CN105338683B - LED driving circuit - Google Patents
LED driving circuit Download PDFInfo
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- CN105338683B CN105338683B CN201410386129.0A CN201410386129A CN105338683B CN 105338683 B CN105338683 B CN 105338683B CN 201410386129 A CN201410386129 A CN 201410386129A CN 105338683 B CN105338683 B CN 105338683B
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Abstract
LED driving circuit includes a voltage source, multiple current control circuits, at least a 3rd resistor and an at least transmission gate.One voltage source is providing an input voltage.Each current control circuit includes a first switch, a comparator, a first resistor and a second resistance.The first switch is coupled to corresponding one group of light emitting diode.The comparator is coupled to a corresponding reference voltage and the switch.The first resistor is coupled to the comparator and the first switch, which is coupled to the first switch and a common reference voltage.The 3rd resistor is coupled to the first switch of the current control circuit in multiple current control circuit, and the transmission gate is coupled between the comparator of another current control circuit in the 3rd resistor and multiple current control circuit.
Description
Technical field
The present invention relates to a kind of LED driving circuits more particularly to a kind of improving the hair of current stability
Optical diode driving circuit.
Background technology
In order to energy saving, using light emitting diode (light emitting diode, LED) light-emitting device
It is more and more universal.In general, light-emitting diode assembly includes multiple light emitting diodes, to provide required light emission luminance.It is more
The setting that a light emitting diode may be used and connect or concatenate, or both mixing setting, regardless of make which kind of setting, to hair
For optical diode device, correct voltage and/or electric current are provided to light emitting diode for being in the operation of light emitting diode
It is considerable.
However, existing LED driving circuit and stable electric current can not be provided, referring to FIG. 1, Fig. 1 is public
Know the schematic diagram of the LED driving circuit of technology.As shown in Figure 1, LED driving circuit 100 includes multigroup hair
Optical diode (such as two groups of light emitting diodes 11,12, wherein each group of light emitting diode can have one or more concatenations
Light emitting diode) and multiple current control circuits (such as two current control circuits 20,30).Current control circuit 20,30
It is respectively coupled to multi-group light-emitting diode 11,12, wherein current control circuit 20 includes comparator 22, transistor T1, crystal
Pipe T3 and multiple resistance (such as first resistor R1, second resistance R2), and current control circuit 30 includes comparator 32, crystalline substance
Body pipe T2, transistor T4 and multiple resistance (such as first resistor R1, second resistance R2).The positive input terminal (+) of comparator 22
It is coupled to a reference voltage Vref, wherein transistor T3 and transistor T4 are controlled by the second voltage source VCC2.First, when
The input voltage that one voltage source VCC1 is provided is more than the cross-pressure VF1 but not greater than two groups of hairs of first group of light emitting diode 11
When the cross-pressure VF1+VF2 that optical diode 11,12 is added, electric current can only firstly flow through first group of light emitting diode 11.Then, when
The input voltage that one voltage source VCC1 is provided becomes larger, and the cross-pressure VF1+ being added more than two groups of light emitting diodes 11,12
When VF2, electric current flows through second group of light emitting diode 12 at this time so that the voltage of A points rises, and then leads to the voltage of B points
Decline.When the voltage of B points deteriorates to less than the critical value of transistor T1, transistor T1 will be closed.At this point, flowing through second
The electric current of group light emitting diode 12 can be equal to the electric current for flowing through transistor T2, as：I=β (Vgs-Vt) 2, wherein I is to flow through
The size of current of second group of light emitting diode 12, β are process parameters, and Vgs is the grid-source voltage of transistor T2, and Vt is
Threshold voltage (threshold voltage).The transistor to be dispatched from the factory due to every can have different threshold voltages, can not
It accurately learns under transistor characteristic in advance, causes known LED driving circuit that can not provide light emitting diode steady
Constant current.
Invention content
Therefore, luminous the two of stabling current can be provided light emitting diode one of the objects of the present invention is to provide a kind of
Pole pipe driving circuit, to solve the above problems.
