CN103796373A - Light-emitting diode illumination system with clamping device - Google Patents
Light-emitting diode illumination system with clamping device Download PDFInfo
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- CN103796373A CN103796373A CN201210434428.8A CN201210434428A CN103796373A CN 103796373 A CN103796373 A CN 103796373A CN 201210434428 A CN201210434428 A CN 201210434428A CN 103796373 A CN103796373 A CN 103796373A
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Abstract
The invention discloses a control method for a light-emitting diode illumination system and the light-emitting diode illumination system. The light-emitting diode illumination system includes a first voltage source, a first voltage division unit, a first switch, a first clamping device, a plurality of current sources and a feedback circuit. The voltage division unit is coupled to the first voltage source. The first switch is coupled to a ground end of the voltage division circuit. The clamping device includes a plurality of transistors which are coupled to a plurality of groups of light-emitting diodes and the voltage division unit respectively. The current sources are coupled to the transistors respectively. The feedback circuit is coupled to the transistors and the plurality of groups of light-emitting diodes. Through the light-emitting diode illumination system with the clamping device, the light-emitting diode illumination system is capable of providing a short-circuit protection function when light-emitting diodes in the system are damaged so that the service life of the light-emitting diode illumination system is prolonged.
Description
Technical field
The invention relates to a kind of LED illumination system, espespecially a kind of LED illumination system that short-circuit protection function can be provided in the time that interior light emitting diodes is damaged.
Background technology
Current LED illumination system inside can comprise the light-emitting diode of multiple series connection conventionally; and excessive or while changing sharply at driving voltage; tend to cause light-emitting diode or drive circuit to damage; please refer to Fig. 1, Fig. 1 is the schematic diagram that prior art comprises the light-emitting diode (LED) illuminating circuit 10 of light-emitting diode.As shown in Figure 1, light-emitting diode (LED) illuminating circuit 10 comprises many string light-emitting diodes 16, the first end of every a string light-emitting diode 16 is to be coupled to a voltage source V DC, the second end is the first end that is coupled to an integrated circuit 14, and the first end of integrated circuit 14 is the first ends that are coupled to a current source 12, the second end of current source 12 is ground connection.In the time that the voltage of voltage source V DC sharply rises and exceedes a rated voltage, easily cause damage or the fault of light-emitting diode (LED) illuminating circuit 10.Because the voltage that is voltage source V DC at the voltage of integrated circuit 14 first ends deducts the voltage of the light-emitting diode 16 of normally working on this string light-emitting diode 16, therefore when in a string light-emitting diode 16 part LED damage and cause after short circuit, can cause the voltage of integrated circuit 14 first ends sharply rise and shorten useful life, even it is withstand voltage and cause damage to exceed drive circuit.Exceed if avoid that integrated circuit 14 is withstand voltage causes damage, integrated circuit 14 can be selected high voltage processing procedure during fabrication, but compared to low-voltage processing procedure, high voltage processing procedure needs larger area, causes the area of integrated circuit 14 excessive, and manufacturing cost is also higher.
Summary of the invention
One embodiment of the invention are about a kind of LED illumination system, and this LED illumination system comprises one first voltage source, a partial pressure unit, one first switch, a clamp device, multiple current source and a feedback circuit.This first voltage source is that one first voltage is provided, this partial pressure unit is to be coupled to this first voltage source, this first switch is to be coupled to this partial pressure unit and a ground end, this clamp device is to comprise multiple transistors, those transistorized first ends are second ends that are respectively coupled to a multi-group light-emitting diode, those transistorized control ends are to be coupled to this partial pressure unit, those current sources are to be respectively coupled to those transistorized the second ends, and this feedback circuit is the first end that is coupled to those transistorized the second ends and this multi-group light-emitting diode.
Another embodiment of the present invention is the control method about a kind of LED illumination system, this LED illumination system comprises one first voltage source, one partial pressure unit, one first switch, one clamp device, one feedback circuit, multiple current sources, multiple second switches and a short-circuit protection controller, this first voltage source is that one first voltage is provided, this partial pressure unit is to be coupled to this first voltage source, this first switch is to be coupled to this partial pressure unit and a ground end, this clamp device is to comprise multiple transistors, those transistorized first ends are second ends that are respectively coupled to a multi-group light-emitting diode, those transistorized control ends are to be coupled to this partial pressure unit, those current sources are to be respectively coupled to those transistorized the second ends, this feedback circuit is the first end that is coupled to those transistorized the second ends and this multi-group light-emitting diode, those second switches are to be respectively coupled to those current sources, and this short-circuit protection controller comprises multiple inputs and multiple output, those inputs are to be respectively coupled to those transistorized the second ends, and those outputs are the control ends that are respectively coupled to those second switches, in order to open or to close according to the current potential of those transistorized the second ends or those second switches of dim signal control, the method comprises that opening this first switch is depressed into those transistorized control ends so that this partial pressure unit is exported one point, close this first switch, and this short-circuit protection controller of activation is to detect the current potential of those transistorized the second ends.The time of this short-circuit protection controller activation is at least part overlapping of time of closing with this first switch.
