CN105208730B - The LED drive circuit of currents match - Google Patents
The LED drive circuit of currents match Download PDFInfo
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- CN105208730B CN105208730B CN201510629832.4A CN201510629832A CN105208730B CN 105208730 B CN105208730 B CN 105208730B CN 201510629832 A CN201510629832 A CN 201510629832A CN 105208730 B CN105208730 B CN 105208730B
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Abstract
The present invention provides a kind of LED drive circuit of currents match, it includes：Reference current source；First resistor, its first connecting pin are connected with the output terminal of the reference current source, its second connection end is connected with ground terminal；Multiple LED drive branch, each LED drivings branch includes programmable operational amplifier, output transistor, driving resistance and mistuning calibration function circuit, first connecting pin of the output transistor can be connected as the output terminal of LED driving branches with powered LED, the first input end of the mistuning calibration function circuit and the first connecting pin of first resistor, second input terminal of the mistuning calibration function circuit is connected with the second input terminal of the programmable operational amplifier, and wherein first resistor and the build-out resistor is mutually matched reduces mutual relative error with most.Utilize the matched less feature of resistance relative error, there is provided more consistent LED drive current.
Description
【Technical field】
It is more particularly to a kind of the present invention relates to LED (light-emitting diode) drive circuit chip design field
The LED drive circuit of currents match.
【Background technology】
Multipath LED drive circuit is widely used in big screen LED display, such as the tablet computer of giant-screen, pen
Remember this computer, TV or giant-screen billboard.In these display devices, all backlight is provided by LED.Due to LED array very
It is big, it is necessary to LED multi-path drives, for the phase that ensures the uniformity of large screen display, it is necessary to which the driving current per paths of LEDs is all tried one's best
Deng.
Fig. 1 describes a kind of multipath LED drive circuit of the prior art, which describes the situation of two string LED outputs.Figure
In 1, the drain electrode of transistor MN3 is adjusted to 0.3V, the grid voltage phase of transistor MN41, MN42 and MN3 by operational amplifier OP1
Deng (ensured by operational amplifier OP2, OP2 by voltage GT adjustment equal to transistor MN3 grid voltage GN3.Operation amplifier at the same time
Device OP31 is adjusted so that the drain voltage DN41 of transistor MN41 is equal to voltage VD, and operational amplifier OP32 is adjusted so that transistor
The drain voltage DN42 of MN42 is also equal to voltage VD.Therefore the grid voltage of transistor MN41, MN42 are equal to transistor MN3's
Grid voltage, the drain voltage of transistor MN41, MN42 are also equal to the drain voltage of transistor MN3, transistor MN41,
The source electrode of MN42, MN3 are all grounded, and voltage is also equal.The drain current of so MN41, MN42 are proportional to the drain current of MN3, its
Ratio is the ratio between the breadth length ratio of MN41, MN42 with respect to MN3.It is all identical to be typically designed width and the length of MN41 and MN42, so
The electric current of MN41 and MN42 should be equal.But actual conditions, due to process deviation, between chip, MN41 drain currents and MN42
Drain current uniformity is not so preferable, and possible deviation is between -5% to+5%.Reduce the deviation, be conducive to improve large-size screen monitors
Display effect.Operational amplifier OP31 and OP32 first exists certain there are input deviation that is, between its positive-negative input end voltage
Small value deviation.Fig. 1 designs help to reduce the deviation to current mismatch by allowing MN3, MN41 and MN42 to be all operated in saturation region
Influence, even so, the input deviation of operational amplifier OP31 and OP31 can still result in MN41 and MN42 to a certain extent
Drain current mismatch.In addition, the mismatch between MN41 and MN42 also there are device in itself, for example, its threshold voltage there may be
Difference, its gate oxide thickness have differences there may be difference between the developed width and length of raceway groove.In addition operational amplifier
There is input mismatch in OP2, cause to have differences between the grid voltage of MN41, MN42 and the grid voltage of MN3, can so cause
There are chip chamber deviation for the drain current of transistor MN41, MN42 and the drain current ratio of transistor MN3.
