CN103731951B - LED driving circuit and relevant driving method - Google Patents
LED driving circuit and relevant driving method Download PDFInfo
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- CN103731951B CN103731951B CN201210389104.7A CN201210389104A CN103731951B CN 103731951 B CN103731951 B CN 103731951B CN 201210389104 A CN201210389104 A CN 201210389104A CN 103731951 B CN103731951 B CN 103731951B
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B20/00—Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps
- Y02B20/40—Control techniques providing energy savings, e.g. smart controller or presence detection
Abstract
Embodiments of the invention disclose a kind of LED driving circuit and relevant driving method, in order to drive a LED strip.This drive circuit includes a current switch and a switch type power supplying device.This current switch is serially connected with between a driving power supply and an earth lead together with this LED strip.Foundation flows through a current signal of this LED strip, and this switch type power supplying device can set up this driving power supply, in order to stablize this current signal.This switch type power supplying device includes an enable end and a clamped circuit.An enable signal on this enable end can control this current switch.When a predeterminable event occurs, this enable signal of this clamped circuit strangulation is a logic of propositions value, so that this current switch maintains open circuit or turns on one of them.
Description
Technical field
The present invention relates to the drive circuit of light emitting diode.
Background technology
Because having good luminous efficiency, the component size simplified and permanent component life, light emitting diode is current
The most extensively illuminated or backlight industry is used.For example, the backlight in computer or telescreen, great majority are from biography
The CCFL backlight module of system, is converted into LED light module.
Fig. 1 shows the known LED driving circuit 10 that can be used in backlight module, in order to driven for emitting lights two pole
Pipe string 12.18 input power V of booster (booster)IN, it is converted into driving power supply VOUT.Light emitting diode string 12 and electric current
Switch 22 is serially connected with driving power supply VOUTAnd one between earth lead.Power-supply controller of electric 14 controls power switch 16, controls energy
Conversion.The groundwork of power-supply controller of electric 14, is stable feedback voltage V on feedback end FBFB, equivalent stabilizes and flows through
The electric current of LED strip 12, uses the brightness of stable LED strip 12.
Dim signal SDIMIt is couple to the enable end EN of power-supply controller of electric 14.Level shifting circuit 20 can be voltage level
Dim signal S for 5VDIM, it is converted into switching signal S that voltage level is 12VMOSDIM.As dim signal SDIMFor 5V, namely
During " 1 " in logic, current switch 22 turns on, power-supply controller of electric 14 power switched periodically switch 16, stablizes
(regulate) feedback voltage VFB, so light emitting diode string 12 stabilized illumination.
As dim signal SDIMFor 0V, during " 0 " the most in logic, current switch 22 cuts out as open circuit, power-supply controller of electric
14 close power switched switch 16, regularly so light emitting diode string 12 is the most luminous.
When designing LED driving circuit 10, need to consider many factors, for example LED open-circuit-protection, LED
Short-circuit protection, overvoltage protection, optical flare (flickering) etc..
In this specification, there is identical numbered elements or device, for having identical or similar functions, structure or spy
Property element or device, can learn with the tool teaching of this specification or deduce for people in the industry, but the most fully phase
With.For succinct reason, will not repeat specification.
Summary of the invention
Embodiments of the invention disclose a kind of LED driving circuit, in order to drive a LED strip.This drive circuit bag
Containing a current switch and a switch type power supplying device.This current switch is serially connected with a driving power supply together with this LED strip
And between an earth lead.Foundation flows through a current signal of this LED strip, and this switch type power supplying device can set up this driving electricity
Source, in order to stable (regulate) this current signal.This switch type power supplying device includes an enable end and strangulation electricity
Road.An enable signal on this enable end can control this current switch.When a predeterminable event occurs, this clamped circuit strangulation should
Enable signal is a logic of propositions value, so that this current switch maintains open circuit or turns on one of them.
Embodiments of the invention disclose a kind of driving method for a light emitting diode string, and this driving method includes:
Concatenate this light emitting diode string and this current switch between a driving power supply and is connected wires；According to flowing through the one of this LED strip
Current signal, sets up this driving power supply；This current switch is controlled with an enable signal；Detect whether a predeterminable event occurs；
And, when this predeterminable event occurs, this enable signal of strangulation is a logic of propositions value, to maintain this this current switch for open circuit
Or turn on one of them.