One embodiment of the invention provides a kind of light emitting diode (light emitting diode, LED) driving electricity
Road, the LED driving circuit include a first voltage source, multiple current control circuits, an at least 3rd resistor and
An at least transmission gate (transmission gate, TG).The first voltage source is coupled to multigroup LED of concatenation, to provide
One input voltage.Multiple current control circuit is respectively coupled to multigroup LED, and each current control circuit includes one first
Switch, a comparator, a first resistor and a second resistance.The first switch includes a first end, a control terminal and one
The first end of second end, the first switch is coupled to corresponding one group of LED.The comparator includes a positive input terminal, one
The positive input terminal of negative input end and an output end, the comparator is coupled to a corresponding reference voltage, which is somebody's turn to do
Output end is coupled to the control terminal of the first switch.The first resistor is coupled to the negative input end of the comparator and is somebody's turn to do
Between the second end of first switch, which is coupled to second end and collective reference electricity of the first switch
Between pressure.The first end of an at least 3rd resistor is coupled to the current control circuit in multiple current control circuit
The second end of the first switch, and an at least transmission gate be coupled to this at least the second end of a 3rd resistor with it is multiple
Between the negative input end of the comparator of another current control circuit in current control circuit, wherein when at least one biography
When defeated door is switched on, the second end of the first resistor of another current control circuit is coupled directly to an at least third
The first end of resistance, when an at least transmission gate is closed (turned off), another current control circuit this
It is open circuit between the second end of one resistance and the first end of an at least 3rd resistor.
Another embodiment of the present invention provides a kind of LED driving circuit, the LED driving circuit
Including a first voltage source, multiple current control circuits and a second resistance.The first voltage source is coupled to the multigroup of concatenation
LED, to provide an input voltage.Multiple current control circuit is respectively coupled to multigroup LED, each current control electricity
Road includes a first switch, a comparator and a first resistor.The first switch include a first end, a control terminal and
The first end of one second end, the first switch is coupled to corresponding one group of LED.The comparator includes a positive input terminal, one
The positive input terminal of negative input end and an output end, the comparator is coupled to a corresponding reference voltage, the comparator
The output end is coupled to the control terminal of the first switch.The first resistor be coupled to the comparator the negative input end and
Between the second end of the first switch.The second resistance be coupled to the first switch of each current control circuit this
Between two ends and a common reference voltage.An at least current control circuit additionally comprises one in multiple current control circuit
Three resistance are coupled at least negative input end of the comparator of a current control circuit and another current control circuit
The first switch the first end between.
In conclusion setting through the embodiment of the present invention, LED driving circuit can provide LED stabilizations according to this
Electric current, and do not influenced by the variation on LED processing procedures, and then promote the operation efficiency of LED.In addition, the present invention more provides
A kind of light adjusting framework can allow the LED driving circuit to improve its luminous stability, and then makes luminous two
What pole pipe driving circuit can be stablized in dimming process shines, and has showing Suddenly it apperared and disappered without having light in known technology
As.
Description of the drawings
Fig. 1 is the schematic diagram of the LED driving circuit of known technology.
Fig. 2 is the schematic diagram of the first embodiment of LED driving circuit of the present invention.
Fig. 3 is the equivalent circuit diagram of LED driving circuit shown in Fig. 2.
Fig. 4 is the schematic diagram of the second embodiment of LED driving circuit of the present invention.
Fig. 5 is that the positive input terminal of multiple comparators of multiple current control circuits in Fig. 4 is respectively coupled to different references
The current-vs-time figure of the LED driving circuit of voltage.
Fig. 6 is that the positive input terminal of multiple comparators of multiple current control circuits in Fig. 4 is coupled to same reference voltage
The current-vs-time figure of LED driving circuit.
Fig. 7 is the schematic diagram of the 3rd embodiment of LED driving circuit of the present invention.
Fig. 8 is the schematic diagram of the fourth embodiment of LED driving circuit of the present invention.
【The simple declaration of reference numeral】：
200 LED driving circuits
230_1,230_2 light emitting diode
210,220 current control circuit
CR comparators
R1 first resistors
R2 second resistances
R3 3rd resistors
Vref1, Vref2 reference voltage
VX, VY voltage
VF1, VF2, VF3, VF4 cross-pressure
I1, I2 electric current
VCC1 first voltage sources
VCC2 the second voltage sources
Vin input voltages
SW1 first switches
SW2 second switches
TG1 transmission gates
Specific implementation mode
Some vocabulary has been used in specification and subsequent claim to censure specific element.It is affiliated
Has usually intellectual in field, it is to be appreciated that hardware manufacturer may call same element with different nouns.This
Specification and subsequent claim are existed not in such a way that the difference of title is used as and distinguishes element with element
Difference functionally is used as the criterion of differentiation.In the "comprising" of specification in the whole text and subsequent claim mentioned in
It is an open term, therefore should be construed to " including but not limited to ".In addition, " coupling " word includes any direct herein
And indirect electrical connection.Therefore, if it is described herein that a first device is coupled to a second device, then represent this first
Device can directly be electrically connected in the second device, or by other devices or connection means be electrically connected indirectly to this
Two devices.