It would therefore be highly desirable to propose a kind of LED drive circuit of improved currents match.
【The content of the invention】
It is an object of the present invention to providing a kind of LED drive circuit of improved currents match, it can drive more
Paths of LEDs, and keep the driving current of each paths of LEDs that there is higher uniformity.
To solve the above-mentioned problems, the present invention provides a kind of LED drive circuit, it includes：Reference current source；First electricity
Resistance, its first connecting pin are connected with the output terminal of the reference current source, its second connection end is connected with ground terminal；Multiple LED
Branch is driven, each LED drivings branch includes programmable operational amplifier, output transistor, driving resistance and mistuning calibration function electricity
Road, wherein the first connecting pin of the first input end of the programmable operational amplifier and first resistor, its second input terminal with
First connecting pin of driving resistance is connected, the second connection end phase for driving the first connecting pin of resistance also with output transistor
Even, it is described driving resistance second connection end be connected with ground terminal, the output terminal of the programmable operational amplifier with it is described defeated
The control terminal for going out transistor is connected, and the first connecting pin of the output transistor can as the output terminal of LED driving branches
It is connected with powered LED, the first input end of the mistuning calibration function circuit and the first connecting pin of first resistor, the imbalance
Second input terminal of calibration circuit is connected with the second input terminal of the programmable operational amplifier, and the mistuning calibration function circuit is defeated
The calibration signal that deviates gives the programmable operational amplifier, and the programmable operational amplifier is based on the deviation calibration signal
Calibrated, wherein first resistor and the build-out resistor is mutually matched reduces mutual relative error with most.
Further, the relative error of first resistor and the build-out resistor is less than or equal to +/- 0.1%.
Further, the output transistor is nmos pass transistor, and the source electrode of the nmos pass transistor is brilliant for the output
The second connection end of body pipe, the drain electrode of the nmos pass transistor are the first connecting pin of the output transistor.
Further, the output terminal of the cathode of the powered LED and the LED driving branch is connected, its anode with
Power voltage terminal is connected.
Further, the first input end of the mistuning calibration function circuit in one of LED drivings branch is also connected to separately
First connecting pin of the driving resistance in one LED driving branch.
Further, the mistuning calibration function circuit is higher than second in the voltage of the first input end of the mistuning calibration function circuit
The voltage of input terminal and the first predetermined threshold and when, adjust its deviation calibration signal, the mistuning calibration function circuit is in the mistake
The voltage of the first input end of the quasi- circuit of adjustment less than the second input terminal voltage and the second predetermined threshold difference when, it is inclined to adjust its
Poor calibration signal, it is predetermined less than the voltage of the second input terminal and first in the voltage of the first input end of the mistuning calibration function circuit
Threshold value and and higher than the second input terminal voltage and the second predetermined threshold difference when, keep its deviation calibration signal.
Further, the mistuning calibration function circuit includes first voltage comparison circuit, second voltage comparison circuit and logic
Output circuit, first voltage comparison circuit are higher than the second input terminal in the voltage of the first input end of the mistuning calibration function circuit
Voltage and the first predetermined threshold and when, it exports first signal, otherwise exports secondary signal；Second voltage comparison circuit is in institute
State the voltage of the first input end of mistuning calibration function circuit less than the second input terminal voltage and the second predetermined threshold difference when, its is defeated
Go out the first signal, otherwise export secondary signal；The logical output circuit first voltage comparison circuit export the first signal and
When second voltage comparison circuit exports secondary signal, increase its deviation calibration signal, second is exported in first voltage comparison circuit
When signal and second voltage comparison circuit the first signal of output, reduce its deviation calibration signal, it is defeated in first voltage comparison circuit
When going out secondary signal and second voltage comparison circuit output secondary signal, its deviation calibration signal is kept.