Accompanying drawing explanation
Fig. 1 shows the known LED driving circuit that can be used in backlight module.
Fig. 2 provides a circuit system, in order to the LED driving circuit of simulation drawing 1, LED short circuit phenomenon occurs.
Fig. 3 is a LED driving circuit implemented according to the present invention.
Fig. 4 shows a kind of sequential chart implemented according to the present invention.
Fig. 5 is another LED driving circuit implemented according to the present invention.
Fig. 6 A and Fig. 6 B shows two kinds of sequential charts respectively.
Fig. 7 is the power-supply controller of electric implemented according to the present invention.
[main element symbol description]
10 LED driving circuit
12 light emitting diode strings
14 power-supply controller of electric
16 power switch
18 boosters
20 level shifting circuits
22 current switches
24 short switches
26 resistance
30 LED driving circuit
32 switch type power supplying devices
34 light adjusting controllers
36 power-supply controller of electric
37 agitators
38 resistance
39 boost control circuits
40 comparators
42 set-reset flip-floops
44 strangulation switches
46 timers
80 LED driving circuit
82 switch type power supplying devices
83 power-supply controller of electric
84 enable clamped circuits
86 pulse generators
88 strangulation switches
92 power-supply controller of electric
93 LED short-circuit protection circuits
DIM dims end
EN enable end
FB feedback end
SDIMDim signal
SDRVPulse width modulating signal
SENEnable signal
SFaultRub-out signal
SLEDSHTShort-circuit signal
SMOSDIMSwitching signal
SPDPower save signal
SPLS Pulse
TMIN-ONThe shortest enable time
TOUTExceed the time limit the time
t0、t1、t2、t3、t4、t5、t6Time
VFBFeedback voltage
VINInput power
VOUTDrive power supply
Detailed description of the invention
Fig. 2 provides a circuit system, in order to the LED driving circuit 10 of simulation drawing 1, LED short circuit phenomenon occurs.Phase
A short switch 24 is added compared with Fig. 1, Fig. 2, in parallel with LED strip 12.As described in prior art, when light modulation letter
Number SDIMDuring for " 1 " in logic, current switch 22 turns on, the power switched switch 16 in power-supply controller of electric 14 cycle.Now, one
Denier short switch 24 suddenly-applied short circuit (be used for simulate LED strip 12 be short-circuited event), feedback voltage VFBPower supply can be output suddenly
VOUTAffecting and rapid increase, it is special that its voltage results may be up to 1 hectovolt.Now, without LED short-circuit protection, power supply controls
Device 14 is by because bearing the feedback voltage V of supertensionFBAnd damage Fire Overheat；Being similar to, the most substantial amounts of electric current will flow through electricity
Stream switch 22 and resistance 26, it is also possible to produce the risk of Fire Overheat.
Fig. 3 is a LED driving circuit 30 implemented according to the present invention, in order to drive LED strip 12.Luminous two
Pole tube drive circuit 30 has the function of LED short-circuit protection.LED driving circuit 30 includes switch type power supplying
Device 32, light adjusting controller 34 and current switch 22.
Light adjusting controller 34 includes resistance 38 and level shifting circuit 20.Resistance 38 is connected to dim end DIM and electricity
Between the enable end EN of source controller 36, and level shifting circuit 20 be connected to enable end EN and current switch 22 control end it
Between.When power-supply controller of electric 36 does not drive enable end EN, namely making enable end EN is high input impedance (high input
Impedance), time, logical value is the dim signal S of " 1 "DIMThe switch power switch 16 in power-supply controller of electric 36 cycle can be made
Set up and drive power supply VOUT, and conducting current switch 22；Logical value is the dim signal S of " 0 "DIMPower-supply controller of electric 36 can be made solid
Surely close power switch 16, stop setting up driving power supply VOUT, and make current switch 22 open a way.
But, enable end EN can be driven when some condition according to the implemented power-supply controller of electric of the present invention 36, force
Enable signal S on enable end ENENLogical value.When enable end EN is driven by power-supply controller of electric 36, open for controlling electric current
Close 22 speeches, because there being the existence of resistance 38, so enable signal SENRelative to dim signal SDIMCan there is higher priority.
