CN101778503B - Light source device and light source drive circuit thereof - Google Patents
Light source device and light source drive circuit thereof Download PDFInfo
- Publication number
- CN101778503B CN101778503B CN2009100016564A CN200910001656A CN101778503B CN 101778503 B CN101778503 B CN 101778503B CN 2009100016564 A CN2009100016564 A CN 2009100016564A CN 200910001656 A CN200910001656 A CN 200910001656A CN 101778503 B CN101778503 B CN 101778503B
- Authority
- CN
- China
- Prior art keywords
- voltage
- switch
- light source
- operational amplifier
- couples
- 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.)
- Expired - Fee Related
Links
Images
Landscapes
- Control Of Indicators Other Than Cathode Ray Tubes (AREA)
Abstract
The invention relates to a light source device and a light source drive circuit thereof. The light source drive circuit comprises an operational amplifier, a transistor and a switching unit. The first input end of the operational amplifier is coupled to a preset voltage. The first end of the transistor is coupled to a light source, and the control end thereof is coupled to the output end of the operational amplifier. The first signal end of the switching unit receives a first voltage larger than the preset voltage, the second signal end thereof is coupled to the second input end of the operational amplifier, the third signal end thereof is coupled to the second end of the transistor, and the enabling end thereof receives a drive voltage. When the drive voltage is enabled, the voltage of the third signal end is transferred to the second signal end. When the drive voltage is disabled, the voltage of the first signal end is transferred to the second signal end.
Description
Technical field
The invention relates to a kind of driving circuit, and particularly relevant for a kind of increase and the identical light supply apparatus and light source driving circuit thereof of minimizing speed that can make the drive current of light source.
Background technology
In recent years, because the continuous breakthrough of photoelectric technology, (light emitting diode LED) is widely used to make the light emitting diode that possesses the cheap and simple operation and other advantages of cost.Wherein, monochromatic application has traffic sign, hand-held illumination and meter lamp etc., and colored application then has advertisement billboard and ultra-large type display etc.
With display, when generally the driving circuit of light emitting diode is for switched drive current, usually need changes the input reference voltage of operational amplifier or close operational amplifier, and cause the significantly change of inside chip operating current.
Fig. 1 is the circuit diagram of known light supply apparatus.Please with reference to Fig. 1, in light supply apparatus 100, light emitting diode serial D1～Dn is coupled between the drain electrode of system voltage Vdd and transistor M1, and electric current I then is light emitting diode serial D
1～D
nDrive current.According to the electrical specification of operational amplifier 101 (that is; When having only an end input voltage; The voltage of positive input terminal can equate with the voltage of negative input end), the current value of drive current I is Vin/R (that is the magnitude of voltage of driving voltage Vin is divided by resistance value of resistance R).Therefore, the size of drive current I can be determined that the voltage that also can see through adjustment driving voltage Vin comes switched drive current I by the voltage of driving voltage Vin.In addition, close drive current I, also can be by closing operational amplifier 101, be reduced to low voltage level with voltage and then can the gate terminal of transistor M1.And the mode of operation of above-mentioned switch all can cause the inside chip operating current significantly to change.And, come switched drive current I with the voltage that sees through adjustment driving voltage Vin, the Control of Voltage of previous stage (that is light source controller 102) must be very accurate, and if not, the increase of drive current I and the speed of minimizing can be different.
Summary of the invention
The present invention provides a kind of light supply apparatus, can reduce the amplitude of fluctuation of the operating current of inside chip.
The present invention provides a kind of light source driving circuit in addition, can make the increase and the minimizing speed of drive current of light source identical.
The present invention provides a kind of light source driving circuit, and it comprises operational amplifier, transistor, switch unit and first resistance.Operational amplifier has first input end, second input end and output terminal, and its first end couples predeterminated voltage.Transistor has first end, second end and control end, and its first end couples light source, and control end couples the output terminal of operational amplifier.Switch unit has first signal end, secondary signal end, the 3rd signal end and activation end; Its first signal end receives first voltage greater than predeterminated voltage; Its secondary signal end couples second input end of operational amplifier; Its 3rd signal end couples transistorized second end, and its activation termination is received a driving voltage.When driving voltage was activation, switch unit passed to the secondary signal end with the voltage of the 3rd signal end.When driving voltage was anergy, switch unit passed to the secondary signal end with the voltage of first signal end.First resistance is coupled between transistorized second end and second voltage.