Further, the programmable operational amplifier includes：First difference transistor and the second difference transistor, wherein
First difference transistor or the second difference transistor include multiple differential crystal pipe units in parallel, Partial Differential transistor list
Each in member is connected with a programmable switch, and the control terminal of the programmable switch receives the deviation calibration signal,
Under the control of the deviation calibration signal, the programmable switch on or off.
Further, the programmable operational amplifier includes multiple output resistances of the series connection on output branch,
First connecting pin of each output resistance is connected by a programmable switch with the output terminal of the programmable operational amplifier,
The control terminal of the programmable switch receives the deviation calibration signal, under the control of the deviation calibration signal, it is described can
Program switch on or off.
Compared with prior art, the present invention is by setting the resistance that is mutually matched, using matched resistance relative error compared with
The characteristics of small, there is provided more consistent LED drive current.In addition, the input offset voltage of operational amplifier can be by imbalance school
Quasi- circuit calibrates to very little, so as to further improve the uniformity of each paths of LEDs driving current.
【Brief description of the drawings】
In order to illustrate the technical solution of the embodiments of the present invention more clearly, required use in being described below to embodiment
Attached drawing be briefly described, it should be apparent that, drawings in the following description are only some embodiments of the present invention, for this
For the those of ordinary skill of field, without having to pay creative labor, it can also be obtained according to these attached drawings other
Attached drawing.Wherein：
Fig. 1 illustrates the examples of circuits figure of LED drive circuit of the prior art；
Fig. 2 illustrates the examples of circuits figure of LED drive circuit in one embodiment in the present invention；
Fig. 3 illustrates the examples of circuits figure of mistuning calibration function circuit in one embodiment in Fig. 2；
Fig. 4 illustrates the examples of circuits figure of programmable operational amplifier in one embodiment in Fig. 2；
Fig. 5 illustrates the examples of circuits figure of programmable operational amplifier in another embodiment in Fig. 2；
Fig. 6 illustrates the examples of circuits figure of logical output circuit in one embodiment in Fig. 3；
Fig. 7 illustrates the examples of circuits figure of LED drive circuit in another embodiment in the present invention.
【Embodiment】
In order to make the foregoing objectives, features and advantages of the present invention clearer and more comprehensible, it is below in conjunction with the accompanying drawings and specific real
Applying mode, the present invention is described in further detail.
The present invention provides the multipath LED drive circuit of improved currents match, it can drive LED multi-path, and respectively
The uniformity of the driving current of paths of LEDs is higher.
Fig. 2 illustrates the examples of circuits figure of LED drive circuit 200 in one embodiment in the present invention.Such as Fig. 2 institutes
Show, the LED drive circuit 200 includes reference current source I21, first resistor R1 and multiple LED driving branches.Show in Fig. 2
Two LED driving branches are gone out, have been denoted as 210,220 respectively, in other embodiments, or three tunnels, four tunnels or more
Road.Each LED drivings branch drives a paths of LEDs, and the cathode of powered LED is connected with the output terminal of LED driving branches, is driven
The anode of dynamic LED is connected with power voltage terminal VCC.Specifically, the output terminal phase of the cathode of LED1 and LED driving branches 210
Even, the cathode of LED2 is connected with the output terminal of LED driving branches 220, the anode of LED1 and the anode of LED2 and power voltage terminal
VCC is connected.The first connecting pin of first resistor R1 is connected with the output terminal of the reference current source I21, its second connection end with
Ground terminal is connected.
As shown in Figure 2, it is each to drive branch to include programmable operational amplifier, output transistor, driving resistance and mistake
The quasi- circuit of adjustment.The first input end of wherein described programmable operational amplifier and the first connecting pin of first resistor R1, it the
Two input terminals with driving the first connecting pin of resistance to be connected, the first connecting pin of the driving resistance also with output transistor the
Two connecting pins are connected, and the second connection end of the driving resistance is connected with ground terminal, the output of the programmable operational amplifier
End is connected with the control terminal of the output transistor, the first input end VP of the mistuning calibration function circuit and the programmable computing
The first input end of amplifier is connected, the second input terminal VN and the programmable operational amplifier of the mistuning calibration function circuit
Second input terminal is connected, and the mistuning calibration function circuit output deviation calibration signal D0-Dn-1 gives the programmable operational amplifier,
The programmable operational amplifier is calibrated based on the deviation calibration signal.