By the embodiment of the present invention, LED illumination system in the inner portion have light-emitting diode damage time, provide short-circuit protection function, to increase the useful life of LED illumination system.In addition, the set selection circuit of LED illumination system of the present invention can be adjusted the voltage quasi position that exports this multi-group light-emitting diode in order to select a minimum voltage level in the current potential of those transistorized the second ends, and increases the useful life of LED illumination system.
Accompanying drawing explanation
Fig. 1 is the schematic diagram that prior art comprises the light-emitting diode (LED) illuminating circuit of light-emitting diode.
Fig. 2 is the schematic diagram of LED illumination system of the present invention.
Fig. 3 is the sequential chart that first embodiment of the invention is controlled Fig. 2 LED illumination system.
Fig. 4 is the flow chart of first embodiment of the invention control chart 2 LED illumination systems.
Fig. 5 is the sequential chart that second embodiment of the invention is controlled Fig. 2 LED illumination system.
Fig. 6 is the flow chart of second embodiment of the invention control chart 2 LED illumination systems.
Wherein, description of reference numerals is as follows:
10 light-emitting diode (LED) illuminating circuits
12 current sources
14 integrated circuits
16,35 light-emitting diodes
20 partial pressure unit
The serial of 301_ to 30_N light-emitting diode
40 clamp devices
50 clamp circuits
60 feedback circuits
70 select circuit
80 comparators
82 inputs
84 negative input ends
86 outputs
90 transducers
100 LED illumination systems
110 short-circuit protection controllers
402 to 414,602 to 614 steps
FB comparison signal
Is_1 to Is_N current source
OUT_1 to OUT_N output
SW1 the first switch
SW2_1 to SW2_N second switch
T1 to TN transistor
P1, P2, P3, P4, P5 period
V1 the first voltage
V2 dividing potential drop
V3 clamping voltage
VD1, VD2, VDN, VS1, current potential
VS2、VSN、VSW1、VSW2
VDC voltage source
The low gate level of VGL
The high gate level of VGH
VIN the first voltage source
VLED1, VLED2 cross-pressure summation
VLED1, LK, VLED2, the little cross-pressure of LK
Vth critical voltage
VR reference voltage
VOUT driving voltage
Δ VF voltage difference
Embodiment
In the middle of specification and follow-up claim, use some vocabulary to censure specific assembly.Person with usual knowledge in their respective areas should understand, and same assembly may be called with different nouns by manufacturer.This specification and follow-up claim are not used as distinguishing the mode of assembly with the difference of title, but the difference in function is used as the benchmark of distinguishing with assembly.In the whole text, in the middle of specification and follow-up claim, be an open term mentioned " comprising ", therefore should be construed to " including but not limited to ".In addition, " coupling " word is comprise directly any and be indirectly electrically connected means at this.Therefore, be to be coupled to the second device if describe first device in literary composition, represent that this first device can be directly connected in this second device, or be indirectly connected to this second device by other device or connection means.
Below coordinate appended graphic elaborating according to LED illumination system of the present invention especially exemplified by embodiment, but the scope that the embodiment providing is not contained in order to limit the present invention.
Please refer to Fig. 2, Fig. 2 is the schematic diagram of LED illumination system 100 of the present invention.As shown in Figure 2, LED illumination system 100 comprises one first voltage source V IN, a partial pressure unit 20, one first switch SW 1, multi-group light-emitting diode serial 30_1 to 30_N, a clamp device 40, a clamp circuit 50, multiple current source Is_1 to Is_N, a feedback circuit 60, multiple second switch SW2_1 to SW2_N and a short-circuit protection controller 110.The first voltage source V IN provides one first voltage V1, partial pressure unit 20 is to be coupled to the first voltage source V IN, the first switch SW 1 is to be coupled between partial pressure unit 20 and a ground end, in multi-group light-emitting diode serial 30_1 to 30_N, each group light-emitting diode is the light-emitting diode 35 that comprises multiple serial connections, clamp device 40 is to comprise that multiple transistor Ts 1 are to TN, the first end of transistor T 1 to TN is the second end that is respectively coupled to multi-group light-emitting diode serial 30_1 to 30_N, and the control end of transistor T 1 to TN is to be coupled to partial pressure unit 20, clamp circuit 50 is to be coupled between the control end and a ground end of transistor T 1 to TN, current source Is_1 to Is_N is respectively coupled between second end and a ground end of transistor T 1 to TN, feedback circuit 60 is to be coupled to the second end of transistor T 1 to TN and the first end of multi-group light-emitting diode serial 30_1 to 30_N.Although having some assemblies to be coupled to, above description in the present embodiment holds, but, the invention is not restricted to this, for example also can be set to be coupled to a low-voltage end (for the first voltage V1), or be set to be coupled to a negative voltage side, as the same in follow-up embodiment.