The present invention provides a kind of light supply apparatus in addition, and it comprises light source driving circuit.First end of light source couples tertiary voltage.Light source driving circuit comprises operational amplifier, transistor, switch unit and first resistance.Operational amplifier has first input end, second input end and output terminal, and its first end couples predeterminated voltage.Transistor has first end, second end and control end, and its first end couples second end of light source, and control end couples the output terminal of operational amplifier.Switch unit has first signal end, secondary signal end, the 3rd signal end and activation end; Its first signal end receives first voltage greater than predeterminated voltage; Its secondary signal end couples second input end of operational amplifier; Its 3rd signal end couples transistorized second end, and its activation termination is received a driving voltage.When driving voltage was activation, switch unit passed to the secondary signal end with the voltage of the 3rd signal end.When driving voltage was anergy, switch unit passed to the secondary signal end with the voltage of first signal end.First resistance is coupled between transistorized second end and second voltage.
Based on above-mentioned, light supply apparatus of the present invention and light source driving circuit thereof carry out the switching that voltage transmits between signal end by switch unit according to driving voltage, make the circuit operational function of operational amplifier to switch at comparer and voltage follower.And, when operational amplifier is treated as comparer, make the voltage of its output present not conducting by transistor; When operational amplifier is treated as voltage follower, let transistor present conducting with driving light source.By this, can reduce the amplitude of fluctuation of the operating current of inside chip, simultaneously because the electrical specification of operational amplifier is stable, so the increase of the drive current of light source and minimizing speed can be identical.
For letting the above-mentioned feature and advantage of the present invention can be more obviously understandable, hereinafter is special lifts embodiment, and cooperates appended graphic elaborating as follows.
Description of drawings
Fig. 1 is the circuit diagram of known light supply apparatus.
Fig. 2 is the circuit diagram according to the light supply apparatus of first embodiment of the invention.
Fig. 3 is the circuit diagram according to the light supply apparatus of second embodiment of the invention.
Fig. 4 is the circuit diagram according to the light supply apparatus of third embodiment of the invention.
Fig. 5 is the circuit diagram according to the light supply apparatus of fourth embodiment of the invention.
Fig. 6 is the circuit diagram according to the light supply apparatus of fifth embodiment of the invention.
Fig. 7 is the circuit diagram according to the light supply apparatus of sixth embodiment of the invention.
[primary clustering symbol description]
100,200,300,400,500,600,700: light supply apparatus
101,211: operational amplifier
210,310,410,510,610,710: driving circuit
212,311,411,511,611,711: switch unit
220: light source
D
1～D
n, L
1～L
n: light emitting diode
M1, N1, P1: transistor
S1, S2: switch
R, R1, R2: resistance
I, I
1, I
2: electric current
Vdd, Vcc: system voltage
V1: first voltage
Vpre: predeterminated voltage
Vin, VDR: driving voltage
Embodiment
[first embodiment]
Fig. 2 is the circuit diagram according to the light supply apparatus of first embodiment of the invention.Please with reference to Fig. 2, in the present embodiment, light supply apparatus 200 comprises driving circuit 210, light source 220 and light source controller 230, wherein light source 220 at this with light emitting diode serial L
1～L
nBe example.Light source 220 is coupled between system voltage Vcc (that is tertiary voltage) and the driving circuit 210.Driving circuit 210 couples light source controller 230 to receive driving voltage V
DR, driving circuit 210 comprises operational amplifier 211, switch unit 212, transistor N1, first resistance R 1, wherein transistor N1 is example with the nmos pass transistor at this.And switch unit 212 comprises first switch S 1 and second switch S2.