Referring to FIG. 2, Fig. 2 is the schematic diagram of the first embodiment of LED driving circuit of the present invention.Such as Fig. 2 institutes
Show, LED driving circuit 200 includes a first voltage source VCC1 and multiple current control circuits (such as two electricity
Flow control circuit 210,220).First voltage source VCC1 is coupled to multi-group light-emitting diode (such as two groups of light-emitting diodes of concatenation
Pipe 230_1,230_2, and according to actual circuit requirements, each group of light emitting diode may include one or multiple concatenations
Light emitting diode, in other words, the present invention does not limit to the light emitting diode number of each group of light emitting diode), to provide
One input voltage vin, wherein first voltage source VCC1 can pass through a bridge rectifier and carry out rectification.
Note that do not influencing the technology of the present invention disclose under, Fig. 2 only illustrate two current control circuits 210,220 and
Two groups of light emitting diodes 230_1,230_2, however, in fact, LED driving circuit 200 may include N group light-emitting diodes
Pipe and N number of current control circuit, wherein the N group light emitting diodes concatenate, and first group of light emitting diode can connect first voltage
Source VCC1 receives input voltage, and is connected to a current control circuit 220, the 2nd group of light emitting diode to (N-1) group
Light emitting diode can be separately connected (N-2) a current control circuit 220, and N groups light emitting diode (that is, last group hair
Optical diode) it is then connected to current control circuit 230, in other words, (N-1) a current control circuit 220 and a current control
Circuit 230 can concatenate, to control the electric current for flowing through the N group light emitting diodes respectively.
Current control circuit 210,220 is respectively coupled to two groups of light emitting diodes 230_1,230_2 (in the present embodiment, often
One group of light emitting diode is used as example explanation with a light emitting diode), and each current control circuit 210,220 includes
One first switch SW1, a second switch SW2, a comparator CR, a first resistor R1 and a second resistance R2.First switch
SW1 and second switch SW2 include a first end, a control terminal and a second end, first switch SW1 and second switch
SW2 can be transistor unit, but the present invention is not limited thereto.
Second switch SW2 includes a first end, a control terminal and a second end.The first end of second switch SW2 couples
It is coupled to a second voltage source VCC2 in the control terminal of corresponding one group of light emitting diode, second switch SW2, and second opens
The second end for closing SW2 is coupled to the first end of first switch SW1.The second voltage source VCC2 is controlling opening for second switch SW2
It opens (conducting) and closes (being not turned on).When LED driving circuit 200 is run, second switch SW2 can be because of the second electricity
Bias that potential source VCC2 is provided and open, and the first end of first switch SW1 is coupled to corresponding one group of light-emitting diodes
Pipe, for example, the first end of the first switch SW1 of current control circuit 210 is coupled to first group of light emitting diode 230_1, and electricity
The first end of the first switch SW1 of flow control circuit 220 is coupled to second group of light emitting diode 230_2.However, the present invention is not
It is limited to this, in the present embodiment and subsequent embodiment, second switch SW2 can be omitted according to actual design demand.Comparator
(operational amplifier) CR includes a positive input terminal (+), a negative input end (-) and an output end, and comparator CR's is just defeated
Enter end and be coupled to a corresponding reference voltage, for example, the positive input terminal of the comparator CR of current control circuit 210 is coupled to ginseng
Voltage Vref1 is examined, and the positive input terminal of the comparator CR of current control circuit 220 is coupled to reference voltage Vref 2.In addition, than
Output end compared with device CR is coupled to the control terminal of first switch SW1.In the present embodiment, reference voltage Vref 1, Vref2 can be set
It is set to identical or different, also namely based on considering in design, the comparator CR of multiple current control circuits 210,220 is just
Input terminal can be respectively coupled to different reference voltages or same reference voltage.
First resistor R1 is coupled between the negative input end of comparator CR and the second end of first switch SW1, the second electricity
Resistance R2 is coupled between the second end and a common reference voltage of first switch SW1, for example, collective reference voltage can
E.g. ground voltage, but the present invention is not limited thereto.