Second switch SW2_1 to SW2_N is respectively coupled to current source Is_1 to Is_N, in order to control whether conducting of current source Is_1 to Is_N.Short-circuit protection controller 110 comprises multiple input IN_1 to IN_N and multiple output OUT_1 to OUT_N.Input IN_1 to IN_N is the second end that is respectively coupled to transistor T 1 to TN, and multiple output OUT_1 to OUT_N are the control ends that is respectively coupled to second switch SW2_1 to SW2_N, in order to according to the unlatching of the current potential of the second end of transistor T 1 to TN or dim signal control second switch SW2_1 to SW2_N or close.Dim signal refers to the signal that second switch SW2_1 to SW2_N can be opened, closes, that is control whether conducting of current source Is_1 to Is_N, the responsibility cycle (Duty Cycle) that the luminosity of light-emitting diode serial 30_1 to 30_N can be unlocked, close according to second switch SW2_1 to SW2_N is adjusted.
In the present embodiment, clamp circuit 50 comprises a Zener diode Vz.Zener diode Vz comprises that one is coupled to the negative electrode of the control end of transistor T 1 to TN, and one is coupled to the anode of holding.But the present invention is not limited to this, clamp circuit 50 also can be set to comprise other assembly.
Please refer to Fig. 3 and Fig. 4, Fig. 3 is the sequential chart that first embodiment of the invention is controlled Fig. 2 LED illumination system 100.In Fig. 3, be from top to bottom sequentially the current potential V of the control end of the first switch SW 1
sW1, transistor T 1 to TN current potential VG, the current potential VD1 of first end of transistor T 1 and the current potential VD2 of the first end of transistor T 2, the current potential VS1 of the second end of transistor T 1 and short-circuit protection function (SCP) the temporal evolution activation of the current potential VS2 of the second end of transistor T 2 and diode illuminating system 100 and the waveform of anergy of control end.Fig. 4 is the flow chart of first embodiment of the invention control LED illumination system 100, and wherein step 402 is to 408 being corresponding period P1, and step 410, to 414 being corresponding period P2, is described as follows:
Step 402: open (conducting) first switch SW 1, so that partial pressure unit 20 is exported a dividing potential drop V2
To the control end of transistor T 1 to TN;
Step 404: select circuit 70 to choose the second end in transistor T 1 to TN and there is potential minimum
Transistorized current potential, and export the current potential of choosing to comparator 80;
Step 406: comparator 80 compares the current potential of selecting circuit 70 to transmit with reference voltage VR
, transducer 90 is exported to a comparison signal FB;
Step 408: transducer 90 is adjusted its responsibility cycle according to the comparison signal FB receiving, to adjust
The driving voltage V of whole output
oUTlevel;
Step 410: close the first switch SW 1, so that partial pressure unit 20 is exported the first voltage source V IN
In the clamping voltage V3 that the first voltage V1 of output and clamp circuit 50 are exported
One lower voltage;
Step 412: activation short-circuit protection controller 110, to detect the second end of transistor T 1 to TN
Current potential, the time that short-circuit protection controller 110 is enabled is and the first switch SW 1
At least part overlapping of the time of closing;
Step 414: the level that short-circuit protection controller 110 detects other transistor the second end (for example
VS2) (for example exceed transistorized the second end level that the second end has a minimum level
VS1), when a predetermined value, (for example close second switch that this transistor is corresponding
SW2_2)。
When the first switch SW 1 is while opening (turn on), partial pressure unit 20 can be exported a dividing potential drop V2, and the large I of the dividing potential drop V2 that exports decides according to the first voltage V1 of the resistance value of the resistance value of the first impedance, the second impedance and the first voltage source V IN output, namely
in the time that step 402 is opened the first switch SW 1, the dividing potential drop V2 that now reaches the control end of transistor T 1 to TN can be less, because the current potential VD2 of the first end of transistor T 2 equals driving voltage V
oUTlevel deduct in light-emitting diode serial 30_2 the cross-pressure summation VLED2 of the light-emitting diode of normal work, and the current potential VD1 of the first end of transistor T 1 equals driving voltage V