The positive input terminal of operational amplifier 211 (that is first input end) receives predeterminated voltage Vpre, and its negative input end (that is second input end) couples second end of first switch S 1, and its output terminal couples the gate terminal (that is control end) of transistor N1.First end of first switch S 1 couples the first voltage V1, and wherein the first voltage V1 is greater than predeterminated voltage Vpre, and the first voltage V1 and predeterminated voltage Vpre are all fixed value.First end of second switch S2 couples second end of first switch S 1, and second end of second switch S2 couples the source terminal (that is second end) of transistor N1.The drain electrode end of transistor N1 (that is first end) couples light source 210.First resistance R 1 is coupled between the source terminal and ground voltage (that is second voltage) of transistor N1.
In the present embodiment, switch S 1 and S2 all can be according to driving voltage V
DRAnd move.As driving voltage V
DRDuring for activation (for example being logic high voltage level), switch S 1 is not conducting, and switch S 2 is conducting.This moment, operational amplifier 211 operated according to circuit, can be considered voltage follower.And the voltage of the gate terminal of transistor N1 can be drawn high by the voltage of operational amplifier 211 output terminals, makes transistor N1 present conducting, after the circuit running, makes the pressure drop meeting of resistance R 1 equal the magnitude of voltage of predeterminated voltage Vpre, and is delivered to negative input end.Simultaneously, because transistor N1 presents conducting, so driving circuit 210 can provide drive current I
1Give light source 220.And drive current I
1Can the rough resistance value that equals the magnitude of voltage of predeterminated voltage Vpre divided by resistance R 1.
As driving voltage V
DRDuring for anergy (for example being the accurate position of logic low-voltage), switch S 1 is conducting, and switch S 2 is not conducting, makes the voltage V1 that wins be delivered to negative input end.Operational amplifier 211 can be considered comparer according to its circuit running at this moment.Because the first voltage V1 is greater than predeterminated voltage Vpre; That is the voltage of negative input end is higher than the voltage of positive input terminal; That is owing to the excessive loop state that forms out of the positive-negative input end pressure reduction of operational amplifier 211, and the Negative Pressure Difference that positive-negative input end causes (that is the voltage of negative input end is higher than the voltage of positive input terminal) can be exaggerated, so the output terminal of operational amplifier 211 meeting output LOW voltage level (for example being ground voltage); Make transistor N1 present not conducting, to close drive current I
1
With the control technology of light-source brightness, can adjust the brightness of light source 220 through the technology of pulse-length modulation, that is can pass through driving voltage V
DRPulse width modulate the i.e. brightness of may command light source 220 (that is drive current I
1Size).Because above-mentioned control mode is to utilize the circuit of operational amplifier 211 to operate to realize; Because operational amplifier 211 revolution rate of its output when opening the loop is relevant with the tail current (tail) of operational amplifier 211 input ends own; Therefore no matter be to increase or to reduce its revolution rate also identical, so drive current I
1Increase or minimizing speed all be identical.And, the driving voltage V of aforesaid way
DRThe requirement of voltage level can be lower than knownly, that is the employed chip level of its prime (that is light source controller 230) can be lower, can reduce the cost that its prime makes up by this.
[second embodiment]
Fig. 3 is the circuit diagram according to the light supply apparatus of second embodiment of the invention.Please with reference to Fig. 2 and Fig. 3, its maximum difference is the switch unit 311 of driving circuit 310.In switch unit 312, it utilizes one second resistance R 2 to replace switch S 2, the resistance value when wherein the resistance value of first resistance R 2 can be greater than switch S 1 conducting.As driving voltage V
DRDuring for activation, switch S 1 is not conducting.This moment, operational amplifier 211 made the pressure drop meeting of resistance R 1 equal the magnitude of voltage of predeterminated voltage Vpre after the circuit running, and because the electric current of negative input end is almost nil, so the pressure drop of resistance R 2 also almost nil (that is resistance R 2 can be considered short circuit).Therefore, the pressure drop on the resistance R 1 (approximating predeterminated voltage Vpre) can be delivered to the negative input end of operational amplifier 211, makes that the circuit running of operational amplifier 211 is general as voltage follower.
