CN103068093B - Control method of light-emitting diode bunch - Google Patents
Control method of light-emitting diode bunch Download PDFInfo
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- CN103068093B CN103068093B CN201110318282.6A CN201110318282A CN103068093B CN 103068093 B CN103068093 B CN 103068093B CN 201110318282 A CN201110318282 A CN 201110318282A CN 103068093 B CN103068093 B CN 103068093B
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Abstract
The invention provides a control method suitable for driving a plurality of light-emitting diode bunches. The control method of the light-emitting diode includes: driving the plurality of light-emitting diode bunches with an output power, providing each light-emitting diode bunch with corresponding short-circuit protection, testing the plurality of light-emitting diode bunches to see whether an under-current accident happens to the brunches, stopping providing short-circuit protection for all the light-emitting diode bunches if under-current accident happens to any one of the plurality of light-emitting diode bunches, testing the output power to see whether standard security is met, and providing a light-emitting diode which gives out light normally with corresponding short-circuit protection when the output power meets standard of security, wherein, under-current accident never happens to the light-emitting diode which gives out light normally.
Description
Technical field
The invention relates to the control method circuit for several light-emitting diodes pipe strings (LED chain), the control method of especially protecting about the short-and-medium road of light-emitting diodes pipe string.
Background technology
For these epoch of exquisite carbon reduction, light-emitting diode (light-emitting diode, LED) has been a kind of light source widely using, because it has quite good luminous efficiency and exquisite component size.For instance, modern LCD screen (LCD panel), mostly replaces CCFL in the past with LED, is used as backlight.
Fig. 1 is a kind of LED power supply unit 18 of the backlight module for LCD screen, is mainly to control light-emitting diodes pipe string L
1～L
nluminous, each light-emitting diodes pipe string has the light-emitting diode of several serial connections.The power switch that backlight controller 20 is controlled in booster circuit (booster) 19, makes inductance element draw energy from input IN, and output OUT is released energy, to set up suitable output voltage V on output OUT
oUTdrive light-emitting diodes pipe string.Backlight controller 20 is by overvoltage protection end OVP, divider resistance RD
1with RD
2, detect output voltage V
oUT.
Backlight controller 20 also make to flow through simultaneously each light-emitting diodes pipe string electric current about equally, to reach the object of uniformly light-emitting.Current sense resistor RS
1～RS
ndetect and flow through light-emitting diodes pipe string L respectively
1～L
ndrive current, testing result is by current detecting end CS
1～CS
ngive backlight controller 20.Backlight controller 20 is controlled nmos pass transistor N according to this
1～N
nimpedance, drive current is approximately all equated.
The feedback end FB of backlight controller 20
1～FB
n, pass through resistance R
1～R
n, approximately detect light-emitting diodes pipe string L
1～L
nnegative electrode D
1～D
n.From feedback end FB
1～FB
nthe information of receiving, backlight controller 20 can make booster circuit 19 operate in a more efficient state.On the other hand, backlight controller 20 also can be from feedback end FB
1～FB
ndifferentiate and whether have light-emitting diode that open circuit or the problem of short circuit occur, trigger corresponding open-circuit-protection or short-circuit protection.For instance, if feedback end FB
1on feedback voltage V
fB-10 voltage always, that light-emitting diodes pipe string L
1may be an open circuit light-emitting diodes pipe string, wherein have at least one diode to open a way, that backlight controller 20 be just closed light-emitting diodes pipe string L
1driving.For another example, if feedback end FB
2on feedback voltage V
fB-2far above feedback end FB
1on feedback voltage V
fB-1, the short-circuit protection in that backlight controller 20 may identify light-emitting diodes pipe string L
2in to have some light-emitting diodes are short circuits, therefore close light-emitting diodes pipe string L
2driving.
Just, open-circuit-protection and short-circuit protection each other, may disturb mutually.So need to have reasonable time program deactivation or close open circuit and short-circuit protection, so, just can reflect and really want the protection effect that obtains.