oUTlevel deduct the cross-pressure summation VLED1 of all light-emitting diodes in light-emitting diode serial 30_1, therefore known in the time of transistor T 1 and T2 conducting, the current potential VS1 of the second end of transistor T 1 can be less than the current potential VS2 of the second end of transistor T 2.Then in step 404, select circuit 70 can choose the positive input terminal 82 that the second end in transistor T 1 to TN has the transistorized current potential of potential minimum and exports comparator 80 to, therefore the current potential VS1 of the second end of transistor T 1 can be selected to compare with the reference voltage VR that is coupled to negative input end 84 in step 406, transducer 90 is exported to comparison signal FB from output 86.In step 408, transducer 90 can be adjusted its responsibility cycle (duty cycle) according to the comparison signal FB receiving, when judging that comparison signal FB is excessive, that is the current potential VS1 of the second end of transistor T 1 is while being greater than reference voltage VR, downgrade responsibility cycle, the anti-responsibility cycle that increases.The driving voltage V exporting by adjusting transducer 90
oUT, the current potential VS1 of the second end of transistor T 1 can be remained on to fixing level (for example VR).In step 412, carry out light-emitting diode short-circuit protection function, that is when activation (enable) short-circuit protection controller 110, can close (turn off) first switch SW 1, now dividing potential drop V2 can rise, but the received voltage quasi position of the control end of transistor T 1 to TN can be subject to the restriction of the clamping voltage V3 of clamp circuit 50, even if the level of the dividing potential drop V2 that therefore partial pressure unit 20 is exported is the level that is greater than clamping voltage V3, the voltage quasi position of the control end of transistor T 1 to TN also can not exceed the level of clamping voltage V3, and can be confined to the level of clamping voltage V3, namely VG≤V3, so can and avoid in the time that dividing potential drop V2 is excessive, make the current potential of control end of transistor T 1 to TN too high, cause the damage of transistor T 1 to TN.Note that in the present invention, short-circuit protection controller 110 also has light modulation (dimming) function except having short-circuit protection function, and its function possessing is not limited by its title.For instance; short-circuit protection controller 110 can open second switch SW2_1 to SW2_N, cut out light-emitting diode serial 30_1 to 30_N is carried out to light modulation with different frequencies/responsibility cycle by output OUT_1 to OUT_N, makes light-emitting diode serial 30_1 to 30_N can reach according to this different luminosity.
The present embodiment for example in, the light-emitting diode 35 of the light-emitting diode serial 30_1 that transistor T 1 couples is all without damaging, 35 of the light-emitting diodes of the light-emitting diode serial 30_2 that transistor T 2 couples have part to damage (short circuit), therefore represent with the light-emitting diode quantity that is less than light-emitting diode serial 30_1 in Fig. 2, but the present embodiment is not in order to limit the quantity of the included light-emitting diode of transistor of the present invention.
In the time of step 412 activation (enable) short-circuit protection controller 110; because multiple input IN_1 to IN_N of short-circuit protection controller 110 are second ends that are respectively coupled to transistor T 1 to TN, therefore can detect the current potential of the second end of transistor T 1 to TN.Because light-emitting diode serial 30_1 has part light-emitting diode to damage (or short circuit) without light-emitting diode damage and light-emitting diode serial 30_2; exceed greatly predetermined value therefore short-circuit protection controller 110 can detect the current potential of the second end of transistor T 2 than the current potential of the second end of transistor T 1, have so can detect in light-emitting diode serial 30_2 the light-emitting diode that forms short circuit because of damage.
In step 414, detect the level of the second end of transistor T 1 to TN by short-circuit protection controller 110, whether can learn in light-emitting diode serial 30_1 to 30_N has light-emitting diode serial to have the light-emitting diode of damage, and because multiple output OUT_1 to OUT_N of short-circuit protection circuit 110 are the control ends that are respectively coupled to second switch SW2_1 to SW2_N, short-circuit protection controller 110 can or cut out according to the unlatching of the control of Electric potentials second switch SW2_1 to SW2_N of the second end of detected transistor T 1 to TN, for example in the time that the current potential VS2 of the second end of transistor T 2 exceedes predetermined value greatly than the current potential VS1 of the second end of transistor T 1, judge in the light-emitting diode serial 30_2 that is coupled to transistor T 2 and have part light-emitting diode 35 to damage, therefore short-circuit protection controller 110 can cut out the second switch SW2 of transistor T 2 correspondences, so that short-circuit protection to be provided, in like manner, when detecting while having in light-emitting diode serial 30_1 to 30_N that more multi-group light-emitting diode serial has the light-emitting diode of damage, stop second switch corresponding to conducting to provide short-circuit protection to LED illumination system 100.In the present embodiment, the time that the time that short-circuit protection controller 110 is enabled closes with the first switch SW 1 should be consistent or at least part overlapping.