And the voltage of the gate terminal of transistor N1 can be drawn high by the voltage of operational amplifier 211 output terminals, makes transistor N1 present conducting, so that drive current I to be provided
1Give light source 220.And drive current I
1Can the rough resistance value that equals the magnitude of voltage of predeterminated voltage Vpre divided by resistance R 1.As driving voltage V
DRDuring for anergy, switch S 1 is conducting.And the resistance value of resistance R 2 is because the resistance value during much larger than switch S 1 conducting so the conducting of switch S 1 can not cause pressure drop, makes the voltage V1 that wins can be delivered to negative input end (that is resistance R 2 can be treated as open circuit).The voltage of the negative input end of operational amplifier 211 can approximate the first voltage V1 at this moment; Make operational amplifier 211 form and open loop state; Negative Pressure Difference between same positive-negative input end can be exaggerated; So the output terminal of operational amplifier 211 meeting output LOW voltage level makes transistor N1 present not conducting, to close drive current I
1
[the 3rd embodiment]
Fig. 4 is the circuit diagram according to the light supply apparatus of third embodiment of the invention.Please with reference to Fig. 2 and Fig. 4, its maximum difference is the switch unit 411 of driving circuit 410.In switch unit 411, it utilizes one second resistance R 2 to replace switch S 1, the resistance value when wherein the resistance value of first resistance R 2 can be greater than switch S 2 conductings.As driving voltage V
DRDuring for activation, switch S 2 is conducting.This moment, operational amplifier 211 made the pressure drop meeting of resistance R 1 equal the magnitude of voltage of predeterminated voltage Vpre after the circuit running, that is the voltage of negative input end can equal the magnitude of voltage of predeterminated voltage Vpre.And, the resistance value of the resistance value of resistance R 2 during much larger than switch S 2 conductings, and the pressure reduction of voltage V1 and predeterminated voltage Vpre can be absorbed (that is resistance R 2 can be considered open circuit) by resistance R 2, cause the circuit of operational amplifier 211 to operate general as voltage follower.And drive current I
1Can the rough resistance value that equals the magnitude of voltage of predeterminated voltage Vpre divided by resistance R 1.
As driving voltage V
DRDuring for anergy, switch S 2 is not conducting.At this moment, because negative input end can not produce electric current,, make the voltage V1 that wins to be delivered to the negative input end of operational amplifier 211 so resistance R 2 can not produce pressure drop (that is resistance R 2 can be considered short circuit).And this moment operational amplifier 211 the running meeting the same with comparer, and the voltage of negative input end is higher than positive input terminal, so the output terminal of operational amplifier 211 can the output LOW voltage level, makes transistor N1 present not conducting, to close drive current I
1
[the 4th embodiment]
Fig. 5 is the circuit diagram according to the light supply apparatus of fourth embodiment of the invention.Please with reference to Fig. 5, in the present embodiment, light supply apparatus 500 comprises driving circuit 510, light source 520 and light source controller 230, wherein uses similar label with the assembly of the first embodiment identity function.Light source 520 is coupled between ground voltage (that is tertiary voltage) and the driving circuit 510, and light source 520 is equally with light emitting diode serial L
1～L
nBe example.Driving circuit 510 couples light source controller 230 to receive driving voltage V
DR, driving circuit 510 comprises operational amplifier 211, switch unit 511, transistor P1, resistance R 1, wherein transistor P1 is example at this with the PMOS transistor.And switch unit 511 comprises switch S 1 and S2.
The negative input end of operational amplifier 211 (that is first input end) receives predeterminated voltage Vpre, and its positive input terminal (that is second input end) couples second end of switch S 1, and its output terminal couples the gate terminal (that is control end) of transistor P1.First end of switch S 1 couples the first voltage V1.First end of switch S 2 couples second end of switch S 1, and second end of switch S 2 couples the source terminal (that is second end) of transistor P1.The drain electrode end of transistor P1 (that is first end) couples light source 210.Resistance R 1 is coupled between the source terminal and system voltage Vcc (that is second voltage) of transistor N1.