Summary of the invention
Embodiments of the invention disclose a kind of control method, are applicable to drive the luminous of several light-emitting diodes pipe strings.Include: detect these light-emitting diodes pipe strings, carry out voltage stabilizing one out-put supply, wherein, this out-put supply is in order to drive these light-emitting diodes pipe strings; Control several drive currents, its these light-emitting diodes pipe strings of flowing through respectively; Whether one of them occurs one and crosses low current event to detect at least these drive currents, wherein, one open circuit light-emitting diodes pipe string is crossed a light-emitting diodes pipe string of low current event for there is this, and a normal light-emitting diodes pipe string is not for the light-emitting diodes pipe string that this crosses low current event occurs; When this crosses the generation of low current event, stop these light-emitting diodes pipe strings that short-circuit protection is provided; Detect this out-put supply whether one mistake high pressure event occurs; When this crosses high pressure event generation, stop this out-put supply of voltage stabilizing; Detect this out-put supply and whether return to a safety standard; And, when this out-put supply returns to after this safety standard, recover this out-put supply of voltage stabilizing, and recover this normal light-emitting diode that this short-circuit protection is provided.
Embodiments of the invention also disclose a kind of control method, are applicable to drive the luminous of several light-emitting diodes pipe strings, include: with an out-put supply, drive these light-emitting diodes pipe strings; To these light-emitting diodes pipe strings, provide corresponding short-circuit protection respectively; Detect these light-emitting diodes pipe strings whether one mistake low current event occurs; If this crosses low current event the arbitrary generation wherein of these light-emitting diodes pipe strings, stop all light-emitting diodes pipe strings that these short-circuit protections are provided; Detect this out-put supply and whether reach a safety standard; And when this out-put supply reaches after this safety standard, recovering provides a corresponding short-circuit protection to a normal light-emitting diode; Wherein, there is not this and cross low current event in this normal light-emitting diode.
Accompanying drawing explanation
Fig. 1 is a kind of LED power supply unit of the backlight module for LCD screen.
The backlight controller of Fig. 2 for implementing according to the present invention.
Fig. 3 shows a kind of control method of implementing according to the present invention.
Fig. 4 shows while carrying out according to the control method of Fig. 3, some signal timing diagrams in Fig. 2.
[main element label declaration]
18 LED power supply unit 19 booster circuits
20 backlight controllers 22
1～22
nlED short circuit detector
24
1lED string driver 26 minimum voltage selectors
28
1～28
ndriver module 30 pulse-width controllers
32
1lED open circuit detector 34
1logical circuit
60 control methods
62,64,66,68,70,72,74,76,78 steps
CS
1～CS
ncurrent detecting end D
1～D
nnegative electrode
DRV drive end EN
1enable signal
ENSH
1～ENSH
nshort-circuit protection enable signal ENSH
gshort-circuit protection enable signal
FB
1～FB
nfeedback end FB-MIN minimum feedback end
G
1～G
ndoor end IN input
L
1～L
nlight-emitting diodes pipe string L
gnormal light-emitting diodes pipe string
N
1～N
nnMOS transistor OP
1signal
OUT output OVP overvoltage protection end
R
1～R
nresistance R D
1, RD
2divider resistance
RS
1～RS
ncurrent sense resistor SH
1signal
T
oP, t
oVP, t
rCVtime point V
cS-1current detection voltage
V
cS-Gcurrent detection voltage V
cS-TARpreset value
V
dRVdrive signal V
g-Xgate voltage
V
fB-1～V
fB-Nfeedback voltage V
fB-Gfeedback voltage
V
fB-MINminimum feedback voltage V
fB-TARfeedback preset value
V
oVPvoltage V
oUT-OVPcross high pressure preset value
V
oUToutput voltage
Embodiment
The backlight controller 20 of Fig. 2 for implementing according to the present invention.Backlight controller 20 is held G by door
1～G
n, control nmos pass transistor N
1～N
n; From current detecting end CS
1～CS
n, roughly detect the nmos pass transistor N that flows through
1～N
ndrive current.Backlight controller 20 is also from drive end DRV, controls the power switch in booster circuit 19, so that inductance energization wherein or release energy.In one embodiment, backlight controller 20 is a monocrystalline integrated circuit.
