion signal;
One reference voltage transducer, be coupled to this arithmetic element, is used for producing this variable reference voltage according to this reference voltage conversion signal;
One error amplifier, be coupled to this voltage selector and this reference voltage transducer, is used for according to this feedback voltage and this variable reference voltage, produces an error voltage signal; And
One switching controller, be coupled to this error amplifier and this electric pressure converter, is used for producing this voltage control signal, to provide to electric pressure converter according to this error voltage signal.
15. as the light-emitting device of claim 14, wherein this voltage selector is in these a plurality of head space voltages, selecting minimum head space voltage is this feedback voltage.
16. as the light-emitting device of claim 14, wherein this arithmetic element is when this current detecting signal indicates this drive current to become large, heightens this variable reference voltage.
17. as the light-emitting device of claim 14, wherein this arithmetic element is when this current detecting signal indicates this drive current to diminish, and reduces this variable reference voltage.
18. the control method that can avoid scintillation effect, be used for an illuminating source module, includes:
Detect the situation of change of a drive current that provides on a variable current source, to produce a current detecting signal;
, according to this current detecting signal, adjust a variable reference voltage;
, from this illuminating source module, obtain a feedback voltage;
, according to this feedback voltage and this variable reference voltage, produce a voltage control signal; And
, according to this voltage control signal, produce an output voltage, to drive this illuminating source module.
19. as the control method of claim 18, wherein this illuminating source module includes a plurality of light-emitting diode group, and this drive current comprises a plurality of load currents that are used to provide respectively this a plurality of light-emitting diode group.
20. the control method as claim 19, the situation of change of this drive current that provides on this variable current source wherein is provided, to produce the step of this current detecting signal, when at least one in these a plurality of load currents being detected and changing, the situation of change of the load current that at least one changes according to this, produce this current detecting signal.
, 21., as the control method of claim 19,, wherein from this illuminating source module, obtain the step of this feedback voltage, be that selecting the minimum head space voltage is this feedback voltage in a plurality of head space voltages corresponding to this a plurality of light-emitting diode group.
22. as the control method of claim 18, wherein this feedback voltage is by selecting in the head space voltage corresponding to this illuminating source module.
23., as the control method of claim 18,, wherein according to this current detecting signal, adjust the step of this variable reference voltage, be when this current detecting signal indicates this drive current to become large, heighten this variable reference voltage.
24., as the control method of claim 18,, wherein according to this current detecting signal, adjust the step of this variable reference voltage, be when this current detecting signal indicates this drive current to diminish, reduce this variable reference voltage.
25., as the control method of claim 18,, wherein according to this current detecting signal, adjust the step of this variable reference voltage, include:
, according to this current detecting signal, produce a reference voltage conversion signal; And
, according to this reference voltage conversion signal, produce this variable reference voltage.
26. a light-emitting device includes:
One electric pressure converter, be used for converting an input voltage to an output voltage according to a voltage control signal;
One illuminating source module, be coupled to this electric pressure converter;
One variable current source, be coupled to this illuminating source module, is used for producing a drive current, to drive this illuminating source module; And
One control unit, be coupled to this variable current source and this electric pressure converter, uses from this illuminating source module, obtains a feedback voltage, and the situation of change of this drive current that provides on this variable current source is provided, to produce a current detecting signal;
Wherein, this control unit, according to this current detecting signal, is adjusted a variable reference voltage, and, according to this feedback voltage and this variable reference voltage, is produced this voltage control signal to this electric pressure converter.
27. as the light-emitting device of claim 26, wherein this illuminating source module includes a plurality of light-emitting diode group, and this drive current is that flow through respectively a plurality of load current of this a plurality of light-emitting diode group forms.
28. as the light-emitting device of claim 27, wherein each the light-emitting diode group in this a plurality of light-emitting diode group comprises a plurality of light-emitting diodes that connect with the series connection form.