In other words, when enable end EN is driven by power-supply controller of electric 36, current switch 22 is controlled by power-supply controller of electric 36, and enable
Signal SENLogical value can be with dim signal SDIMDifferent.When the enable end EN of power-supply controller of electric 36 is high input impedance, electricity
Stream switch 22 is by dim signal SDIMControlled, enable signal SENSubstantially follow dim signal SDIM, substantially have identical logical value.
In one embodiment, as enable signal SENDuring for " 1 " in logic, power-supply controller of electric 36 produces at drive end DRV
One pulse width modulating signal SDRV, carry out the power switch 16 in periodic on-off control booster 18, in order to set up driving electricity
Source VOUT, and stablize the feedback voltage V on feedback end FBFB.For example, it is desirable to by feedback voltage VFBStable at 0.3V, reach
To the purpose determining electric current driving LED strip 12.Meanwhile, it is the enable signal S of " 1 " in logicENThrough level shifting circuit 20, permissible
Current switch 22 is made to turn on.
As enable signal SENDuring for " 0 " in logic, power-supply controller of electric 36 is fixing makes the pulse width on drive end DRV adjust
Signal S processedDRVFor " 0 " in logic, close power switch 16, stop setting up driving power supply VOUT.It is the enable letter of " 0 " in logic
Number SENThrough the level conversion (level shifting) that level shifting circuit 20 is provided, become switching signal SMOSDIM, permissible
Current switch 22 is made to close.
Power-supply controller of electric 36 includes a boost control circuit 39, comparator 40, set-reset flip-floop 42, strangulation switch 44,
And timer 46.Comparator 40, set-reset flip-floop 42, strangulation switch 44 and timer 46 constitute a LED short-circuit protection electricity
Road.
Comparator 40 detects feedback voltage VFB.Feedback voltage VFBEquivalent flows through a current signal of light emitting diode string 12.
When normal operating, feedback voltage VFBShould be about stable at 0.3V, less than 0.5V, so comparator 40 is output as in logic
" 0 ", the Q output of set-reset flip-floop 42 also be " 0 " in logic, and it is open-circuit condition that strangulation switchs 44.Now, enable signal SENCan
With with dim signal SDIMThere is identical logical value.
Once LED strip 12 there occurs short circuit event, feedback voltage VFBCan rise rapidly from 0.3V.At feedback voltage
VFBDuring higher than 0.5V, rub-out signal S of set-reset flip-floop 42 outputFaultBeing configured to " 1 " in logic, strangulation switch 44 will cause
Can signal SENStrangulation " 0 " logically, and not by dim signal SDIMAffected.Similar previously described, be in logic " 0 "
Enable signal SENPower switch 16 will be closed by boost control circuit 39, and close electric current by level shifting circuit 20 and open
Close 22.Now, because flowing through the current reduction of resistance 26, so feedback voltage VFBBegin to decline, too high electricity can be avoided
The feedback voltage V of pressureFBDamage power-supply controller of electric 36, reach LED short-circuit protection.
The closedown of current switch 22, will make feedback voltage VFBDrop below 0.5V.Now because of rub-out signal SFaultAlso
It is maintained at " 1 " in logic, enable signal SENStill strangulation " 0 " logically, so LED short-circuit protection will not release.
Power-supply controller of electric 36 can periodically release LED short-circuit protection, suspends strangulation enable signal SEN.Timer 46 from
Enable signal SENTiming is started when being changed into " 0 " in logic.When timer 46 finds to stop setting up to drive power supply VOUTMore than one
Exceed the time limit time TOUTAfter length, power save signal S that timer 46 is exportedPDCan be " 1 " from " 0 " transition, reset set-reset flip-floop 42,
Make rub-out signal SFaultBecome " 0 " in logic, strangulation switch 44 no longer strangulation enable signal SEN.Now, enable signal SENCan
To start to follow dim signal SDIM-.If now dim signal SDIM-For " 1 " in logic, and LED short circuit event is not the most arranged
Remove, then enable signal SENAfter becoming " 1 " in logic, power save signal SPDTo be " 0 " from " 1 " transition at once, feedback voltage VFBFrom
0V is because LED short circuit event is not yet got rid of so beginning to ramp up.Once exceed feedback voltage VFBDuring higher than 0.5V, can make once again again
Strangulation switchs 44 strangulation enable signal SENIn " 0 " in logic, perform LED short-circuit protection.So, power-supply controller of electric 36 can week
Phase property ground releases and enters LED short-circuit protection.Once LED short circuit event has been got rid of, and resets set-reset flip-floop 42 at timer 46,
After releasing LED short-circuit protection, power-supply controller of electric 36 just can be along with dim signal SDIM-, revert to normal operating.
