CN103857135B - LED driver controller, LED driver and LED driving method - Google Patents
LED driver controller, LED driver and LED driving method Download PDFInfo
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Abstract
The invention discloses an LED driver controller, an LED driver and an LED driving method. The LED driver controller comprises a plurality of terminals (411 and 414) which can be connected with a plurality of LED strings respectively. For each LED string (42), the LED driver controller further comprises channel regulators (412 and 415) which can regulate currents passing through the LED strings (42) according to the detection voltages of the corresponding LED strings, and a first transistor (413) which can turn on or off the LED strings (42) according to first duty ratio signals, wherein the first duty ratio signals are determined based on currents regulated by the channel regulators (412 and 415). The problem of temperature rising of the LED driver controller can be solved.
Description
Technical field
Embodiments of the present invention are related to led and drive field and in particular to a kind of led driver controller, led driver
And led driving method.
Background technology
Light emitting diode (light emitting diode, referred to as led) is widely adopted in multiple electronic application,
For example: architectural lighting, vehicle head taillight, liquid crystal display including personal computer and HDTV backlight with
And flash lamp etc..Compared with the conventional lighting sources of such as electric filament lamp and fluorescent lamp etc, led has that efficiency high, directivity be good, color
Coloured silk has good stability, reliability high, life-span length, the remarkable advantage such as small volume and environmental safety.
In order to a big led array is driven using direct current (direct current, abbreviation dc) voltage source, commonly used
The dc-dc switching power manager of such as boosting, blood pressure lowering or buck-boost manager etc, going here and there to multiple led provides top
Rail voltage.For example, in liquid crystal display (lcd) application using led backlight, multiple led strings are given using power supervisor
Output voltage is provided.It is explained with reference to Fig. 1.
Fig. 1 is the schematic diagram of the led driver according to correlation technique, as shown in figure 1, this led driver to include direct current defeated
Enter voltage 11, power supervisor 12 and multiple led string (in Fig. 1 only) taking a led string 13 and the 2nd led string 14 as a example.Wherein
Power supervisor 11, according to the control of the first digital to analog converter 151 in led driver controller 15, is connected with each led string
Connect to provide output voltage.
In Fig. 1, in the passage belonging to a led string 13, comprise passage actuator 152 (for example, linear differential pressure regulator
152) with the first transistor 153, wherein this passage actuator 152 is used for controlling the electric current in a led string 13, first crystal
Pipe 153 is turned on and off a led string 13 according to the first pulse-width signal (pwm in 1).Similarly, the 2nd led string 14 institutes
Second channel actuator 154 and transistor seconds 155 is comprised, wherein this second channel actuator 154 is used for controlling in the passage belonging to
Make the electric current in the 2nd led string 14, transistor seconds 155 is turned on and off according to the second pulse-width signal (pwm in 2)
2nd led string 14.
Led is current-driven apparatus, and this means that the luminous flux being produced by led string is mainly average with go here and there by led
Electric current is related.Therefore, in order to ensure the brightness of each led string is identical, then the average current gone here and there by each led must phase
With.Therefore, the electric current in the electric current and the 2nd led string 14 generally in setting the led string 13 is identical, and the first pulsewidth modulation
Signal (pwm in 1) and the second pulse-width signal (pwm in 2), so that it is guaranteed that the average current and the of a led string 13
The average current of two led strings 14 is identical, and then guarantees that a led string 13 is identical with the brightness of the 2nd led string 14.
But, the voltage drop due to the difference manufacturing between led, therefore for identical average current, between led string
Also there is sizable difference.Particularly in much individual led string extensions, can drive in the led being made up of multiple passage actuators
Heat skewness or heat accumulation are caused on dynamic device controller, thus causing this led driver controller temperature to raise, very
To burning.
Content of the invention
This specification aims to provide a kind of led driver controller, led driver and led driving method, can solve the problem that phase
In the technology of pass, on the led driver controller being made up of multiple passage actuators, heat skewness or heat gather and make
This led driver controller temperature becoming raises the problem even burnt.