And the function mode of switch unit 511 can be similar with the switch unit 211 of Fig. 2 embodiment, so do not give unnecessary details at this.As driving voltage V
DRDuring for activation, transistor P1 meeting conducting is to provide drive current I
2Give light source 520, wherein drive current I
2Can the rough voltage that equals system voltage Vcc deduct predeterminated voltage Vpre again divided by the resistance value of resistance R 1.As driving voltage V
DRDuring for anergy, because the positive-negative input end of 211 of operational amplifiers can present positive pressure differential (that is the voltage of positive input terminal is greater than voltage of negative input end), making can output HIGH voltage level (for example being system voltage Vcc) in operational amplifier 211 output terminals.Therefore, transistor P1 can present not conducting, and closes drive current I
2
[the 5th embodiment]
Fig. 6 is the circuit diagram according to the light supply apparatus of fifth embodiment of the invention.Please with reference to Fig. 5 and Fig. 6, its maximum difference is in the switch unit 611 of driving circuit 610.In switch unit 611, it utilizes one second resistance R 2 replacement switch S 2.And the function mode of switch unit 611 can be similar with the switch unit 311 of Fig. 3 embodiment, so do not give unnecessary details at this.As driving voltage V
DRDuring for activation, transistor P1 meeting conducting is to provide drive current I
2Give light source 520, wherein drive current I
2The magnitude of voltage that can the rough magnitude of voltage that equals system voltage Vcc deducts predeterminated voltage Vpre is again divided by the resistance value of resistance R 1.As driving voltage V
DRDuring for anergy, because the positive-negative input end of 211 of operational amplifiers can present positive pressure differential, making can the output HIGH voltage level in operational amplifier 211 output terminals.Therefore, transistor P1 can present not conducting, and closes drive current I
2
[the 6th embodiment]
Fig. 7 is the circuit diagram according to the light supply apparatus of sixth embodiment of the invention.Please with reference to Fig. 5 and Fig. 7, its maximum difference is in the switch unit 711 of driving circuit 710.In switch unit 711, it utilizes one second resistance R 2 replacement switch S 1.And the function mode of switch unit 711 can be identical with the switch unit 411 of Fig. 4 embodiment, so do not give unnecessary details at this.As driving voltage V
DRDuring for activation, transistor P1 meeting conducting is to provide drive current I
2Give light source 520, wherein drive current I
2The magnitude of voltage that can the rough magnitude of voltage that equals system voltage Vcc deducts predeterminated voltage Vpre is again divided by the resistance value of resistance R 1.As driving voltage V
DRDuring for anergy, because the positive-negative input end of 211 of operational amplifiers can present positive pressure differential, making can the output HIGH voltage level in operational amplifier 211 output terminals.Therefore, transistor P1 can present not conducting, and closes drive current I
2
What deserves to be mentioned is; Transistor N1 among above-mentioned first, second and third embodiment can substitute by the NPN junction transistor; Its base stage couples the output terminal of operational amplifier; Its collector couples light source, with and emitter couple resistance and switch unit, can realize the circuit running of first, second and third embodiment equally.And; Transistor P1 among above-mentioned the 4th, the 5th and the 6th embodiment can substitute by the positive-negative-positive transistor npn npn; Its base stage couples the output terminal of operational amplifier; Its collector couples light source, with and emitter couple resistance and switch unit, can realize the circuit running of the 4th, the 5th and the 6th embodiment equally.
In sum, light supply apparatus and the light source driving circuit thereof of all embodiment of the present invention carry out the switching that voltage transmits between signal end by switch unit according to driving voltage, make the operational function of operational amplifier to switch at comparer and voltage follower.And, when operational amplifier is treated as comparer, make the voltage of its output present not conducting by transistor; When operational amplifier is treated as voltage follower, let transistor present conducting with driving light source.By this, can reduce the amplitude of fluctuation of the operating current of inside chip, simultaneously because the electrical specification of operational amplifier is stable, so the increase of the drive current of light source and minimizing speed can be identical.
Though the present invention with embodiment openly as above; Right its is not in order to limit the present invention; Has common knowledge the knowledgeable in the technical field under any; Do not breaking away from the spirit and scope of the present invention, when doing a little change and retouching, so protection scope of the present invention is as the criterion when looking the accompanying Claim book person of defining.