As shown in Figure 2, backlight controller 20 includes pulse-width controller 30, minimum voltage selector 26 and several driver module 28
1～28
n.
Minimum voltage selector 26 can be according to feedback end FB
1～FB
non feedback voltage V
fB-1～V
fB-Nin minimum value, on minimum feedback end FB-MIN, produce minimum feedback voltage V
fB-MIN.From drive end DRV, the power switch that pulse-width controller 30 is controlled in booster circuit 19, so that the voltage V of output OUT
oUTincrease or reduce, object is to make minimum feedback voltage V
fB-MINroughly maintain a feedback preset value.So, can make nmos pass transistor N
1～N
nwork more efficiently.For instance, pulse-width controller 30 is by minimum feedback voltage V
fB-MINbe controlled at about 1V, relatively feedback voltage V
fB-1～V
fB-Nin minimum value may be also approximately 1V.
Driver module 28
1～28
ncorrespond to respectively light-emitting diodes pipe string L
1～L
n.Driver module 28
1～28
ncircuit wherein, framework or function can be identical or similar.Below will be with driver module 28
1as an example, explain orally.Those skilled in the art can be according to driver module 28
1explanation, know by inference simply or realize other driver module 28
2～28
ninternal structure, annexation and function.
Driver module 28
1there is LED short circuit detector 22
1, LED open circuit detector 32
1, logical circuit 34
1, and LED string driver 24
1.
As enable signal EN
1for activation, mean light-emitting diodes pipe string L
1should be luminous, LED string driver 24
1by door end G
1and current detecting end CS
1, light-emitting diodes pipe string L haply makes to flow through
1drive current be a predetermined value.Enable signal EN
1during for forbidden energy, LED string driver 24
1by door end G
1, make nmos pass transistor N
1fixedly maintain and close, present open-circuit condition, cause greatly light-emitting diode string L
1not luminous.Meanwhile, the enable signal EN of forbidden energy
1also can make minimum feedback voltage V
fB-MINbe not subject to feedback end FB
1on feedback voltage V
fB-1institute affects.In other words, the enable signal EN of forbidden energy (disabled)
1completely cut off minimum feedback voltage V
fB-MINwith feedback end FB
1.
LED short circuit detector 22
1be couple to feedback end FB
1, by short-circuit protection enable signal ENSH
1during institute activation, judge whether according to this light-emitting diodes pipe string L
1there is LED short circuit event, so that corresponding protection mechanism to be provided.In one embodiment, work as feedback voltage V
fB-1while being clamped at 5V, and from resistance R
1flow into feedback end FB
1electric current I
fB-1surpass certain value, LED short circuit detector 22
1just assert light-emitting diodes pipe string L
1there is LED short circuit event.If LED short circuit detector 22
1assert light-emitting diodes pipe string L
1there is LED short circuit event, just by signal SH
1, and logical circuit 34
1, the enable signal EN that forced forbidden energy
1, also forbidden energy LED string driver 24
1, and completely cut off minimum feedback voltage V
fB-MINwith feedback end FB
1.As short-circuit protection enable signal ENSH
1during for forbidden energy, LED short circuit detector 22
1can forbidden energy enable signal EN
1.