According to an aspect of the invention, it is provided a kind of led driver controller, comprising: multiple terminals, can connect respectively
Connect multiple led strings；For each led string, led driver controller also includes: passage actuator, operable corresponding with basis
Detection voltage in led string, adjusts the electric current gone here and there by led；And the first transistor, operable with according to first dutycycle believe
Number it is turned on and off led string (42), the wherein first duty cycle signals are the electric current being adjusted based on passage actuator and determine.
In one embodiment, passage actuator includes: transistor seconds, the operable electric current gone here and there by led with regulation；
And feedback circuit, operable so that detection voltage to be compared with first voltage threshold value set in advance, and in response to this ratio
Relatively result, controls transistor seconds.
In one embodiment, feedback circuit includes: the first operational amplifier, its input and transistor seconds in the same direction
Grid is connected, and reverse input end is connected with first voltage threshold value；First digital to analog converter, its input is put with the first computing
The outfan of big device is connected；And second operational amplifier, the outfan phase of its input and first digital to analog converter in the same direction
Connect, reverse input end is connected with the source electrode of transistor seconds, and outfan is connected with the grid of transistor seconds.
In one embodiment, feedback circuit also operable so that detection voltage to be entered with second voltage threshold value set in advance
Row compares, and in response to this comparative result, controls power supervisor, and wherein power supervisor is used for multiple led strings in parallel
Output voltage is provided.
In one embodiment, feedback circuit includes: the 3rd operational amplifier, its input and transistor seconds in the same direction
Grid is connected, and reverse input end is connected with second voltage threshold value；Second digital to analog converter, its input is put with the 3rd computing
The outfan of big device is connected, and outfan is connected with power supervisor.
In one embodiment, the first duty cycle signals and the product of electric current being adjusted be equal to baseline duty cycle signals with
The product of base current.
According to another aspect of the present invention, there is provided a kind of led driver, comprising: any of the above-described kind of led driver
Controller；And power supervisor, for providing output voltage to multiple led strings in parallel.
According to a further aspect of the invention, there is provided a kind of led driving method, comprising: for multiple led strings in parallel
In each led string, according to the detection voltage in led string, adjust the electric current gone here and there by led；And believed according to the first dutycycle
Number it is turned on and off led string, the wherein first duty cycle signals are to determine based on the electric current being adjusted.
In one embodiment, according to the detection voltage in led string, adjust and included by the electric current that led goes here and there: electricity will be detected
Pressure is compared with first voltage threshold value set in advance；In response to this comparative result, control transistor seconds to adjust and pass through led
The electric current of string.
In one embodiment, in response to this comparative result, control the electric current bag that transistor seconds regulation is gone here and there by led
Include: if this comparative result instructed voltage is more than first voltage threshold value, control the electricity that transistor seconds raising is gone here and there by led
Stream.
In one embodiment, if the electric current on led string reaches the upper current limit of this led string, and the inspection in this led string
Survey voltage still above first threshold voltage, then control power supervisor to reduce output voltage to multiple led strings in parallel.
In one embodiment, the detection voltage in being gone here and there according to led, before adjusting the electric current gone here and there by led, above-mentioned side
Method also includes: detection voltage is compared with second voltage threshold value set in advance；In response to this comparative result, control power supply
Manager provides output voltage to multiple led strings in parallel.
In one embodiment, in response to this comparative result, power supervisor is controlled to provide to multiple led strings in parallel defeated
Go out voltage to include: if this comparative result instructed voltage is less than second voltage threshold value, control power supervisor many to parallel connection
Individual led string improves output voltage.
In one embodiment, the first duty cycle signals and the product of electric current being adjusted be equal to baseline duty cycle signals with
The product of base current.
The present invention adjusts, using passage actuator, the electric current gone here and there by led, can adjust the voltage drop on passage actuator,
Thus adjusting the power loss on passage actuator, and then, when many led strings extend, it is possible to reduce led driver control
Heat skewness on device or heat accumulation, the temperature solving this led driver controller raises problem.Meanwhile, this
Bright string to led according to the electric current being adjusted arranges the first duty cycle signals, and this first dutycycle can compensate due to curent change
The brightness of the led string being affected.