First resistor R1 and the build-out resistor are mutually matched to reduce mutual relative error as far as possible.
Specifically, the programmable operational amplifier in the driving branch 210 is OP21, in the driving branch 210
Output transistor is nmos pass transistor MN21, and the driving resistance in the driving branch 210 is R2, in the driving branch 210
Mistuning calibration function circuit be the first mistuning calibration function circuit；Programmable operational amplifier in the driving branch 220 is OP22, institute
It is nmos pass transistor MN22 to state the output transistor in driving branch 220, and the driving resistance in the driving branch 220 is R3,
Mistuning calibration function circuit in the driving branch 220 is the second mistuning calibration function circuit.Programmable operational amplifier is OP21, OP22
First input end be normal phase input end, the second input terminal is negative-phase input.The source electrode of nmos pass transistor MN21 and MN22 is
The second connection end of output transistor, the drain electrode of nmos pass transistor MN21 and MN22 are the first connecting pin of output transistor,
The grid of nmos pass transistor MN21 and MN22 are the control terminal of output transistor.
In the present invention, by selecting type identical, by meticulous matched design, first resistor R1 and build-out resistor R2
Relative error between R3 can be designed into 0.1% precision.In the present invention, resistance R1, R2, R3 will pass through matching meticulously and set
Meter, its relative scale are very accurate.Such as the known various technologies of industry can be used, as central symmetry designs and keep every
The current direction of one section of resistance is all identical, and the width of each section of resistance all designs identical with length.
In the present invention, reference current source I21 provides reference current I21, and reference current I21 flows through resistance R1 and produces with reference to electricity
Press VD.Operational amplifier OP21 and OP22 are adjusted so that the voltage of node SN51 and SN52 are equal to voltage VD.Fortune in the present invention
It is different from conventional operational amplifiers to calculate amplifier OP21 and OP22, is its input deviation programmable operational amplifier.By n partially
Poor calibration signal D0~Dn-1, thus it is possible to vary the input deviation voltage (or input offset voltage) of operational amplifier.Computing is put
The input deviation of big device OP21 and OP22 are all calibrated within small value, such as 1mV by corresponding mistuning calibration function circuit.By school
It can ensure node VD voltages and the voltage deviation very little of node SN51, SN52 after standard, can be approximated to be and think equal.It is not calibrated
Normal operation amplifier there may be the up to input deviation of 30mV.Design deviation calibration signal digit is more, it is possible to achieve
The calibration accuracy of higher.According to kirchhoff KCL laws, the electric current of LED1 is equal to resistance R2 electric currents, and the electric current of LED2 is equal to electricity
Hinder the electric current of R3.According to above-mentioned principle, the electric current of R2 is equal to I21.R1/R2, and the electric current of R3 is equal to I21.R1/R3.When R2 is equal to
During R3, the electric current of LED1 and LED2 are equal.Since R1 and R2, and R1 and R3 employ the design being mutually matched, their phase
It is very small to error, therefore the error between the electric current on R2 and R3 is also very small.It is it is to be understood that electric in integrated circuits
The matching of resistance is far above the matching of transistor.
As shown in Figure 2, voltage VP high of the mistuning calibration function circuit in the first input end of the mistuning calibration function circuit
In the voltage VN of the second input terminal and the first predetermined threshold (can be zero) and when, increase its deviation calibration signal D0-Dn-1,
The mistuning calibration function circuit is less than the voltage VN of the second input terminal in the voltage VP of the first input end of the mistuning calibration function circuit
During with the difference of the second predetermined threshold, reduce its deviation calibration signal D0-Dn-1.In the first input end of the mistuning calibration function circuit
Voltage less than the second input terminal voltage and the first predetermined threshold and and voltage higher than the second input terminal and second predetermined
During the difference of threshold value, its deviation calibration signal D0-Dn-1 is kept.