LED open circuit detector 32
1whether to detect light-emitting diodes pipe string L
1there is LED open circuit event, so that corresponding protection mechanism to be provided.For instance, as light-emitting diodes pipe string L
1while there is open circuit event, feedback voltage V
fB-1and current detection voltage V
cS-1can maintain always and be close to 0V, so minimum feedback voltage V now
fB-MINalso large appointment is 0V.Yet pulse-width controller 30 is in order to draw high minimum feedback voltage V
fB-INto about 1V, so can constantly draw high the output voltage V of output OUT
oUT.Because light-emitting diodes pipe string L
1there is open circuit event, the output voltage V of drawing high
oUTcan't be to feedback voltage V
fB-1there is any impact.So, output voltage V
oUTcan constantly be drawn high, until there is an overvoltage event (over voltage event).Therefore, in one embodiment, when backlight controller 20 is found the voltage V on overvoltage protection end OVP
oVPan overvoltage preset value that has surpassed overvoltage protection, and feedback voltage V
fB-1or current detection voltage V
cS-1during lower than 0.2V, just assert light-emitting diodes pipe string L
1there is open circuit event.LED open circuit detector 32
1assert light-emitting diodes pipe string L
1while having LED open circuit event, just by signal OP
1, and logical circuit 34
1, force forbidden energy enable signal EN
1, forbidden energy (disable) LED string driver 24
1, and completely cut off minimum feedback voltage V
fB-MINwith feedback end FB
1.
But, the identifying of LED open circuit event, the LED short circuit event of other light-emitting diodes pipe string that may cause misidentification.For instance, suppose light-emitting diodes pipe string L
1really there is open circuit, and light-emitting diodes pipe string L
2normally, that output voltage V
oUTcan constantly be drawn high, so feedback voltage V
fB-2also drawn high together.That when also not arriving overvoltage event, LED short circuit detector 22
2just may be from feedback end FB
2resulting information, misidentification light-emitting diodes pipe string L
2there is LED short circuit event, so forbidden energy LED string driver 24 mistakenly
2.
Fig. 3 shows a kind of control method 60 of implementing according to the present invention.Please also refer to the backlight controller 20 of Fig. 2.In this manual, an open circuit light-emitting diodes pipe string means to be identified the light-emitting diodes pipe string that LED open circuit event occurs; One short circuit light-emitting diodes pipe string means to be identified the light-emitting diode that LED short circuit event occurs; One normal light-emitting diodes pipe string means not also to be identified a light-emitting diodes pipe string of LED open circuit or short circuit event.
In step 62, backlight controller 20 is by feedback end FB
1～FB
n, detect the negative electrode of normal light-emitting diodes pipe string, control the power switch in booster circuit 19, with the output voltage V of output end of pressure-stabilizing OUT
oUT, object is to make minimum feedback voltage V
fB-INapproximately be stabilized in feedback preset value V
fB-TAR, 1V for example.The output voltage V of output OUT
oUTfor driving light-emitting diodes pipe string L
1～L
n.
Meanwhile, in step 62, backlight controller 20 is controlled the drive current of all normal light-emitting diodes pipe strings of flowing through.For instance, in a start (startup) process, backlight controller 20 can be assert all light-emitting diodes pipe string L at the beginning
1～L
nall normal light-emitting diodes pipe string, so backlight controller 20 is held G by door
1～G
n, control nmos pass transistor N
1～N
nimpedance, equal to control the light-emitting diodes pipe string L that flows through
1～L
ndrive current.
In step 64, whether backlight controller 20 checks minimum feedback voltage V
fB-MINor there is any one normal light-emitting diodes pipe string L
xcorresponding current detection voltage V
cS-Xtoo low.At this, X is an integer among 1～N.For instance, brownout means that voltage is less than a preset value, for example 0.2V.If minimum feedback voltage V
fB-MINor current detection voltage V
cS-Xtoo low, that just means that having occurred one crosses low current event: have at least the drive current of a light-emitting diodes pipe string too low, control method 60 enters step 66.In another embodiment, identification light-emitting diodes pipe string L
xhaving met with the condition of crossing low current event, may be current detection voltage V
cS-Xlower than a preset value, and at door end G
xon gate voltage V
g-Xhigher than another preset value.If cross low current event, do not occur, control method 60 enters step 68.Cross low current event and occur, may have two kinds of reasons: 1. the output voltage V of output OUT
oUTnot high enough, be not enough to drive a light-emitting diodes pipe string, this generally occurs in the process of just having started shooting; Or there is open circuit event in a light-emitting diodes pipe string 2., so minimum feedback voltage V
fB-MINor current detection voltage V
cS-Xcannot be output voltage V at all
oUTinstitute affects.