In multiple current control circuits possessed by LED driving circuit 200, each two current control circuit
An a 3rd resistor R3 and transmission gate (transmission is coupled between (such as current control circuit 210,220)
gate,TG)TG1.The first end of 3rd resistor R3 is coupled to the of a current control circuit (such as current control circuit 210)
The second end of one switch SW1, transmission gate TG1 are coupled to the second end of 3rd resistor R3 and another current control circuit (such as electricity
Flow control circuit 220) comparator CR negative input end between.In the present embodiment, first resistor R1 and 3rd resistor R3
It is kilohm (k ohm) grade and second resistance R2 is ohm (ohm) grade, but invention is not limited thereto.It note that when hair
In optical diode driving circuit 200 have multiple transmission gate TG when (that is, LED driving circuit 200 include two with
On current control circuit), multiple transmission gate TG1 can be individually switched on one by one.For example, when transmission gate TG1 is to lead
When logical, the second end of the first resistor R1 of current control circuit 210 can be coupled directly to the second end of 3rd resistor R3, and work as
When an at least transmission gate is closed (turned off), the second end and third of the first resistor R1 of current control circuit 210
It is open circuit between the second end of resistance R3.That is, when transmission gate TG1 is connected, it can be to current control circuit 210,220
Being associated property operates, and when transmission gate TG1 is closed, independent operation can be respectively carried out to current control circuit 210,220.
In current control circuit 210, the voltage VX of the second end of switch SW1 will be equal to reference voltage Vref 1, because
This electric current I1 for flowing through second resistance R2 can be equal to the voltage value of reference voltage Vref 1 divided by the resistance value of second resistance R2, that is,
As shown in (1) formula：
In current control circuit 220, the calculation of the electric current I2 of second resistance R2 is flowed through please also refer to Fig. 3, figure
3 be the equivalent circuit diagram of LED driving circuit in Fig. 2.As shown in figure 3, reference voltage Vref 2 such as (2) formula at this time
It is shown：
In above formula, it is assumed that the resistance value of first resistor R1 and tertiary voltage R3 are all R, then can calculate electricity from above formula
The size of the voltage VY of the second end of the switch SW2 of flow control circuit 220, that is to say, that voltage VY only can be by reference voltage
The influence of Vref1, Vref2, and reference voltage Vref 1, Vref2 are the parameters that can be accurately controlled, therefore flow through current control circuit
The electric current of 220 second resistance R2
By (1), (3) formula it is found that setting through this embodiment, the electric current I1 and electric current of current control circuit 210
The electric current I2 of control circuit 220 can all have stabling current value by stable reference voltage Vref 1, Vref2, therefore shine
The operation efficiency of diode can be promoted, thus can not provide light emitting diode stabling current in improvement known technology
Problem.
Referring to FIG. 4, Fig. 4 is the schematic diagram of the second embodiment of LED driving circuit of the present invention.Such as Fig. 4 institutes
Show, LED driving circuit 400 includes a first voltage source VCC1, (such as the four electric current controls of multiple current control circuits
Circuit processed 410,420,430,440) and a second resistance R2, wherein first voltage source VCC1 can pass through a bridge rectifier
480 carry out rectification, and but not limited to this.First voltage source VCC1 is coupled to multi-group light-emitting diode (such as four groups of hairs of concatenation
Optical diode 450_1,450_2,450_3 and 450_4, and according to actual circuit requirements, each group of light emitting diode
It may include the light emitting diode of one or multiple concatenations, in other words, the present invention does not limit to the hair of each group of light emitting diode
Optical diode number), to provide an input voltage vin.Note that is not influencing under the technology of the present invention exposure, and Fig. 4 is only
Four current control circuits 410~440 and four groups of light emitting diode 450_1~450_4 are illustrated, however, in fact, luminous two
Pole pipe driving circuit 200 may include N groups light emitting diode and N number of current control circuit, wherein the N group light emitting diode strings
It connects, first group of light emitting diode can connect first voltage source VCC1 to receive input voltage, and be connected to a current control
Circuit 410, the 2nd group of light emitting diode to (N-1) group light emitting diode can be separately connected (N-2) a current control circuit, and
Should in (N-2) a current control circuit the circuit framework of each with current control circuit 410 in identical such as the present embodiment,
The meeting of current control circuit 410,420,430 circuit framework having the same), in addition, N groups light emitting diode (that is, last
Group light emitting diode) then it is connected to current control circuit 440.