Fig. 4 shows a kind of sequential chart implemented according to the present invention, wherein, from top to bottom, is sequentially dim signal SDIM、
Enable signal SEN, feedback voltage VFB, control short switch 24 short-circuit signal SLEDSHT, rub-out signal SFAULT, at current switch
22 switching signals S controlling endMOSDIM, pulse width modulating signal S on drive end DRVDRV, and power save signal SPD。
Please also refer to Fig. 3 and Fig. 4.At time t0, dim signal SDIM" 1 " is changed into from " 0 ", so pulse width modulation
Signal SDRVStart power switch 16, switching signal S are periodically switchedMOSDIMCurrent switch 22 is made to turn on, feedback voltage VFBPast
0.3V is close.
At time t1, short-circuit signal SLEDSHTChanging into " 1 " from " 0 ", simulation LED short circuit event occurs, so feedback voltage VFB
From 0.3V rapid increase.
At time t2, feedback voltage VFBArrive at the LED short-circuit protection trigger voltage of 0.5V.As described above, SR
Rub-out signal S of trigger 42 outputFAULT" 1 " is changed into, enable signal S from " 0 "ENStrangulation is in " 0 ", so result in pulse
Bandwidth modulation signals SDRVAnd switching signal SMOSDIMAll it is fixed on " 0 " in logic.Now, timer 46 starts timing.Cause
For the open circuit of current switch 22, so feedback voltage VFBBegin to decline.
At time t3, enable signal S learnt by timer 46ENThe time T that exceeds the time limit is had been in the time of " 0 "OUT, also
It it is exactly LED short-circuit protection overtime.Therefore, power save signal SPDReset rub-out signal SFAULT, relieve LED short-circuit protection.This
Time, enable signal SENStart to follow dim signal SDIM.Because LED short circuit event does not the most get rid of (short-circuit signal SLEDSHTFor
" 1 "), so feedback voltage VFBRapid increase.
Such as time t2Occurred, at time t4, feedback voltage VFBExceed again 0.5V, the most again touch LED short
Road is protected.So, as long as LED short circuit event is not got rid of, power-supply controller of electric 36 can periodically release and enter LED short circuit and protect
Protect.
At time t5, LED short circuit event has got rid of (short-circuit signal SLEDSHTChange into " 0 ").Now, because timer 46
The most do not find LED short-circuit protection overtime, so LED short-circuit protection releases the most at once.Timer 46 is at time t6Find
LED short-circuit protection overtime, so returning to similar time t1Normal operating before.
As shown in Figure 3, power-supply controller of electric 36 can include an agitator 37, in order to determine that pulse width modulation is believed
Number SDRVSwitch periods and release LED short-circuit protection overtime the time T that exceeds the time limitOUT.For example, agitator 37 determines pulse
Bandwidth modulation signals SDRVSwitch periods be 33 microseconds (us), and the time T that exceeds the time limitOUTIt is 10000 switch periods.
As enable signal SENWhen " 0 " transition logically is " 1 ", pulse width produced by boost control circuit 39 is adjusted
Signal S processedDRV, can be according to feedback voltage VFB, with switch periods, start periodic switch power switch 16 at once.Such as the time
t0To t1Period shown in.As enable signal SENWhen " 1 " transition the most logically is " 0 ", pulse width modulating signal SDRVVertical
I.e. close power switch 16, such as time t2To t3Period shown in.If enable signal SENRest on " 0 " in logic the most long
, exceed the time T that exceeds the time limitOUT, this may mean dim signal SDIM-It it is exactly to maintain " 0 " for a long time, it is undesirable to LED strip 12
Luminous.Now, in order to save electric energy, logic is power save signal S of " 1 "PDPower-supply controller of electric 36 can be made to operate in a power saving mould
Formula.For example, in a power-save mode, pulse width modulating signal SDRVFor " 0 ", the agitator 37 in power-supply controller of electric 36 closes
Close (stopping oscillation), to save electric energy loss.