In addition, in period P1, because the first switch SW 1 is to open (conducting), the current potential VG of the control end of transistor T 1 to TN can equal V2, and
therefore the current potential VS2 of the second end of transistor T 2 is critical voltage Vth that the current potential VG that is equivalent to the control end of transistor T 2 deducts transistor T 2, and the current potential VD1 of the first end of transistor T 1 is driving voltage V
oUTlevel deduct the cross-pressure summation VLED1 of all light-emitting diodes in light-emitting diode serial 30_1, the current potential VD2 of the first end of transistor T 2 is driving voltage V
oUTlevel deduct the cross-pressure summation VLED2 of all still unspoiled light-emitting diodes in light-emitting diode serial 30_2.In period P2, because the first switch SW 1 is to close (not conducting), now the current potential VG of the control end of transistor T 1 to TN can become the lower voltage in the first voltage V1 of the first voltage source V IN output and clamping voltage V3 that clamp circuit 50 is exported, and the current potential VS2 of the second end of transistor T 2 is as follows:
In the time of VG-Vth<VD2, VS2=VG-Vth;
In the time of VG-Vth>VD2, VS2=VS1+ Δ VF=VR+ Δ VF.
No matter but at period P1 or P2, because second switch SW2_1 to SW2_N is in opening (conducting) state, and the current potential VS1 of the second end of transistor T 1 is transfused to the positive input terminal 82 of comparator 80, the current potential VS1 of the second end of transistor T 1 is all similar to reference voltage VR.Due to when the period P2; the current potential VS1 of the second end of transistor T 1 can equal reference voltage VR; the level of the current potential VS2 of the second end of transistor T 2 can be equivalent to (VG-Vth) or (VR+ Δ VF); therefore the time of the short-circuit protection function activation of diode illuminating system 100 must be at least part and period P2 overlap, could judge whether by the potential difference of the detecting current potential VS1 of the second end of transistor T 1 and the current potential VS2 of the second end of transistor T 2 light-emitting diode of short circuit.
In general,, because the number of the light-emitting diode 35 of short circuit or damage cannot estimate in advance, be therefore difficult to prior forecast (VG-Vth) larger with VD2 whichever.By device and method provided by the present invention; in the time only having minority light-emitting diodes tube short circuit in a string light-emitting diode 35, Δ VF is less, and VD2 is also less; therefore can be the situation of (VG-Vth) >VD2 conventionally, and VS2=VS1+ Δ VF=VR+ Δ VF now.Anti-, if when a string light-emitting diode 35 has too many LEDs short circuit, Δ VF can be larger, and VD2 is also larger, thus can be the situation of (VG-Vth) <VD2 conventionally, and VS2 will be clamped at (VG-Vth).Therefore; in the time of needs short-circuit protection function; can will be clamped at (VG-Vth) because there is the voltage VS2 of the LED2 of plurality of LEDs short circuit; and consider that integrated circuit current source Is_1 ~ Is_N's is withstand voltage simultaneously; select suitable VG (V1 or Vz); just can reach the effect of high gate voltage clamp, integrated circuit current source Is_1 ~ Is_N also just can select low-voltage processing procedure.Now, VD2 may be very high, VS2 voltage by clamp at VG-Vth, bear high pressure by transistor T 2, this is the meaning that transistor T 2 exists.Emphasis of the present invention is also to control transistor T 1 ~ TN how, makes it in the time voltage being carried out to clamp action, can also take into account short-circuit protection function.
Please refer to Fig. 5 and Fig. 6, Fig. 5 is the sequential chart that second embodiment of the invention is controlled Fig. 2 LED illumination system 100.In Fig. 5, be from top to bottom sequentially the current potential V of the control end of second switch SW2_1 to SW2_N
sW2, the first switch SW 1 the current potential V of control end
sW1, transistor T 1 current potential VS2 and the time dependent waveform of short-circuit protection function activation of the second end of current potential VS1, transistor T 2 of the second end of sequential, transistor T 1 of current potential VD2 of first end of current potential VD1, transistor T 2 of first end.Fig. 6 is the flow chart of second embodiment of the invention control LED illumination system 100, is described as follows:
Step 602: open the first switch SW 1, so that partial pressure unit 20 is exported a dividing potential drop V2 to crystal
The control end of pipe T1 to TN;
Step 604: select circuit 70 to choose the second end in transistor T 1 to TN and there is potential minimum
Transistorized current potential, and export the current potential of choosing to comparator 80;
Step 606: comparator 80 compares the current potential of selecting circuit 70 to transmit with reference voltage VR
, transducer 90 is exported to a comparison signal FB;
Step 608: transducer 90 is adjusted its responsibility cycle according to the comparison signal FB receiving, to adjust
The driving voltage V of whole output
oUTlevel;
Step 610: in the time that second switch SW2_1 to SW2_N is unlatching, close the first switch SW 1,
So that partial pressure unit 20 export the first voltage source V IN output the first voltage V1 and
A lower voltage in the clamping voltage V3 that clamp circuit 50 is exported;
Step 612: activation short-circuit protection controller 110, to detect the second end of transistor T 1 to TN
Current potential, the time that short-circuit protection controller 110 is enabled and the first switch SW 1
At least part overlapping of the time of closing;
Step 614: the level that short-circuit protection controller 110 detects other transistor the second end exceeds
When two ends have transistorized second end level one predetermined value of minimum level, close
The second end has the second switch corresponding to transistor of minimum level.