Current control circuit 410~440 is respectively coupled to multi-group light-emitting diode 450_1~450_4, each electric current control
Circuit processed all includes a first switch SW1, a second switch SW2, a comparator (operational amplifier) CR and a first resistor
R1.First switch SW1 and second switch SW2 may, for example, be transistor unit, but the present invention is not limited thereto.First
Switch SW1 and second switch SW2 includes a first end, a control terminal and a second end.The first end of second switch SW2
It is coupled to corresponding one group of light emitting diode, the control terminal of second switch SW2 is coupled to a second voltage source VCC2, and
The second end of two switch SW2 is coupled to the first end of first switch SW1.The second voltage source VCC2 is controlling second switch SW2
Unlatching (conducting) and close (being not turned on).When LED driving circuit 400 is run, second switch SW2 can be because the
Bias that two voltage source VCC2 are provided and open, therefore, the first end of first switch SW1 can be coupled to corresponding one group
Light emitting diode.
Comparator CR includes a positive input terminal (+), a negative input end (-) and an output end, the positive input of comparator CR
End is coupled to a corresponding reference voltage, and the output end of comparator CR is coupled to the control terminal of first switch SW1.First electricity
Resistance R1 is coupled between the negative input end of comparator CR and the second end of first switch SW1.Second resistance R2 is coupled to electric current
The second end of each first switch SW1 of control circuit 410~440 and a common reference voltage (such as ground voltage) it
Between.In addition, an at least current control circuit in current control circuit 410~440 (such as current control circuit 410,420,
430) additionally comprise a 3rd resistor R3, be coupled at least current control circuit (such as current control circuit 410,420,
430) negative input end of comparator CR and the first switch of another current control circuit (such as current control circuit 440)
Between the first end of SW1.It note that in LED driving circuit 400, in multiple current control circuits 410~440
It is coupled to the current control circuit 440 of last group of light emitting diode 450_4 and does not have 3rd resistor R3.In the present embodiment
In, first resistor R1 and 3rd resistor R3 are a kilohm grade, and second resistance R2 is ohm level, but the present invention not with
This is limited.
In addition, according to the demand in design, 1~Vref4 of reference voltage Vref may be configured as it is identical or different, also that is,
The positive input terminal of the comparator CR of multiple current control circuits 410~440 can be respectively coupled to different reference voltage or same
Reference voltage.The mode of operation of LED driving circuit 400 is as follows.
First, when the voltage source VCC input voltage vins provided are more than first group of light emitting diode 450_1 (this implementation
Example in a light emitting diode be used as example illustrate) cross-pressure VF1 but not greater than first and second group of light emitting diode
When the cross-pressure VF1+VF2 that 450_1,450_2 (being used as example in the present embodiment with a light emitting diode to illustrate) are added, electricity
Stream only can firstly flow through first group of light emitting diode 450_1.At this point, the second end of the first switch SW1 of current control circuit 410
Voltage can be equal to reference voltage Vref 1, therefore flow through the electric current I2 of second resistance R2 as shown in (4) formula：
Then, when input voltage vin becomes larger, and more than first and second group light emitting diode 450_1,450_2 are added
When cross-pressure VF1+VF2, electric current flows through second group of light emitting diode 450_2 at this time so that the of current control circuit 420
The voltage of the first end of one switch SW1 rises, therefore the voltage of the negative input end of the comparator CR of current control circuit 410
It can rise therewith, and then the voltage of the output end of the comparator CR of current control circuit 410 is caused to decline.When current control electricity
When the voltage of the output end of the comparator CR on road 410 deteriorates to less than a critical value, the first switch of current control circuit 410
SW1 (being realized with transistor) will be closed.At this point, the voltage of the second end of the first switch SW1 of current control circuit 420
Reference voltage Vref 2 can be equal to, therefore flow through the electric current I2 of second resistance R2 as shown in (5) formula：
The operation principles of other current control circuits and so on, so it will not be repeated.