Claims (34)
1. light source driving circuit comprises:
One operational amplifier has a first input end, one second input end and an output terminal, and this first input end couples a predeterminated voltage;
One transistor has one first end, one second end and a control end, and this first end couples a light source, and this control end couples the output terminal of this operational amplifier;
One switching unit; Have one first signal end, a secondary signal end, one the 3rd signal end and an activation end, this first signal end receives one first voltage greater than this predeterminated voltage, and this secondary signal end couples second input end of this operational amplifier; The 3rd signal end couples this transistorized second end; This activation termination is received a driving voltage, and wherein when this driving voltage was activation, this switch unit passed to this secondary signal end with the voltage of the 3rd signal end; And when this driving voltage was anergy, this switch unit passed to this secondary signal end with the voltage of this first signal end; And
One first resistance is coupled between this transistorized second end and one second voltage.
2. light source driving circuit as claimed in claim 1, wherein this switch unit comprises:
One first switch; Have one first end and one second end, first termination of this first switch is received this first voltage, and second end of this first switch couples second input end of this operational amplifier; Wherein when this driving voltage is activation; This first switch is not conducting, and when this driving voltage was anergy, this first switch was conducting; And
One second switch; Have one first end and one second end, first end of this second switch couples second input end of this operational amplifier, and second end of this second switch couples this transistorized second end; Wherein when this driving voltage is activation; This second switch is conducting, and when this driving voltage was anergy, this second switch was not conducting.
3. light source driving circuit as claimed in claim 1, wherein this switch unit comprises:
One first switch; Have one first end and one second end, first end of this first switch couples this first voltage, and second end of this first switch couples second input end of this operational amplifier; Wherein when this driving voltage is activation; This first switch is not conducting, and when this driving voltage was anergy, this first switch was conducting; And
One second resistance is coupled between second input end and this transistorized second end of this operational amplifier.
4. light source driving circuit as claimed in claim 1, wherein this switch unit comprises:
One second resistance is coupled between second input end of this first voltage and this operational amplifier;
One second switch; Have one first end and one second end, first end of this second switch couples second input end of this operational amplifier, and second end of this second switch couples this transistorized second end; Wherein when this driving voltage is activation; This second switch is conducting, and when this driving voltage was anergy, this second switch was not conducting.
5. light source driving circuit as claimed in claim 1, wherein the first input end of this operational amplifier and second input end are respectively a positive input terminal and a negative input end.
6. light source driving circuit as claimed in claim 1, wherein this second voltage is a ground voltage.
7. light source driving circuit as claimed in claim 6, wherein this transistor is a nmos pass transistor.
8. light source driving circuit as claimed in claim 7, wherein this transistorized first end is a drain electrode end, and this second end is the one source pole end, and this control end is a gate terminal.
9. light source driving circuit as claimed in claim 6, wherein this transistor is a NPN junction transistor.
10. light source driving circuit as claimed in claim 9, wherein this transistorized first end is a collector terminal, and this second end is an emitter terminal, and this control end is a base terminal.
11. light source driving circuit as claimed in claim 1, wherein this second voltage is a system voltage.
12. light source driving circuit as claimed in claim 11, wherein this transistor is a PMOS transistor.
13. light source driving circuit as claimed in claim 12, wherein this transistorized first end is a drain electrode end, and this second end is the one source pole end, and this control end is a gate terminal.
14. light source driving circuit as claimed in claim 11, wherein this transistor is a positive-negative-positive transistor npn npn.
15. light source driving circuit as claimed in claim 14, wherein this transistorized first end is a collector terminal, and this second end is an emitter terminal, and this control end is a base terminal.
16. light source driving circuit as claimed in claim 1, wherein this predeterminated voltage is a fixed voltage.