As shown in figure 3, the mistuning calibration function circuit includes first voltage comparison circuit 310, second voltage comparison circuit 320
With logical output circuit 330.Voltage of the first voltage comparison circuit 310 in the first input end VP of the mistuning calibration function circuit is high
In the second input terminal voltage and the first predetermined threshold and when, its export first signal, otherwise export secondary signal；At this time
One predetermined threshold is 0.Second voltage comparison circuit 320 is less than second in the voltage of the first input end of the mistuning calibration function circuit
During the difference of the voltage of input terminal and the second predetermined threshold, it exports the first signal, otherwise exports secondary signal, and second is predetermined at this time
Threshold value is voltage Ve.The logical output circuit 330 exports the first signal and second voltage ratio in first voltage comparison circuit 310
When exporting secondary signal compared with circuit 320, increase its deviation calibration signal, secondary signal is exported in first voltage comparison circuit 310
And during the first signal of output of second voltage comparison circuit 320, reduce its deviation calibration signal, in first voltage comparison circuit 310
When exporting secondary signal and the output secondary signal of second voltage comparison circuit 320, its deviation calibration signal is kept.
Specifically, first voltage comparison circuit 310 includes switch S12, S11, S13, phase inverter INV11, phase inverter
INV13, phase inverter INV14, operational amplifier OP5, d type flip flop ffdf1 and capacitance C11.Wherein first input end VP is by opening
Close S12 with the normal phase input end of operational amplifier OP5 to be connected, the second input terminal VN is by switch S11 and operational amplifier OP5's
Normal phase input end is connected.The negative-phase input of operational amplifier OP5 is connected by capacitance C11 with ground terminal, and negative-phase input is also
It is connected by switching S13 with its output terminal.Clock signal CK1 is connected with switching the control terminal of S11, and passes through phase inverter INV11
It is connected with the control terminal for switching S12.Phase inverter INV13, phase inverter INV14 are sequentially connected in series in the input terminal of operational amplifier OP5
Between the input terminal d of d type flip flop ffdf1, the clock end of d type flip flop ffdf1 is connected with clock signal CK4.D type flip flop
The output terminal q output signals VH of ffdf1.It is the first signal in the high level of signal VH, low level is secondary signal.
Specifically, second voltage comparison circuit 320 includes switch S22, S21, S23, phase inverter INV21, phase inverter
INV23, phase inverter INV24, operational amplifier OP4, d type flip flop ffdf2 and capacitance C21.Wherein first input end VP is by opening
Pass S22, voltage source Ve are connected with the normal phase input end of operational amplifier OP4, and the second input terminal VN is put by switch S21 with computing
The normal phase input end of big device OP4 is connected.The negative-phase input of operational amplifier OP4 is connected by capacitance C21 with ground terminal, negative
Input terminal is also connected by switching S23 with its output terminal.Clock signal CK1 is connected with switching the control terminal of S21, and by anti-phase
Device INV21 is connected with switching the control terminal of S22.Phase inverter INV23, phase inverter INV24 are sequentially connected in series in operational amplifier OP4's
Between input terminal and the input terminal d of d type flip flop ffdf2, the clock end of d type flip flop ffdf2 is connected with clock signal CK4.D is triggered
The output terminal q output signals VL of device ffdf2.It is the first signal in the high level of signal VL, low level is secondary signal.