In step 66, backlight controller 20 is by short-circuit protection enable signal ENSH
1～ENSH
n, all LED short circuit detector 22
1～22
nwhole forbidden energy.That is to say, to all light-emitting diodes pipe string L
1～L
nshort-circuit protection is not provided.
In step 68, backlight controller 20 is by short-circuit protection enable signal ENSH
1～ENSH
n, the normal corresponding LED short circuit detector of light-emitting diodes pipe string activation.
After step 66 and 68, all follow step 70, wherein, backlight controller 20, by overvoltage protection end OVP, detects the output voltage V of output OUT
oUT, look at whether to occur one and cross high pressure event (over voltage).For instance, the voltage V on overvoltage protection end OVP
oVPwhile having surpassed an overvoltage preset value, backlight controller 20 assert that high pressure event occurred.If cross high pressure event, do not occur, because cannot definitely judge LED open circuit event, so get back to step 62, pulse-width controller 30 operates normally, and normal light-emitting diode is driven and luminous.If high pressure event occurs, assert LED open circuit event has occurred, carry out step 72.
Note that when the stable state of normal running, backlight controller 20 is understood follow procedures 62,64,68 and 70 formed loops (loop) and is operated.So, cross high pressure event and do not occur, and all normal LED light-emitting diodes pipe strings are all enjoyed short-circuit protection.
In a start process, because the voltage V of output OUT
oUTnot high enough, thus backlight controller 20 may be for some time in follow procedures 62,64,66 and 70 formed loops (loop) and operating.In other words, in start process, all LED light-emitting diodes all do not have short-circuit protection.This loop, completes in start, output voltage V
oUTenough high, made after low current event disappears, will stop, and another loop while entering the stable state of previously introducing.
As long as while having LED that open circuit occurs, backlight controller 20 also can be for some time in follow procedures 62,64,66 and 70 formed loops (loop) and operating.Now, the same, all LED light-emitting diodes pipe strings all do not have short-circuit protection.This can be avoided misidentification to have LED short circuit event to occur.This loop, is identified while occurring crossing high pressure event, will stop, and enters step 72, starts to carry out and assert have LED open circuit event that the lower step that will carry out occurs.
In step 72, backlight controller 20 stop pulse width control devices 30, the power switch in booster circuit 19 is held to close, so stop electric energy transmitting, gives output OUT, output voltage V
oUTno longer raise.This can be avoided output voltage V
oUTtoo high and damage is to some more fragile circuit elements.Then perform step 74.
As long as step 64 is crossed low current event and step 70 and crossed high pressure event and all occur, that just can roughly confirm that the LED event of opening a way has occurred which light-emitting diodes pipe string.For instance, if found light-emitting diodes pipe string L when step 64
0drive current too low, that to occurred after high pressure event step 74 time, roughly just can determine light-emitting diodes pipe string L
0it is an open circuit light-emitting diodes pipe string.In step 74, the backlight controller 20 light-emitting diodes pipe string that makes to open a way is no longer driven, and allows minimum feedback voltage V
fB-MINthe light-emitting diodes pipe string of not opened a way affects.For instance, if light-emitting diodes pipe string L
1by LED open circuit detector 32
1discovery is an open circuit light-emitting diodes pipe string, and LED open circuit detector 32
1by signal OP
1and enable signal EN
1, forbidden energy LED string driver 24 on the one hand
1, make on the other hand minimum voltage selector 26 completely cut off minimum feedback voltage V
fB-MINwith feedback end FB
1.And now all LED light-emitting diodes pipe strings all do not have short-circuit protection.
Now, remaining normal light-emitting diodes pipe string, is still driven by its corresponding LED string driver and luminous.Therefore, the electric energy that leaves output OUT in is just gradually consumed, output voltage V
oUTstart to decline.