From described above it is found that the LED driving circuit 30 implemented according to the present invention, there is a following characteristics:
1.LED short-circuit protection: when LED short circuit event occurs, power-supply controller of electric 36 can in time close Power convert,
And prevent extraneous too high feedback voltage VFBDamage oneself.
2. periodically suspend LED short-circuit protection: during LED short-circuit protection overtime, power-supply controller of electric 36 no longer strangulation enable
Signal SENIn " 0 " in logic.As long as LED short circuit event is excluded, LED driving circuit 30 can be along with light modulation
Signal SDIMControl, make to normal operating light emitting diode string 12 luminous,.
3. battery saving mode operation: as dim signal SDIMWhen making light emitting diode string 12 the most luminous for a long time, power-supply controller of electric
36 can enter the battery saving mode operation than less power consumption.
The prior art of Fig. 1 separately has a potential problem: optical flare (flickering).For stiffness of system and
The consideration of handoff loss, the system response frequency range of LED driving circuit 10 can not be the highest, typically may design 100 ~
Near 300KHz.So system response frequency range also determines the system response shortest time.Once dim signal SDIMIn, logic
Value is the fluorescent lifetime (Dim-On time) when 1, shorter than what that system response shortest time also came, and that light emitting diode drives
Circuit 10 because of having little time reaction, and will cause the electric current flowing through LED strip 12 unstable, it is possible to create can experience on naked eyes
Optical flare.This phenomenon is not allowed by system or accepts.
Fig. 5 is a LED driving circuit 80 implemented according to the present invention, in order to drive LED strip 12, wherein,
Power-supply controller of electric 83 in switch type power supplying device 82 can make LED strip 12 have fluorescent lifetime (the Minimum On of minimum
Time), to avoid optical flare.
Power-supply controller of electric 83 includes an enable clamped circuit 84, and it has the pulse generator that a rising edge triggers
(pulse generator) 86 and strangulation switch 88.As enable signal SENOccur that (" 0 " in logic changes into rising edge
" 1 "), it is the shortest enable time T that the pulse generator 86 that rising edge triggers just produces time spanMIN-ONPulse (pulse)
SPLS.Pulse SPLSDuring appearance, strangulation switch 88 can be enable signal SENStrangulation " 1 " logically so that it is not by dim signal
SDIMImpact, fixing conducting current switch 22.Pulse SPLSAfter disappearance, strangulation switch 88 will not strangulation enable signal SENSo that it is
Dim signal S can be followedDIM。
Fig. 6 A and Fig. 6 B shows two kinds of sequential charts respectively.In Fig. 6 A and Fig. 6 B, from top to bottom, the tune being sequentially in Fig. 5
Optical signal SDIM, pulse SPLS, and enable signal SEN.In fig. 6, although dim signal SDIMFluorescent lifetime less than the shortest cause
Can time TMIN-ON, but because the strangulation of strangulation switch 88, so enable signal SENTime for " 1 " in logic is about arteries and veins
Rush SPLSDefined in the shortest enable time TMIN-ON.In Fig. 6 B, dim signal SDIMWith enable signal SENFor " 1 " in logic
Time is approximately equivalent, both greater than pulse SPLSDefined in the shortest enable time TMIN-ON.Knowable to Fig. 6 A and Fig. 6 B, in Fig. 5,
The fluorescent lifetime of LED strip 12 is the shortest enable time T to I haven't seen you for agesMIN-ON.So, just may can solve in known technology, be sent out
Raw optical flare problem.
In one embodiment, the shortest enable time TMIN-ONCan be 2 or 3 pulse width modulating signal SDRVSwitch week
Phase.In other words, the shortest enable time TMIN-ONDetermined by agitator 37.