29. as the light-emitting device of claim 27, wherein this control unit is at least one in these a plurality of load currents being detected while changing, the situation of change of the load current that at least one changes according to this, produce this current detecting signal.
30. as the light-emitting device of claim 27, wherein this control unit is in a plurality of head space voltages corresponding to this a plurality of light-emitting diode group, selecting minimum head space voltage is this feedback voltage.
31. as the light-emitting device of claim 26, wherein this variable current source can, according to the demand of this illuminating source module, produce this drive current.
32. as the light-emitting device of claim 26, wherein this variable current source can, according to a light modulation signal, produce this drive current.
33. as the light-emitting device of claim 26, wherein this variable current source includes:
One variable current mirror, be coupled to this control unit, is used for producing this drive current; And
One current drives assembly, be coupled to this variable current mirror and this illuminating source module, and being used for controlling provides this drive current to this illuminating source module.
34. as the light-emitting device of claim 33, wherein this control unit can detect the situation of change of the electric current that this variable current mirror provides, to produce this current detecting signal.
35. as the light-emitting device of claim 26, wherein this control unit includes:
One voltage selector, be coupled to this illuminating source module, is used for selecting this feedback voltage in a plurality of head space voltages corresponding to this illuminating source module;
One current detector, be coupled to this variable current source, is used for detecting the situation of change of this drive current that this variable current source produces, to produce this current detecting signal;
One arithmetic element, be coupled to this current detector, is used for according to this current detecting signal, produces a reference voltage conversion signal;
One reference voltage transducer, be coupled to this arithmetic element, is used for producing this variable reference voltage according to this reference voltage conversion signal;
One error amplifier, be coupled to this voltage selector and this reference voltage transducer, is used for according to this feedback voltage and this variable reference voltage, produces an error voltage signal; And
One switching controller, be coupled to this error amplifier and this electric pressure converter, is used for producing this voltage control signal, to provide to electric pressure converter according to this error voltage signal.
36. as the light-emitting device of claim 35, wherein this voltage selector is in these a plurality of head space voltages, selecting minimum head space voltage is this feedback voltage.
37. as the light-emitting device of claim 35, wherein this arithmetic element is when this current detecting signal indicates this drive current to become large, heightens this variable reference voltage.
38. as the light-emitting device of claim 35, wherein this arithmetic element is when this current detecting signal indicates this drive current to diminish, and reduces this variable reference voltage.
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| CN2009101706355A CN102006698B (en) | 2009-09-01 | 2009-09-01 | Control method for avoiding flicker effect and illumination device |
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| CN2009101706355A CN102006698B (en) | 2009-09-01 | 2009-09-01 | Control method for avoiding flicker effect and illumination device |
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| CN102006698B true CN102006698B (en) | 2013-11-20 |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN102843807B (en) * | 2011-06-21 | 2014-09-10 | 原景科技股份有限公司 | LED circuit with LED drive circuit |
| CN102244964B (en) * | 2011-07-07 | 2013-09-25 | 矽力杰半导体技术(杭州)有限公司 | Hybrid multi-output power supply and regulating method thereof |
| JP6160955B2 (en) | 2013-07-10 | 2017-07-12 | パナソニックＩｐマネジメント株式会社 | LIGHT EMITTING DIODE DRIVING DEVICE, VEHICLE LIGHTING DEVICE HAVING THE SAME, AND VEHICLE |
| CN109032232B (en) * | 2015-12-28 | 2020-04-28 | 台达电子企业管理（上海）有限公司 | Electronic device |
| CN111198470B (en) * | 2018-10-30 | 2022-03-18 | 中强光电股份有限公司 | Projection system, driving device and driving method |
| CN113556848A (en) * | 2020-04-24 | 2021-10-26 | 中强光电股份有限公司 | Light emitting device and light generating method |
| CN114399978B (en) * | 2022-03-24 | 2022-07-01 | 南京浣轩半导体有限公司 | Control method and system for dynamic energy saving of LED backlight |
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