Step 76 detects the voltage V of output OUT
oUTwhether along with normal light-emitting diodes pipe string is luminous, and return to a safety standard.In one embodiment, this safety standard represents voltage V
oVPdropped to previously described below 80% of overvoltage preset value.In another embodiment, this safety standard represents minimum feedback voltage V
fB-MINdropped to below previously described feedback preset value.Step 76 constantly checks, until the output voltage V of output OUT
oUTafter returning to that safety standard, just enter step 78.
In step 78, backlight controller 20 is by short-circuit protection enable signal ENSH
1～ENSH
n, to normal light-emitting diode string, provide short-circuit protection.As for short circuit or open circuit light-emitting diodes pipe string because do not have driven, so the also unnecessary short-circuit protection that provides.
Method 60 then performs step 62.Now, minimum feedback voltage V
fB-INto only can be subject to the feedback end impact of normal light-emitting diodes pipe string, and can not be subject to short circuit or the feedback end impact of open circuit light-emitting diodes pipe string.In other words, short circuit or open circuit light-emitting diodes pipe string can not affect minimum feedback voltage V
fB-MINor voltage V
oUTvoltage stabilizing.Therefore, backlight controller 20 can normal running.
Fig. 4 shows while carrying out according to the control method 60 of Fig. 3, some signal timing diagrams in Fig. 2.In Fig. 4, suppose light-emitting diodes pipe string L
1at time point t
oPtime, become open circuit; And light-emitting diodes pipe string L
git is a normal light-emitting diodes pipe string.In Fig. 4, from top to bottom, show respectively the output voltage V of output OUT
oUT, drive end DRV driving signal V
dRV, corresponding normal light-emitting diodes pipe string L
gfeedback voltage V
fB-G, respective leds string L
1feedback voltage V
fB-1, minimum feedback voltage V
fB-MIN, corresponding normal light-emitting diodes pipe string L
gcurrent detection voltage V
vS-G, respective leds string L
1current detection voltage V
cS-1, and, corresponding normal light-emitting diodes pipe string L
gshort-circuit protection enable signal ENSH
g.
At time point t
oPbefore, suppose all light-emitting diodes pipe string L
1～L
nall the same also all normal.Now, drive signal V
dRVperiodically switch, carry out power supply conversion, output voltage V
oUTroughly a value.This value makes feedback voltage V
fB-1, feedback voltage V
fB-Gand minimum feedback voltage V
fB-MINall be stabilized in and approximately feed back preset value V
fB-TAR.Current detection voltage V
cS-Gand V
cS-1also be stabilized in preset value V
cS-TAR, show the light-emitting diodes pipe string L that flows through
gwith L
1drive current be approximately to equate and be normal.
At time point t
oPtime, light-emitting diodes pipe string L
1become open circuit.Because drive current suddenly disappears, so current detection voltage V
cS1and feedback voltage V
fB-1become fast 0V, also cause jointly minimum feedback voltage V
fB-MINbe declined to become 0V.Disclosed as the step 66 in Fig. 3, minimum feedback voltage V detected
fB-MINor current detection voltage V
cS-1after too low, all light-emitting diodes pipe string L
1～L
nshort-circuit protection is not provided, therefore, short-circuit protection enable signal ENSH
gfrom activation transition, it is forbidden energy.
At time point t
oPafterwards, backlight controller 20 is in order to draw high minimum feedback voltage V
fB-MIN, can increase its electric energy conversion, so voltage V
oUTgradually rise.Feedback voltage V
fB-Gcan follow output voltage V
oUTrising and rise.Just, because light-emitting diodes pipe string L
1become open circuit, so the voltage V drawing high
oUTto feedback voltage V
fB-1do not have any impact completely, so feedback voltage V
fB-1with minimum feedback voltage V
fB-MINcan rest on 0V always.