From the above it can be seen that with the rising of input voltage vin and one by one switched-on light emitting diodes 450_1~450_4, flows through
The electric current I2 sizes of second resistance R2 can change as the voltage of 1~Vref4 of reference voltage Vref is set.Flow through the second electricity
The variation for hindering the electric current I2 sizes of R2 can refer to Fig. 5 and Fig. 6, and Fig. 5 is multiple comparators of multiple current control circuits in Fig. 4
Positive input terminal be respectively coupled to different reference voltages LED driving circuit current-vs-time figure, and Fig. 6 is
The positive input terminal of multiple comparators of multiple current control circuits inputs the light emitting diode driving of same reference voltage in Fig. 4
The current-vs-time figure of circuit.In Figure 5,1~Vref4 of reference voltage Vref be sequentially from large to small Vref4, Vref3,
Vref2, Vref1, therefore the waveform of the electric current I2 of LED driving circuit 400 can generally level off to string wave, so that hair
Optical diode driving circuit 400 can have preferred power factor (power factor) and total harmonic distortion (total
harmonic distortion).When input voltage vin is string wave voltage and 1~Vref4 of reference voltage Vref is also same phase
When string wave voltage, LED driving circuit 400 just has best power factor (power factor) and total harmonic wave
It is distorted (total harmonic distortion).In addition, to make the electric current I2 of LED driving circuit 400 keep
The voltage value of reference voltage Vref 4, Vref3, Vref2, Vref1 can be then set as identical by constant (constant), electric at this time
Flow I2 waveform as shown in fig. 6, and electric current I2 size as shown in (6) formula：
From the foregoing, it will be observed that in the present embodiment, the size of electric current I2 only can by reference voltage Vref 1, Vref2, Vref3,
The influence of Vref4, therefore the electric current for flowing through light emitting diode can have stabling current value by stable reference voltage, therefore send out
The operation efficiency of optical diode can be promoted, thus can not provide light emitting diode stabling current in improvement known technology
Problem.
Referring to FIG. 7, Fig. 7 is the schematic diagram of the 3rd embodiment of LED driving circuit of the present invention.Such as Fig. 7 institutes
Show, LED driving circuit 700 is similar to LED driving circuit 200, but LED driving circuit 700
Additionally comprise a holding circuit 710 and a triacs (TRIAC) 730.Holding circuit 710 includes above-mentioned
First switch SW1 and comparator CR, and it is couple to ground terminal via second resistance R2 above-mentioned.However, the present invention is not limited thereto,
First switch SW1 and comparator CR and its second resistance R2 coupled in holding circuit 710 can be according to designs
Demand is replaced into other switches, comparator and resistance.
Dimming unit using TRIAC as lighting device is common design, however in general lighting device, base
In the characteristic of TRIAC, the electric current that TRIAC is input to light emitting diode must be maintained at not less than a critical electric current value to ensure
The conducting of TRIAC can cause TRIAC moments to be closed, in turn result in once the input current of TRIAC is less than the critical electric current value
The phenomenon that light Suddenly it apperared and disappered (flickers).
It is found that when voltage VX rises, voltage VY can decline and reach pass (2) formula from present invention
The purpose of the first switch SW1 of current control circuit 220 is closed, similarly, the present embodiment is closed by means of the rising of voltage VY to reach
The purpose for closing the first switch SW1 of holding circuit 710 to reduce current loss, or makes first switch when voltage VY declines
SW1 is connected, and so that the dimming process of LED driving circuit 700 is able to very smooth out (smooth), also
Steadily shine.For example, the electric current IIN for flowing out TRIAC730 can be diverted to light emitting diode 230_2 and holding circuit
The positive input terminal of 710 comparator CR, wherein IIN=ILED+IH, VH are the maintenance voltages of the positive input terminal of comparator CR.When
Electric current ILED becomes larger, and when its size alreadys exceed critical electric current value, and voltage VY can be caused to rise, and makes under voltage VZ
Drop, and then holding circuit 710 (that is, electric current IH=0) is closed, achieve the effect that power saving；Conversely, when electric current ILED gradually becomes
It is small, and when its size is already below critical electric current value, holding circuit 710 will be opened, by means of making TRIAC730 continue to flow out
Electric current maintains its running, therefore can avoid the phenomenon that there is Suddenly it apperared and disappered light in known technology.Although in addition, in the example above,
Holding circuit 710 is simultaneously not provided with second switch SW2, but the present invention also can add second switch according to actual design demand
SW2.In addition, similar to the design of current control circuit 210,220, in holding circuit 710, the negative input end of comparator CR
It is coupled between a transmission gate TG1 and resistance R1, and is coupled with a resistance between transmission gate TG1 and current control circuit 220
R3。
Referring to FIG. 8, Fig. 8 is the schematic diagram of the fourth embodiment of LED driving circuit of the present invention.Such as Fig. 8 institutes
Show, LED driving circuit 800 is similar to LED driving circuit 400, but LED driving circuit 800
A holding circuit 810, resistance RH and R4 and a triacs (TRIAC) 830 are additionally comprised, wherein being similar to
The framework of the bridge rectifier 480 of LED driving circuit 400 has been integrated in TRIAC830.Similarly, work as TRIAC830
It exports to the electric current ILED of light emitting diode 450_1 and has reached greatly, TRIAC830 can stop output current IH；Conversely, working as
TRIAC830 export electric current ILED to light emitting diode 450_1 it is too small when, TRIAC 830 can output current IH prevent
TRIAC830 has the situation of flicker, the detailed operation principle of holding circuit 810 to be similar to the holding circuit 710 of previous embodiment,
Therefore it is repeated no more in this.In addition, holding circuit 810 can also add second switch SW2 according to actual design demand.In addition, tieing up
It holds in circuit 810, the negative input end of comparator CR is coupled between resistance R4 and resistance R5, and resistance R5 is coupled to maintenance
Between circuit 810 and current control circuit 410.