Specifically, as shown in Figure 3, when VP voltages are more than VN voltages, VH is changed into high level, and the logical output circuit is defeated
The deviation calibration signal D0-Dn-1 gone out adds 1；When VP voltages are less than VN-Ve, VL is changed into high level, and the logical output circuit is defeated
The deviation calibration signal D0-Dn-1 gone out subtracts 1.When VP voltages are between VN and VN-Ve, VH and VL are low level, this is patrolled
The deviation calibration signal D0-Dn-1 for collecting output circuit output remains unchanged.
Fig. 6 illustrates the examples of circuits figure of logical output circuit 330 in one embodiment in Fig. 3.As shown in Figure 6
, in order to simplify description, simply it is introduced herein by taking 2 deviation calibration signals as an example.In practice, can design as needed
The implementation of more long number.It can be realized with Digital Design mode, such as by writing verilog or VHDL codes, by soft
Circuit needed for the generation of part automatic Synthesis.The logical output circuit 330 include OR gate OR1, OR2, OR3, with door AND1, AND2,
AND3, AND4, nor gate NOR1, phase inverter INV2, phase inverter INV3, phase inverter INV1, d type flip flop ffdf3, ffdf4.Specifically
Connection relation it is as shown in Figure 6.
Fig. 4 illustrates the examples of circuits figure of programmable operational amplifier in one embodiment in Fig. 2.Such as Fig. 4 institutes
Show, the programmable operational amplifier includes the first difference transistor MP7 and the second difference transistor 410, wherein second is poor
Transistor 410 is divided to include multiple differential crystal pipe unit MP81, MP82, MP8n, MP8 in parallel, Partial Differential transistor list
Each in first MP81, MP82, MP8n is connected with programmable switch MPS1, MPS2, a MPSn, the programmable switch
The control terminal of MPS1, MPS2, MPSn receive the deviation calibration signal D0-Dn-1, under the control of the deviation calibration signal,
Programmable switch MP81, MP82, MP8n on or off.As shown in Figure 4, the programmable operational amplifier further includes
Current source I1, I2, nmos pass transistor MN1, MN2, MN3.By programmable switch MP81, MP82, MP8n described on or off,
Difference transistor unit MP81, MP82, MP8n can be caused to introduce the second difference transistor 410, so as to trim the programmable fortune
Calculate the input deviation voltage of amplifier.
Fig. 5 illustrates the examples of circuits figure of programmable operational amplifier in another embodiment in Fig. 2.Such as Fig. 5
Shown, the programmable operational amplifier includes multiple output resistance R5n-R51 of the series connection on output branch, each
The first connecting pin of output resistance R5n-R51 passes through a programmable switch SW1-SWn and the programmable operational amplifier
Output terminal is connected, and the control terminal of the programmable switch SW1-SWn receives the deviation calibration signal D0-Dn-1, described inclined
Under the control of poor calibration signal D0-Dn-1, the programmable switch SW1-SWn on or off.By described on or off
Programmable switch SW1-SWn, can adjust the input deviation voltage of the programmable operational amplifier.It is as shown in Figure 5, it is described can
Calculation by program amplifier further includes current source I51, I52, nmos pass transistor MN1, MN2, MN3, difference transistor MP7 and MP8.
Fig. 7 illustrates the examples of circuits figure of LED drive circuit in another embodiment in the present invention.In Fig. 7
The difference of LED drive circuit and the LED drive circuit shown in Fig. 2 is：Second in the LED drivings branch 220 loses
The first input end VP of the quasi- circuit of adjustment is connected to the first connecting pin of the driving resistance R2 in the LED drivings branch 210, and
As shown in Figure 2, the first input end VP of the second mistuning calibration function circuit in the LED drivings branch 220 is connected to the first electricity
Hinder the first connecting pin of R1.In this way, it can equally realize the effect of high matching precision in the present invention.
The word that connection in the present invention, the expression such as connect, be connected are electrically connected all referring to direct or indirect electric connection,
It is described to refer to be electrically connected by an element, such as capacitance, inductance or transistor etc. indirectly.
It is pointed out that any change that one skilled in the art does the embodiment of the present invention
All without departing from the scope of claims of the present invention.Correspondingly, the scope of claim of the invention is also not merely limited to
In previous embodiment.