17. a light supply apparatus comprises:
One light source, its first end couples a tertiary voltage; And
One light source driving circuit comprises:
One operational amplifier has a first input end, one second input end and an output terminal, and this first end couples a predeterminated voltage;
One transistor has one first end, one second end and a control end, and this first end couples second end of this light source, and this control end couples the output terminal of this operational amplifier;
One switching unit; Have one first signal end, a secondary signal end, one the 3rd signal end and an activation end, this first signal end receives one first voltage greater than this predeterminated voltage, and this secondary signal end couples second input end of this operational amplifier; The 3rd signal end couples this transistorized second end; This activation termination is received a driving voltage, and wherein when this driving voltage was activation, this switch unit passed to this secondary signal end with the voltage of the 3rd signal end; And when this driving voltage was anergy, this switch unit passed to this secondary signal end with the voltage of this first signal end; And
One first resistance is coupled between this transistorized second end and one second voltage.
18. light supply apparatus as claimed in claim 17, wherein this switch unit comprises:
One first switch; Have one first end and one second end, first termination of this first switch is received this first voltage, and second end of this first switch couples second input end of this operational amplifier; Wherein when this driving voltage is activation; This first switch is not conducting, and when this driving voltage was anergy, this first switch was conducting; And
One second switch; Have one first end and one second end, first end of this second switch couples second input end of this operational amplifier, and second end of this second switch couples this transistorized second end; Wherein when this driving voltage is activation; This second switch is conducting, and when this driving voltage was anergy, this second switch was not conducting.
19. light supply apparatus as claimed in claim 17, wherein this switch unit comprises:
One first switch; Have one first end and one second end, first end of this first switch couples this first voltage, and second end of this first switch couples second input end of this operational amplifier; Wherein when this driving voltage is activation; This first switch is not conducting, and when this driving voltage was anergy, this first switch was conducting; And
One second resistance is coupled between second input end and this transistorized second end of this operational amplifier.
20. light supply apparatus as claimed in claim 17, wherein this switch unit comprises:
One second resistance is coupled between second input end of this first voltage and this operational amplifier;
One second switch; Have one first end and one second end, first end of this second switch couples second input end of this operational amplifier, and second end of this second switch couples this transistorized second end; Wherein when this driving voltage is activation; This second switch is conducting, and when this driving voltage was anergy, this second switch was not conducting.
21. light supply apparatus as claimed in claim 17, wherein the first input end of this operational amplifier and second input end are respectively a positive input terminal and a negative input end.
22. light supply apparatus as claimed in claim 17, wherein this second voltage is a ground voltage.
23. light supply apparatus as claimed in claim 22, wherein this transistor is a nmos pass transistor.
24. light supply apparatus as claimed in claim 23, wherein this transistorized first end is a drain electrode end, and this second end is the one source pole end, and this control end is a gate terminal.
25. light supply apparatus as claimed in claim 22, wherein this transistor is a NPN junction transistor.
26. light supply apparatus as claimed in claim 24, wherein this transistorized first end is a collector terminal, and this second end is an emitter terminal, and this control end is a base terminal.
27. light supply apparatus as claimed in claim 17, wherein this second voltage is a system voltage.
28. light supply apparatus as claimed in claim 27, wherein this transistor is a PMOS transistor.
29. light supply apparatus as claimed in claim 28, wherein this transistorized first end is a drain electrode end, and this second end is the one source pole end, and this control end is a gate terminal.
30. light supply apparatus as claimed in claim 27, wherein this transistor is a positive-negative-positive transistor npn npn.
31. light supply apparatus as claimed in claim 30, wherein this transistorized first end is a collector terminal, and this second end is an emitter terminal, and this control end is a base terminal.
32. light supply apparatus as claimed in claim 17, wherein this light source comprises at least one light emitting diode.
33. light supply apparatus as claimed in claim 17, wherein this predeterminated voltage is a fixed voltage.