In the period of the second embodiment P3, because the first switch SW 1 is to open (conducting), the current potential VG of the control end of transistor T 1 to TN can equal V2, and
and second switch SW2_1 to SW2_N is in closing (not conducting) state, therefore the current potential VS1 of the second end of transistor T 1 and T2 and the level of VS2 can equal the current potential VG of the control end of transistor T 1 to TN (now need not to equal VR be because the output of whole LED illuminator no current to VS1, it is no-load condition, now do not fall down because conventionally there being large electric capacity to be maintained VOUT value on VOUT, LED is again because of no current, two ends cross-pressure declines rapidly, the source voltage VS1 to VSN of T1 to TN can rise, rise to VG just stops later, Source voltage can be higher than Gate voltage), because no current circulation on light-emitting diode, cross-pressure summation is very little, therefore light-emitting diode serial 30_1, the little cross-pressure VLED1 that 30_2 only has respectively due to leakage current to produce, LK, VLED2, LK, so the current potential VD1 of the first end of transistor T 1 is VOUT-VLED1, LK, approach very much VOUT, the current potential VD2 of the first end of transistor T 2 is VOUT-VLED2, LK, also approach very much VOUT.In the time of period P4, second switch SW2_1 to SW2_N is changed to unlatching (conducting) state, therefore the current potential VS1 of the second end of transistor T 1 can equal reference voltage VR, the current potential VG that the current potential VS2 of the second end of transistor T 2 can equal the control end of transistor T 2 deducts the critical voltage Vth of transistor T 2, and the current potential VD1 of the first end of transistor T 1 can be down to driving voltage V by approaching VOUT value
oUTlevel deduct the cross-pressure summation VLED1 of all light-emitting diodes in light-emitting diode serial 30_1, the current potential VD2 of the first end of transistor T 2 can be down to driving voltage V by approaching VOUT value
oUTlevel deduct the cross-pressure summation VLED2 of all still unspoiled light-emitting diodes in light-emitting diode serial 30_2.In period P5, because second switch SW2_1 to SW2_N is still in opening (conducting) state, the first switch SW 1 can be closed, the current potential VG of the control end of transistor T 1 to TN can become the lower voltage in the first voltage V1 of the first voltage source V IN output and clamping voltage V3 that clamp circuit 50 is exported, the current potential VS1 of the second end of transistor T 1 can equal reference voltage VR, and the level that the level of the current potential VS2 of the second end of transistor T 2 can be equivalent to reference voltage VR adds the voltage difference delta VF between VD2 and VD1.Due to when the period P5; the current potential VS1 of the second end of transistor T 1 can equal reference voltage VR; the level that the level of the current potential VS2 of the second end of transistor T 2 can be equivalent to reference voltage VR adds the voltage difference delta VF between VD2 and VD1; therefore the time of the short circuit current defencive function activation of diode illuminating system 100 must be at least part and period P5 overlap, could judge whether by the potential difference of the detecting current potential VS1 of the second end of transistor T 1 and the current potential VS2 of the second end of transistor T 2 light-emitting diode of short circuit.
Period P4, P5 are similar to period P1, P2 in function; when difference is period P3, illuminator is being carried out light modulation; that is; when period P3, light-emitting diode 35 can't luminous (now no current flows through); in the time of period P4, P5, light-emitting diode 35 can luminous (now having electric current to flow through), and difference between period P4 and period P5 is that short-circuit protection function is to carry out in period P5.In addition; second switch SW2_1 to SW2_N can be separately in order to light modulation (dimming); the mode of light modulation can utilize the conducting of light-emitting diode 35 and shut-in time ratio to produce an average current and/or a mean flow rate; therefore can in the time of light-emitting diode 35 conducting, carry out the periodicity detecting of short-circuit protection function, when namely second switch SW2_1 to SW2_N is unlocked.
In a second embodiment, LED illumination system 100 is set to only have when second switch SW2_1 to SW2_N is during all in opening, and just activation short-circuit protection controller 110 periodically, periodically to detect the current potential of the second end of transistor T 1 to TN.By the setting of the second embodiment, LED illumination system 100 needn't continue activation short-circuit protection controller 110, so can further save the power consumption of LED illumination system 100.