Claims (9)
1. a kind of LED drive circuit, it is characterised in that it includes：
Reference current source；
First resistor, its first connecting pin are connected with the output terminal of the reference current source, its second connection end and ground terminal phase
Even；
Multiple LED drive branches, each LED drivings branch include programmable operational amplifier, output transistor, driving resistance and
Mistuning calibration function circuit, wherein the first connecting pin of the first input end of the programmable operational amplifier and first resistor, it
Two input terminals with driving the first connecting pin of resistance to be connected, the first connecting pin of the driving resistance also with output transistor the
Two connecting pins are connected, and the second connection end of the driving resistance is connected with ground terminal, the output of the programmable operational amplifier
End is connected with the control terminal of the output transistor, and the first connecting pin of the output transistor is as LED driving branches
Output terminal can be connected with powered LED, the first input end of the mistuning calibration function circuit and the first connection of first resistor
End, the second input terminal of the mistuning calibration function circuit are connected with the second input terminal of the programmable operational amplifier, the mistake
The quasi- circuit output deviation calibration signal of adjustment gives the programmable operational amplifier, and the programmable operational amplifier is based on described
Deviation calibration signal is calibrated,
Wherein first resistor and the driving resistance is mutually matched to reduce mutual relative error as far as possible.
2. LED drive circuit according to claim 1, it is characterised in that first resistor and it is described driving resistance it is opposite
Error is less than or equal to +/- 0.1%.
3. LED drive circuit according to claim 1, it is characterised in that the output transistor is nmos pass transistor, institute
The source electrode for stating nmos pass transistor is the second connection end of the output transistor, and the drain electrode of the nmos pass transistor is the output
First connecting pin of transistor.
4. LED drive circuit according to claim 1, it is characterised in that the cathode of the powered LED with it is described
The output terminal of LED driving branches is connected, its anode is connected with power voltage terminal.
5. the LED drive circuit according to claim 1, it is characterised in that " imbalance in one of LED drivings branch
Calibrate the first input end of circuit and the first connecting pin of first resistor ", replace with " the mistake in one of LED drivings branch
The first input end of the quasi- circuit of adjustment is connected to the first connecting pin of the driving resistance in another LED driving branches ".
6. LED drive circuit according to claim 1, it is characterised in that the mistuning calibration function circuit is in the imbalance school
The voltage of the first input end of quasi- circuit higher than the second input terminal voltage and the first predetermined threshold and when, adjust its deviation school
Calibration signal, the mistuning calibration function circuit are less than the electricity of the second input terminal in the voltage of the first input end of the mistuning calibration function circuit
When pressure and the difference of the second predetermined threshold, its deviation calibration signal is adjusted, in the electricity of the first input end of the mistuning calibration function circuit
Force down in the second input terminal voltage and the first predetermined threshold and and higher than the second input terminal voltage and the second predetermined threshold
Difference when, keep its deviation calibration signal.
7. LED drive circuit according to claim 6, it is characterised in that the mistuning calibration function circuit includes first voltage
Comparison circuit, second voltage comparison circuit and logical output circuit,
First voltage comparison circuit is higher than the voltage of the second input terminal in the voltage of the first input end of the mistuning calibration function circuit
With the first predetermined threshold and when, its export first signal, otherwise export secondary signal；
Second voltage comparison circuit is less than the voltage of the second input terminal in the voltage of the first input end of the mistuning calibration function circuit
During with the difference of the second predetermined threshold, it exports first signal, otherwise exports secondary signal；
The logical output circuit exports the first signal and second voltage comparison circuit output second in first voltage comparison circuit
During signal, increase its deviation calibration signal, export secondary signal in first voltage comparison circuit and second voltage comparison circuit is defeated
When going out the first signal, reduce its deviation calibration signal, export secondary signal in first voltage comparison circuit and second voltage compares
During circuit output secondary signal, its deviation calibration signal is kept.