34. light supply apparatus as claimed in claim 17, wherein this tertiary voltage is a ground voltage or a system voltage.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2009100016564A CN101778503B (en) | 2009-01-09 | 2009-01-09 | Light source device and light source drive circuit thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2009100016564A CN101778503B (en) | 2009-01-09 | 2009-01-09 | Light source device and light source drive circuit thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN101778503A CN101778503A (en) | 2010-07-14 |
| CN101778503B true CN101778503B (en) | 2012-11-28 |
Family
ID=42514767
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2009100016564A Expired - Fee Related CN101778503B (en) | 2009-01-09 | 2009-01-09 | Light source device and light source drive circuit thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN101778503B (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8629632B2 (en) * | 2010-11-11 | 2014-01-14 | Maxim Integrated Products, Inc. | LED backlight driver |
| CN110320733B (en) * | 2018-03-30 | 2021-10-15 | 中强光电股份有限公司 | Projection system, light beam generating device thereof and light beam generating method |
| CN117813645A (en) * | 2022-07-29 | 2024-04-02 | 京东方科技集团股份有限公司 | Driving circuit, backlight module, driving method of backlight module and display device |
| CN117033265B (en) * | 2023-10-10 | 2024-04-02 | 荣耀终端有限公司 | Signal transmission circuit, control method thereof and electronic equipment |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101106855A (en) * | 2007-07-20 | 2008-01-16 | 北京中星微电子有限公司 | LED drive circuit |
| CN101290743A (en) * | 2007-01-09 | 2008-10-22 | 奇景光电股份有限公司 | Active type matrix organic led circuit drive circuit possessing gamma correction |
| CN101330203A (en) * | 2008-07-30 | 2008-12-24 | 电子科技大学 | Current deep constant-current output driving circuit with load short circuit protection function |
-
2009
- 2009-01-09 CN CN2009100016564A patent/CN101778503B/en not_active Expired - Fee Related
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101290743A (en) * | 2007-01-09 | 2008-10-22 | 奇景光电股份有限公司 | Active type matrix organic led circuit drive circuit possessing gamma correction |
| CN101106855A (en) * | 2007-07-20 | 2008-01-16 | 北京中星微电子有限公司 | LED drive circuit |
| CN101330203A (en) * | 2008-07-30 | 2008-12-24 | 电子科技大学 | Current deep constant-current output driving circuit with load short circuit protection function |
Also Published As
| Publication number | Publication date |
|---|---|
| CN101778503A (en) | 2010-07-14 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP4067803B2 (en) | Light emitting diode driving circuit and optical transmission device using the same | |
| CN104682190B (en) | Laser diode drive | |
| CN101557669B (en) | High precision controllable current source | |
| US7622871B2 (en) | Light emitting diode driver circuit with shunt switch | |
| US9185763B2 (en) | Light emitting diode string driving method | |
| CN102088808B (en) | Contact current LED driving circuit of snap switch | |
| CN101778503B (en) | Light source device and light source drive circuit thereof | |
| CN101795515B (en) | Started overshoot current suppression circuit | |
| CN102708802B (en) | Light emitting diode (LED) display system | |
| CN108320700A (en) | Micro light emitting diode display panel and driving method | |
| TWI594664B (en) | Light-emitting diode driving device and short protection method for driving device | |
| CN102256418A (en) | PWM (pulse width modulation) dimming circuit | |
| CN102157901B (en) | Light emitting element driving circuit | |
| CN110136639B (en) | Driving circuit | |
| CN109257852B (en) | LED control circuit | |
| CN103646635B (en) | Level shifter and booster driving circuit | |
| CN102654989B (en) | Backlight module drive method and system of liquid crystal display | |
| CN110033731A (en) | Combined type drives display panel | |
| CN106211474B (en) | A kind of light adjusting circuit and display device of a variety of dimming modes of compatibility | |
| CN214125579U (en) | LED amplifying unit and dimming drive circuit comprising same | |
| CN105407614B (en) | A kind of adjusting control circuit provided with fan and turn-off function | |
| CN208479984U (en) | The parallel connection LED flow equalizing circuit of motor-driven system | |
| US8237369B2 (en) | Light source apparatus and driving circuit thereof | |
| CN111867185A (en) | Capacitor pre-charging circuit, LED drive circuit and LED device | |
| CN217160059U (en) | Color temperature switching circuit of LED power supply and LED power supply |
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 | ||
| CF01 | Termination of patent right due to non-payment of annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20121128 Termination date: 20210109 |