LED short-circuit protection in Fig. 3 and the shortest enable time T in Fig. 5MIN-ON, a power supply can be implemented in simultaneously
Controller, as shown in Figure 7.In certain embodiments, the power-supply controller of electric 36 in the power-supply controller of electric 92 replacement Fig. 3 in Fig. 7.
Power-supply controller of electric 92 includes enable clamped circuit 84 and LED short-circuit protection circuit 93.In the figure 7, agitator 37 is associated with
Pulse width modulating signal SDRVSwitch periods, the time T that exceeds the time limit of LED short-circuit protection overtimeOUT, and the shortest enable time
TMIN-ON。
The operation of enable clamped circuit 84 and LED short-circuit protection circuit 93 and principle, relevant in Fig. 3 to Fig. 5
Illustrate to be explained, for succinct reason, no longer repeat.
The foregoing is only the preferred embodiments of the present invention, all equalizations done according to claims of the present invention change and repair
Decorations, all should belong to the covering scope of the present invention.
Claims (23)
1. a LED driving circuit, in order to drive a LED strip (string), this drive circuit includes:
One current switch, is serially connected with between a driving power supply and an earth lead together with this LED strip；And
One switch type power supplying device, foundation flows through a current signal of this LED strip, sets up this driving power supply, in order to stable
(regulate) this current signal, this switch type power supplying device includes an enable end and a clamped circuit；
Wherein, the enable signal on this enable end can control this current switch；And
When a predeterminable event occurs, this enable signal of this clamped circuit strangulation is a logic of propositions value, so that this current switch
Maintain open circuit or turn on one of them.
2. LED driving circuit as claimed in claim 1, wherein, this predeterminable event is that this current signal is pre-more than one
If value；When this predeterminable event occurs, this enable signal of this clamped circuit strangulation, in a forbidden energy logical value, makes this current switch open
Road, to provide light emitting diode short-circuit protection.
3. LED driving circuit as claimed in claim 2, wherein, this switch type power supplying device periodically stops
This enable signal of strangulation is in this forbidden energy logical value.
4. LED driving circuit as claimed in claim 2, wherein, this switch type power supplying device also includes a meter
Time device, stay in the forbidden energy time of this forbidden energy logical value in order to calculate this enable signal.
5. LED driving circuit as claimed in claim 4, wherein, when this forbidden energy time more than the overtime time time,
This timer provides a power save signal, to stop this enable signal of strangulation in this forbidden energy logical value.
6. LED driving circuit as claimed in claim 5, wherein, this power save signal can make this switch type power supplying
Device enters a battery saving mode.
7. LED driving circuit as claimed in claim 5, wherein, this switch type power supplying device also includes and shakes
Swinging device, in order to determine a switch periods, this overtime time is these switch periods several.
8. LED driving circuit as claimed in claim 1, wherein, this predeterminable event is that this enable signal produces on one
Rise edge；When this predeterminable event occurs, this enable signal of this clamped circuit strangulation, in an enable logical value, maintains this electricity of unlatching
Stream switch.
9. LED driving circuit as claimed in claim 8, wherein, the shortest enable after this predeterminable event occurs
Time, this enable signal of this clamped circuit strangulation is in this enable logical value, so that this LED strip has the shortest fluorescent lifetime.
10. LED driving circuit as claimed in claim 1, wherein, when this enable signal is a forbidden energy logical value,
This switch type power supplying device stops setting up this driving power supply；When this enable signal is an enable logical value, this switching regulator electricity
Source supply sets up this driving power supply.
11. LED driving circuit as claimed in claim 10, wherein, when this enable signal is that this forbidden energy logical value reaches
After one overtime time, this switch type power supplying device enters a battery saving mode.
12. LED driving circuit as claimed in claim 1, wherein, this switch type power supplying device includes one liter
Depressor.
13. LED driving circuit as claimed in claim 1, also include:
One resistance, is coupled between a light modulation end and this enable end；And
One level shifting circuit, is coupled between this current switch and this enable end；
Wherein, this light modulation end can receive a dim signal, in order to control this current switch.