At time point t
oVPtime, backlight controller 20, by the detection of overvoltage protection end OVP, is found output voltage V
oUTsurpassed and crossed high pressure preset value V
oUT-OVP, confirmed that high pressure event occurred.As the step 72 of Fig. 3, instruct, drive signal V
dRVbecome and be fixed on 0V, electric energy conversion stops, so output voltage V
oUTno longer rise.Now, feedback voltage V on the low side
fB-1can allow backlight controller 20 confirm light-emitting diodes pipe string L
1there is open circuit event, so backlight controller 20 no longer drives light-emitting diodes pipe string L
1, and make minimum feedback voltage V
fB-MINwith feedback voltage V
fB-1be isolated.Therefore, minimum feedback voltage V
fB-INcan get started reaction feedback voltage V
fB-G.
At time point t
oVPafterwards, light-emitting diodes pipe string L
gstill luminous, so current detection voltage V
cS-Gstill approximately be stabilized in preset value V
cS-TAR.Along with light-emitting diodes pipe string L
gpower consumption, voltage V
oUTdecline, the related feedback voltage V that makes
fB-Gwith minimum feedback voltage V
fB-MINdecline together.
At time point t
rCVtime, backlight controller 20 is found voltage V
oVPor minimum feedback voltage V
fB-MINreached a safety standard, institute is so that short-circuit protection enable signal ENSH
gtransition is activation, and starting provides short-circuit protection to normal light-emitting diode string, as the step 78 in Fig. 3, instructs.Meanwhile, drive signal V
dRVthe switching of restore cycle property, starts converting electrical energy.Therefore, after a period of time, feedback voltage V
fB-Gand minimum feedback voltage V
fB-MINbe stabilized in approximately again feedback preset value V
fB-TAR.
From Fig. 4 and Fig. 3, can find, at time point t
oPwith time point t
rCVbetween, all light-emitting diodes pipe string L
1～L
nshort-circuit protection be all disabled, therefore, can not judge any short circuit event by accident.And, in an embodiment of the present invention, only have voltage V
oVPor minimum feedback voltage V
fB-MINreach after safety standard, the short-circuit protection of normal light-emitting diodes pipe string just can be enabled, and can prevent to open too early short-circuit protection, and may cause judging by accident the result of short circuit event.
The foregoing is only preferred embodiment of the present invention, all equalizations of doing according to the claims in the present invention scope change and modify, and all should belong to covering scope of the present invention.
Claims (13)
1. a control method, for driving the luminous of several light-emitting diodes pipe strings, includes:
Detect this several light-emitting diodes pipe strings, carry out voltage stabilizing one out-put supply, wherein, this out-put supply is in order to drive this several light-emitting diodes pipe strings;
Control several drive currents, its these several light-emitting diodes pipe strings of flowing through respectively;
Whether one of them occurs one and crosses low current event to detect at least these several drive currents, wherein, one open circuit light-emitting diodes pipe string is crossed a light-emitting diodes pipe string of low current event for there is this, and a normal light-emitting diodes pipe string is not for the light-emitting diodes pipe string that this crosses low current event occurs;
When this crosses the generation of low current event, stop these several light-emitting diodes pipe strings that short-circuit protection is provided;
Detect this out-put supply whether one mistake high pressure event occurs;
When this crosses high pressure event generation, stop this out-put supply of voltage stabilizing;
Detect this out-put supply and whether return to a safety standard; And
When this out-put supply returns to after this safety standard, recover this out-put supply of voltage stabilizing, and recover this normal light-emitting diode that this short-circuit protection is provided.
2. control method according to claim 1, also includes:
When this crosses high pressure event generation, make this open circuit light-emitting diodes pipe string no longer affect the voltage stabilizing of this out-put supply.
3. control method according to claim 1, wherein, these several light-emitting diodes pipe strings have several feedback ends, and the step of this this out-put supply of voltage stabilizing is according to the minimum feedback voltage in these several feedback ends.
4. control method according to claim 3, wherein, when this minimum feedback voltage is during lower than a preset value, at least these several drive currents one of them there is this and cross low current event.