As shown in Figure 5, closing the first switch SW 1 is to carry out in the time that second switch SW2_1 to SW2_N all opens.In addition, in embodiments of the present invention, unlatching to second switch SW2_1 to SW2_N, close and comprise synchronous (synchronous) and asynchronous (asynchronous), and open, close second switch SW2_1 to SW2_N asynchronous second switch SW2_1 to SW2_N is also comprised sequentially, for example one by one second switch SW2_1 to SW2_N is opened, is closed in the mode of fixed skew, and wherein order be not defined as must according to SW2_1, SW2_2 ..., SW2_N order.
By the embodiment of the present invention, LED illumination system 100 in the inner portion have light-emitting diode damage time, provide short-circuit protection function, to increase the useful life of LED illumination system 100.In addition, the set selection circuit 70 of LED illumination system 100 of the present invention can be adjusted the voltage quasi position that exports multi-group light-emitting diode serial 30_1 to 30_N in order to select a minimum voltage level in the current potential VS1 to VSN of the second end of eleutheromorph body pipe T1 to TN, and increase the efficiency of LED illumination system, also increase the useful life of LED illumination system 100.
The foregoing is only the preferred embodiments of the present invention, be not limited to the present invention, for a person skilled in the art, the present invention can have various modifications and variations.Within the spirit and principles in the present invention all, any modification of doing, be equal to replacement, improvement etc., within all should being included in protection scope of the present invention.
Claims (14)
1. a LED illumination system, is characterized in that, comprising:
One first voltage source, in order to provide one first voltage;
One partial pressure unit, is coupled to this first voltage source;
One first switch, is coupled to this partial pressure unit and a ground end;
One clamp device, comprises multiple transistors, and those transistorized first ends are second ends that are respectively coupled to multi-group light-emitting diode, and those transistorized control ends are to be coupled to this partial pressure unit;
Multiple current sources, are respectively coupled to those transistorized the second ends; And
One feedback circuit, is coupled to the first end of those transistorized the second ends and this multi-group light-emitting diode.
2. LED illumination system as claimed in claim 1, is characterized in that, also comprises a clamp circuit, is coupled to those transistorized control ends.
3. LED illumination system as claimed in claim 1, is characterized in that, this feedback circuit comprises:
One selects circuit, is coupled to those transistorized the second ends, in order to export current potential minimum in those transistorized second ends;
One comparator, comprising:
One positive input terminal, is coupled to this selection circuit;
One negative input end, in order to receive a reference voltage; And
One output, in order to export a comparison signal according to current potential and this reference voltage of this selection circuit output; And
One transducer, is coupled to the first end of this multi-group light-emitting diode and the output of this comparator, in order to according to this comparison signal, adjusts the voltage quasi position that exports this multi-group light-emitting diode to.
4. LED illumination system as claimed in claim 1, is characterized in that, also comprises:
Multiple second switches, are respectively coupled to those current sources; And
One short-circuit protection controller, comprising:
Multiple inputs, are respectively coupled to those transistorized the second ends; And
Multiple outputs, are respectively coupled to the control end of those second switches, in order to open or to close according to the current potential of those transistorized the second ends or those second switches of dim signal control.
5. LED illumination system as claimed in claim 1, is characterized in that, this partial pressure unit comprises:
One first impedance, is coupled to this first voltage source; And
One second impedance, is coupled between this first impedance and this ground end.
6. LED illumination system as claimed in claim 2, is characterized in that, this clamp circuit comprises:
One Zener diode, comprises that one is coupled to the negative electrode of those transistorized control ends, and one is coupled to the anode that this ground is held.
7. the control method of a LED illumination system, this LED illumination system comprises one first voltage source, one partial pressure unit, one first switch, one clamp device, multiple current sources, one feedback circuit, multiple second switches and a short-circuit protection controller, this first voltage source is that one first voltage is provided, this partial pressure unit is to be coupled to this first voltage source, this first switch is to be coupled to this partial pressure unit and a ground end, this clamp device comprises multiple transistors, those transistorized first ends are second ends that are respectively coupled to multi-group light-emitting diode, those transistorized control ends are to be coupled to this partial pressure unit, those current sources are to be respectively coupled to those transistorized the second ends, this feedback circuit is the first end that is coupled to those transistorized the second ends and this multi-group light-emitting diode, those second switches are to be respectively coupled to those current sources, and this short-circuit protection controller comprises multiple inputs and multiple output, those inputs are to be respectively coupled to those transistorized the second ends, and those outputs are the control ends that are respectively coupled to those second switches, in order to open or to close according to the current potential of those transistorized the second ends or those second switches of dim signal control, the method is characterized in that, comprise:
Open this first switch, be depressed into those transistorized control ends so that this partial pressure unit is exported one point;
Close this first switch; And
This short-circuit protection controller of activation, to detect the current potential of those transistorized the second ends;
Wherein the time of this short-circuit protection controller activation is at least part overlapping of time of closing with this first switch.