14. 1 kinds of driving methods for a light emitting diode string, this driving method includes:
Concatenate this light emitting diode string and current switch between a driving power supply and is connected wires；
Foundation flows through a current signal of LED strip, sets up this driving power supply；
This current switch is controlled with an enable signal；
Detect whether a predeterminable event occurs；And
When this predeterminable event occurs, this enable signal of strangulation is a logic of propositions value, to maintain this this current switch for open circuit
Or turn on one of them.
15. driving methods as claimed in claim 14, this predeterminable event is that this current signal is more than a preset value, this driving side
Method also includes:
When this predeterminable event occurs, this enable signal of strangulation is a forbidden energy logical value, so that this current switch is open circuit, to carry
For light emitting diode short-circuit protection.
16. driving methods as claimed in claim 15, also include:
Calculate this enable signal and stay in the forbidden energy time of this forbidden energy logical value；And
When this forbidden energy time more than the overtime time time, suspend this enable signal of strangulation in this forbidden energy logical value.
17. driving methods as claimed in claim 16, also include:
When this forbidden energy time exceedes this overtime time, a switch type power supplying device is made to enter a battery saving mode.
18. driving methods as claimed in claim 16, also include:
One switch type power supplying device is provided, there is a switch periods, set up this driving power supply；
Wherein, this overtime time is this switch periods of integral multiple.
19. driving methods as claimed in claim 14, also include:
This current switch is controlled according to a dim signal；And
This enable signal is made to have higher priority compared with this dim signal.
20. driving methods as claimed in claim 19, also include:
Coupling a resistance and dim between end and an enable end in one, wherein, this dim signal is positioned at this light modulation end, and this enable is believed
Number it is positioned at this enable end；And
This enable signal of level conversion, to become a switching signal, controls this current switch.
21. driving methods as claimed in claim 14, wherein, this predeterminable event is that this enable signal produces a rising edge, should
Driving method also includes:
When this predeterminable event occurs, this enable signal of strangulation, in an enable logical value, maintains this current switch of unlatching.
22. driving methods as claimed in claim 21, include:
In the shortest enable time after this predeterminable event occurs, this enable signal of strangulation is in this enable logical value, so that being somebody's turn to do
LED strip has the shortest fluorescent lifetime；And
After this shortest enable time, stop this enable signal of strangulation in this enable logical value.
23. driving methods as claimed in claim 22, include:
One switch type power supplying device is provided, there is a switch periods, set up this driving power supply；
Wherein, this shortest enable time is these switch periods several.
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| CN201210389104.7A CN103731951B (en) | 2012-10-15 | 2012-10-15 | LED driving circuit and relevant driving method |
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|---|---|---|---|
| CN201210389104.7A CN103731951B (en) | 2012-10-15 | 2012-10-15 | LED driving circuit and relevant driving method |
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| CN103731951B true CN103731951B (en) | 2016-09-21 |
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| DE102016107578B4 (en) * | 2016-04-25 | 2023-06-01 | Vossloh-Schwabe Deutschland Gmbh | Operating circuit and method for operating at least one light source |
| JP6805808B2 (en) * | 2016-12-26 | 2020-12-23 | セイコーエプソン株式会社 | Light emission control circuit, light source device, and electronic equipment |
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| CN102548121A (en) * | 2010-12-06 | 2012-07-04 | 通嘉科技股份有限公司 | Integrated circuit, control method and light source providing system |
| CN102685971A (en) * | 2011-03-08 | 2012-09-19 | 登丰微电子股份有限公司 | Conversion controller |
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| JP5175427B2 (en) * | 2005-05-31 | 2013-04-03 | Ｎｅｃディスプレイソリューションズ株式会社 | Light emitting element driving device |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101730329A (en) * | 2008-10-10 | 2010-06-09 | 华映视讯（吴江）有限公司 | Back light module control system and control method thereof |
| CN102208867A (en) * | 2010-06-11 | 2011-10-05 | 崇贸科技股份有限公司 | Starting circuit with low standby power consumption for power converter |
| CN102548121A (en) * | 2010-12-06 | 2012-07-04 | 通嘉科技股份有限公司 | Integrated circuit, control method and light source providing system |
| CN102685971A (en) * | 2011-03-08 | 2012-09-19 | 登丰微电子股份有限公司 | Conversion controller |
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