8. LED drive circuit according to claim 1, it is characterised in that the programmable operational amplifier includes：First
Difference transistor and the second difference transistor, wherein the first difference transistor or the second difference transistor include it is multiple in parallel
Differential crystal pipe unit, each in Partial Differential transistor unit are connected with a programmable switch, the programmable switch
The control terminal of pass receives the deviation calibration signal, under the control of the deviation calibration signal, the programmable switch conducting
Or cut-off.
9. LED drive circuit according to claim 1, it is characterised in that the programmable operational amplifier includes being located at
Multiple output resistances of the series connection on branch are exported, the first connecting pin of each output resistance passes through a programmable switch and institute
The output terminal for stating programmable operational amplifier is connected, and the control terminal of the programmable switch receives the deviation calibration signal,
Under the control of the deviation calibration signal, the programmable switch on or off.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201510629832.4A CN105208730B (en) | 2015-09-28 | 2015-09-28 | The LED drive circuit of currents match |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201510629832.4A CN105208730B (en) | 2015-09-28 | 2015-09-28 | The LED drive circuit of currents match |
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| Publication Number | Publication Date |
|---|---|
| CN105208730A CN105208730A (en) | 2015-12-30 |
| CN105208730B true CN105208730B (en) | 2018-04-13 |
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| CN201510629832.4A Active CN105208730B (en) | 2015-09-28 | 2015-09-28 | The LED drive circuit of currents match |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN106898310B (en) * | 2017-03-21 | 2019-03-01 | 京东方科技集团股份有限公司 | A kind of circuit, backlight, display device for expanding LED quantity |
| CN113252949B (en) * | 2021-05-13 | 2021-11-05 | 北京芯格诺微电子有限公司 | High-precision current sampling circuit with on-chip real-time calibration |
| CN114360451A (en) * | 2022-01-27 | 2022-04-15 | 成都利普芯微电子有限公司 | Constant-current driving circuit, driving chip and electronic device for LED display screen |
| CN114489212A (en) * | 2022-01-27 | 2022-05-13 | 成都利普芯微电子有限公司 | Constant current source calibration circuit, constant current source drive circuit, drive chip and electronic equipment |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101674693A (en) * | 2009-10-01 | 2010-03-17 | 英飞特电子（杭州）有限公司 | Multichannel constant-current control circuit applicable to LED driver |
| CN201742604U (en) * | 2010-06-01 | 2011-02-09 | 艾迪光电（杭州）有限公司 | Multi-path LED current-equalizing control circuit |
| CN102256421A (en) * | 2011-07-28 | 2011-11-23 | 林万炯 | High-precision multipath LED (light-emitting diode) current-equalizing circuit |
| CN102458005A (en) * | 2010-10-22 | 2012-05-16 | 英飞特电子（杭州）有限公司 | LED multi-path output current equalizing circuit |
| CN102881251A (en) * | 2012-08-20 | 2013-01-16 | 深圳市易事达电子股份有限公司 | Current drive circuit |
-
2015
- 2015-09-28 CN CN201510629832.4A patent/CN105208730B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101674693A (en) * | 2009-10-01 | 2010-03-17 | 英飞特电子（杭州）有限公司 | Multichannel constant-current control circuit applicable to LED driver |
| CN201742604U (en) * | 2010-06-01 | 2011-02-09 | 艾迪光电（杭州）有限公司 | Multi-path LED current-equalizing control circuit |
| CN102458005A (en) * | 2010-10-22 | 2012-05-16 | 英飞特电子（杭州）有限公司 | LED multi-path output current equalizing circuit |
| CN102256421A (en) * | 2011-07-28 | 2011-11-23 | 林万炯 | High-precision multipath LED (light-emitting diode) current-equalizing circuit |
| CN102881251A (en) * | 2012-08-20 | 2013-01-16 | 深圳市易事达电子股份有限公司 | Current drive circuit |
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