8. method as claimed in claim 7, it is characterized in that, this LED illumination system also comprises a clamp circuit, be coupled to those transistorized control ends, wherein, in the time that this first switch is closed, this partial pressure unit is to export voltage lower in the first voltage of this first voltage source output and the clamping voltage of this clamp circuit output to control those transistors.
9. method as claimed in claim 7, is characterized in that, also comprises that this short-circuit protection controller cuts out at least one second switch according to the current potential of those transistorized the second ends, to stop this at least one second switch of conducting.
10. method as claimed in claim 7, is characterized in that, in the time that those second switches are closed condition, this first switch is opening.
11. methods as claimed in claim 7, is characterized in that, also comprise asynchronous unlatching and close those second switches, and wherein closing this first switch is to carry out in the time that those second switches are all opened.
12. methods as claimed in claim 11, is characterized in that, asynchronous unlatching and to close those second switches be sequentially to open and close those second switches.
13. methods as claimed in claim 7, is characterized in that, when those second switches are during in opening, this short-circuit protection controller is to be periodically enabled, periodically to detect the current potential of those transistorized the second ends.
14. methods as claimed in claim 7, it is characterized in that, this feedback circuit comprises a selection circuit, a comparator and a transducer, this selection circuit is to be coupled to those transistorized the second ends, this comparator comprises that a positive input terminal, that is coupled to this selection circuit is in order to receive negative input end and an output of a reference voltage, this transducer is to be coupled to the first end of this multi-group light-emitting diode and the output of this comparator, it is characterized in that, also comprises:
This selection circuit is exported current potential minimum in those transistorized second ends;
This comparator is exported a comparison signal according to current potential and this reference voltage of this selection circuit output; And
This transducer exports the voltage quasi position of this multi-group light-emitting diode to according to this comparison signal adjustment.
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| TWI594664B (en) * | 2016-08-17 | 2017-08-01 | 緯創資通股份有限公司 | Light-emitting diode driving device and short protection method for driving device |
| US10051712B2 (en) | 2016-12-02 | 2018-08-14 | Industrial Technology Research Institute | Driving module and light source system having the driving module |
| CN108811231A (en) * | 2017-05-05 | 2018-11-13 | 东莞艾笛森光电有限公司 | Dimming Optimized LED Driver Circuit |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101534594A (en) * | 2008-03-12 | 2009-09-16 | 奇美电子股份有限公司 | Short-circuit protection circuit of light-emitting diode string and method thereof |
| CN101917809A (en) * | 2010-08-24 | 2010-12-15 | 成都芯源系统有限公司 | Driver for driving a plurality of light emitting elements, driving method, and display device |
| CN101990337A (en) * | 2009-08-03 | 2011-03-23 | 联咏科技股份有限公司 | Light source drive device capable of dynamically maintaining constant current drive and related method |
| CN102256418A (en) * | 2011-07-15 | 2011-11-23 | 深圳市华星光电技术有限公司 | PWM (pulse width modulation) dimming circuit |
| CN102348311A (en) * | 2010-08-02 | 2012-02-08 | 艾笛森光电股份有限公司 | Light emitting diode driving circuit |
| US20120146523A1 (en) * | 2010-12-11 | 2012-06-14 | Jae Hong Jeong | Light emitting diode driver |
-
2012
- 2012-11-02 CN CN201210434428.8A patent/CN103796373B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101534594A (en) * | 2008-03-12 | 2009-09-16 | 奇美电子股份有限公司 | Short-circuit protection circuit of light-emitting diode string and method thereof |
| CN101990337A (en) * | 2009-08-03 | 2011-03-23 | 联咏科技股份有限公司 | Light source drive device capable of dynamically maintaining constant current drive and related method |
| CN102348311A (en) * | 2010-08-02 | 2012-02-08 | 艾笛森光电股份有限公司 | Light emitting diode driving circuit |
| CN101917809A (en) * | 2010-08-24 | 2010-12-15 | 成都芯源系统有限公司 | Driver for driving a plurality of light emitting elements, driving method, and display device |
| US20120146523A1 (en) * | 2010-12-11 | 2012-06-14 | Jae Hong Jeong | Light emitting diode driver |
| CN102256418A (en) * | 2011-07-15 | 2011-11-23 | 深圳市华星光电技术有限公司 | PWM (pulse width modulation) dimming circuit |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| TWI594664B (en) * | 2016-08-17 | 2017-08-01 | 緯創資通股份有限公司 | Light-emitting diode driving device and short protection method for driving device |
| US10051712B2 (en) | 2016-12-02 | 2018-08-14 | Industrial Technology Research Institute | Driving module and light source system having the driving module |
| CN108811231A (en) * | 2017-05-05 | 2018-11-13 | 东莞艾笛森光电有限公司 | Dimming Optimized LED Driver Circuit |
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|---|---|
| CN103796373B (en) | 2016-05-11 |
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