In conclusion through LED driving circuit provided by the present invention, it is steady light emitting diode can be provided according to this
Fixed electric current, and do not influenced by the variation on light emitting diode processing procedure, and then promote the operation efficiency of light emitting diode.This
Outside, the embodiment of Fig. 7-8 of the present invention more provides the light adjusting framework of collocation LED driving circuit, further to be promoted
Its luminous stability, and then it is luminous to make LED driving circuit that can stablize in dimming process, without having public affairs
Know the phenomenon that light is Suddenly it apperared and disappered in technology.
The foregoing is merely the preferred embodiment of the present invention, all equivalent changes done according to scope of the present invention patent
With modification, it should all belong to the covering scope of the present invention.
【Symbol description】
100,200,400,700,800 LED driving circuit
11,12,230_1,230_2,450_1, light emitting diode
450_2、450_3、450_4
20,30,210,220,410,420, current control circuit
430、440
22,32, CR comparators
T1, T2 transistor
Vref, Vref1, Vref2, Vref3, Vref4 reference voltage
VX, VY voltage
VF1, VF2, VF3, VF4 cross-pressure
I, I1, I2 electric current
VCC1 first voltage sources
VCC2 the second voltage sources
Vin input voltages
SW1 first switches
SW2 second switches
R1 first resistors
R2 second resistances
R3 3rd resistors
RH, R4, R5 resistance
TG1 transmission gates
480 bridge rectifiers
710,810 holding circuit
730,830 triacs
Claims (12)
1. a kind of light emitting diode (LED) driving circuit, including：
One first voltage source is coupled to multigroup LED of concatenation, to provide an input voltage；And multiple current control circuits,
It is respectively coupled to multigroup LED, each current control circuit includes：
One first switch, including a first end, a control terminal and a second end, the first end of the first switch is coupled to phase
Corresponding one group of LED；
One first comparator a, including positive input terminal, a negative input end and an output end, the positive input of the first comparator
End is coupled to a corresponding reference voltage, and the output end of the first comparator is coupled to the control terminal of the first switch；
One first resistor, including a first end and a second end, the second end of the first resistor is coupled to this and first compares
The first end of the negative input end of device, the first resistor is coupled between the second end of the first switch；And
One second resistance is coupled between the second end and a common reference voltage of the first switch；
An at least 3rd resistor, first end be coupled to the current control circuit in multiple current control circuit this first
The second end of switch；And
An at least transmission gate is coupled at least second end of a 3rd resistor and another electricity in multiple current control circuit
Between the negative input end of the first comparator of flow control circuit, wherein when an at least transmission gate is switched on, this is another
The second end of the first resistor of current control circuit is coupled directly to the second end of an at least 3rd resistor, when this extremely
When a few transmission gate is closed, the second end of the first resistor of another current control circuit and an at least 3rd resistor
The second end between be open circuit.
2. LED driving circuit as described in claim 1, wherein each current control circuit additionally comprises：
One second switch, including a first end, a control terminal and a second end, the first end of the second switch is coupled to phase
The control terminal of corresponding this group of LED, the second switch are coupled to a second voltage source, the second end coupling of the second switch
In the first end of the first switch.
3. LED driving circuit as described in claim 1, the wherein first voltage source through a bridge rectifier into
Row rectification.
4. LED driving circuit as described in claim 1, the wherein first resistor are kilohm (k ohm) grades, with
And the second resistance is ohm (ohm) grade.
5. LED driving circuit as described in claim 1, wherein being coupled to the string in multiple current control circuit
The current control circuit of last group of LED of the multigroup LED connect does not have the 3rd resistor and the transmission gate.