5. control method according to claim 3, wherein,
When an output voltage of this out-put supply surpasses a default overvoltage value, this is crossed high pressure event and occurs; And
When this minimum feedback voltage is preset safety value lower than one, this out-put supply returns to this safety standard.
6. control method according to claim 3, also includes:
When this is crossed high pressure event and occurs, a corresponding feedback end of isolated this minimum feedback voltage and this light-emitting diodes pipe string of opening a way.
7. control method according to claim 1, includes:
From several current detecting ends, whether one of them there is a mistake low current event to detect these several drive currents;
Wherein, each current detecting end is connected to the current sense resistor of a correspondence.
8. control method according to claim 1, wherein, these several light-emitting diodes pipe strings have several feedback ends, and this short-circuit protection is to trigger according to the corresponding feedback voltage of a protected light-emitting diodes pipe string.
9. control method according to claim 1, wherein,
When an output voltage of this out-put supply surpasses a default overvoltage value, this is crossed high pressure event and occurs; And
When this output voltage is preset safety value lower than one, this out-put supply returns to this safety standard.
10. control method according to claim 1, includes:
According to these several light-emitting diodes pipe strings, control a switch type power supplying device, with this out-put supply of voltage stabilizing.
11. control methods according to claim 1, include:
Control this several drive currents, make each all be approximately a predetermined current value.
12. 1 kinds of control methods, for driving the luminous of several light-emitting diodes pipe strings, include:
With an out-put supply, drive this several light-emitting diodes pipe strings;
To these several light-emitting diodes pipe strings, provide corresponding short-circuit protection respectively;
Detect these several light-emitting diodes pipe strings whether one mistake low current event occurs;
If this crosses low current event this several light-emitting diodes pipe strings arbitrary generation wherein, stop all light-emitting diodes pipe strings that this short-circuit protection is provided;
Detect this out-put supply and whether reach a safety standard; And
When this out-put supply reaches after this safety standard, recovering provides a corresponding short-circuit protection to a normal light-emitting diode;
Wherein, there is not this and cross low current event in this normal light-emitting diode.
13. control methods according to claim 12, include:
This out-put supply of voltage stabilizing;
Detect this out-put supply whether one mistake high pressure event occurs;
When this crosses high pressure event generation, stop this out-put supply of voltage stabilizing; And
When this out-put supply reaches after this safety standard, recover this out-put supply of voltage stabilizing.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201110318282.6A CN103068093B (en) | 2011-10-19 | 2011-10-19 | Control method of light-emitting diode bunch |
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| CN201110318282.6A CN103068093B (en) | 2011-10-19 | 2011-10-19 | Control method of light-emitting diode bunch |
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| CN103068093B true CN103068093B (en) | 2014-12-03 |
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| CN104125694B (en) * | 2013-04-28 | 2016-08-24 | 深圳市海洋王照明工程有限公司 | The method of testing of LED drive power output short circuit protection defect and device |
| CN104902610B (en) * | 2014-03-04 | 2017-07-21 | 通嘉科技股份有限公司 | Dimming controlling method and related backlight controller |
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| US7411354B2 (en) * | 2006-12-20 | 2008-08-12 | Niko Semiconductor Co., Ltd. | Feedback and protection circuit of liquid crystal display panel backlight apparatus |
| TWI400989B (en) * | 2008-05-30 | 2013-07-01 | Green Solution Technology Inc | Light emitting diode driving circuit and controller thereof |
| CN201369862Y (en) * | 2009-02-04 | 2009-12-23 | 北京朗波尔光电科技有限公司 | LED constant current driver |
| CN101626655A (en) * | 2009-02-23 | 2010-01-13 | 陈炳桂 | High-pressure sodium lamp electronic energy converter |
| CN102003689B (en) * | 2009-09-02 | 2012-07-18 | 联咏科技股份有限公司 | Light-emitting diode device with function of simultaneously detecting open circuit and short circuit and method thereof |
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