6. LED driving circuit as described in claim 1 additionally comprises a holding circuit, it is coupled to multiple electric current control
Between a current control circuit and the first voltage source in circuit processed, it is controllable which is separately coupled to a three terminal bidirectional
Silicon cell, the holding circuit include：
One third switchs, including a first end, a control terminal and a second end, the first end of third switch is coupled to phase
Corresponding one group of LED；
One second comparator a, including positive input terminal, a negative input end and an output end, the positive input of second comparator
End is coupled to the first end of third switch, and the output end of second comparator is coupled to the control of third switch
End；And
One the 4th resistance is coupled between second end and the collective reference voltage of third switch.
7. a kind of light emitting diode (LED) driving circuit, including：
One first voltage source is coupled to multigroup LED of concatenation, to provide an input voltage；
Multiple current control circuits, are respectively coupled to multigroup LED, and each current control circuit includes：
One first switch, including a first end, a control terminal and a second end, the first end of the first switch is coupled to phase
Corresponding one group of LED；
One first comparator a, including positive input terminal, a negative input end and an output end, the positive input of the first comparator
End is coupled to a corresponding reference voltage, and the output end of the first comparator is coupled to the control terminal of the first switch；With
And
One first resistor is coupled between the negative input end of the first comparator and the second end of the first switch；With
And
One second resistance is coupled to the second end and a common reference voltage of the first switch of each current control circuit
Between；
An at least current control circuit additionally comprises in wherein multiple current control circuit：
One 3rd resistor is coupled to the negative input end and another electricity of at least first comparator of a current control circuit
Between the first end of the first switch of flow control circuit.
8. LED driving circuit as claimed in claim 7, wherein each current control circuit additionally comprises：
One second switch, including a first end, a control terminal and a second end, the first end of the second switch is coupled to phase
The control terminal of corresponding this group of LED, the second switch are coupled to a second voltage source, the second end coupling of the second switch
In the first end of the first switch.
9. LED driving circuit as claimed in claim 7, the wherein first voltage source by a bridge rectifier into
Row rectification.
10. LED driving circuit as claimed in claim 7, wherein multiple first ratios of multiple current control circuit
Different reference voltages is respectively coupled to compared with the positive input terminal of device.
11. LED driving circuit as claimed in claim 7, wherein multiple first ratios of multiple current control circuit
It is coupled to same reference voltage compared with the positive input terminal of device.
12. LED driving circuit as claimed in claim 7 additionally comprises a holding circuit, it is coupled to multiple electric current
Between a current control circuit and the first voltage source in control circuit, which is separately coupled to a three terminal bidirectional can
Silicon cell is controlled, which includes：
One third switchs, including a first end, a control terminal and a second end, the first end of third switch is coupled to phase
Corresponding one group of LED；
One second comparator a, including positive input terminal, a negative input end and an output end, the positive input of second comparator
End is coupled to the first end of third switch, and the output end of second comparator is coupled to the control of third switch
End；And
One the 4th resistance is coupled between second end and the collective reference voltage of third switch.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410386129.0A CN105338683B (en) | 2014-08-07 | 2014-08-07 | LED driving circuit |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410386129.0A CN105338683B (en) | 2014-08-07 | 2014-08-07 | LED driving circuit |
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| CN105338683A CN105338683A (en) | 2016-02-17 |
| CN105338683B true CN105338683B (en) | 2018-07-17 |
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| CN106954295A (en) * | 2016-09-23 | 2017-07-14 | 上海占空比电子科技有限公司 | The actinic LED drive circuit of high-efficiency sectional thyristor regulating |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2009175382A (en) * | 2008-01-24 | 2009-08-06 | Hitachi Displays Ltd | Liquid crystal display |
| CN102685978A (en) * | 2011-03-16 | 2012-09-19 | 松下电器产业株式会社 | Illumination apparatus |
| CN103874260A (en) * | 2012-12-07 | 2014-06-18 | 普诚科技股份有限公司 | Lighting system and control method thereof |
| CN203748078U (en) * | 2014-03-10 | 2014-07-30 | 陕西亚成微电子股份有限公司 | High voltage linear power voltage compensation circuit |
-
2014
- 2014-08-07 CN CN201410386129.0A patent/CN105338683B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2009175382A (en) * | 2008-01-24 | 2009-08-06 | Hitachi Displays Ltd | Liquid crystal display |
| CN102685978A (en) * | 2011-03-16 | 2012-09-19 | 松下电器产业株式会社 | Illumination apparatus |
| CN103874260A (en) * | 2012-12-07 | 2014-06-18 | 普诚科技股份有限公司 | Lighting system and control method thereof |
| CN203748078U (en) * | 2014-03-10 | 2014-07-30 | 陕西亚成微电子股份有限公司 | High voltage linear power voltage compensation circuit |
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