Brief description
Accompanying drawing described herein is used for providing a further understanding of the present invention, constitutes the part of the application, this
Bright schematic description and description is used for explaining the present invention, does not constitute inappropriate limitation of the present invention.In the accompanying drawings:
Fig. 1 is the schematic diagram of the led driver according to correlation technique；
Fig. 2 is the schematic diagram of the exponential relationship between the voltage of two different led according to correlation technique and electric current；
Fig. 3 is the schematic diagram of the power consumption of two different led strings according to employing Fig. 2 of correlation technique；
Fig. 4 is the schematic diagram of led driver according to embodiments of the present invention；
Fig. 5 is the schematic diagram of the power consumption of according to embodiments of the present invention shown in employing Fig. 2 two difference led string；
And
Fig. 6 is the flow chart of led driving method according to embodiments of the present invention.
Specific embodiment
It should be noted that in the case of not conflicting, the embodiment in the application and the feature in embodiment can phases
Mutually combine.To describe the present invention below with reference to the accompanying drawings and in conjunction with the embodiments in detail.
Lower Fig. 2 is described in detail when extending on many led strings, the led being caused due to the difference manufacturing between led
Heat skewness on driver controller or heat accumulation.
Fig. 2 is the schematic diagram of the exponential relationship between the voltage of according to embodiments of the present invention two difference led and electric current
One, as illustrated in fig. 2, it is assumed that the electric current in each led string is set to 40ma, then led1 must be in one about 2.95 volts of forward direction
Voltage drop runs, and led2 must run in one about 3.26 volts of forward drop simultaneously.Therefore, the forward direction of led1 and led2
There is one about 0.31 volt of difference between voltage drop.Assume there are 10 led with led1 characteristic in a led string, then
Crossing over a led string has the voltage drop of a 29.5v；Assume there are 10 led with led2 characteristic in the 2nd led string, then
Crossing over the 2nd led string has the voltage drop of a 32.6v.
And then, in order to compensate the difference of the voltage drop between led string, the generally passage in the passage belonging to adjustment led string
The voltage drop of actuator.Fig. 3 is the power consumption of according to embodiments of the present invention shown in employing Fig. 2 two difference led string
Schematic diagram, as shown in Figure 3 it is assumed that adjusting output voltage to 33 volts to go here and there 13 and the 2nd led string 14 to obtain by a led
The electric current of 40ma, and assume that the voltage drop crossing over a led string 13 is 29.5v and the voltage drop crossing over the 2nd led string 14 is
32.6v, then the voltage drop on the first transistor 153 in the passage belonging to a led string 13 is 0.1v and passage actuator 152
On voltage drop be 3.4v, and the voltage drop on the transistor seconds 153 in the passage belonging to the 2nd led string 14 be 0.1v and
Voltage drop on second channel actuator 154 is 0.3v.Therefore, the voltage differences of 3.1v are obtained by adjusting passage actuator
Compensate.But meanwhile, the voltage differences of this 3.1v can lead to passage actuator power consumption more than 154 is 40ma × (3.4v+
0.1v) -40ma × (0.3v+0.1v)=124mw.
It is clear that when extending on many led strings, the above-mentioned power consuming can cause on led driver controller more
Heat skewness or heat accumulation.
In order to solve the above problems, embodiments provide a kind of led driver, this led driver can drive
Multiple led strings, make the brightness that each led goes here and there identical.
Fig. 4 is the schematic diagram of led driver according to embodiments of the present invention, as shown in figure 4, including led driver control
Device 41 and power supervisor 43.Below its structure is described in detail.
Power supervisor 41, for multiple led strings 42 offer output voltage in parallel.Wherein, this power supervisor 41
Receives input voltage 44 simultaneously receives the analog voltage of the second digital to analog converter 417 in led driver controller 41, and
There is provided this output voltage according to this analog voltage.
It should be noted that although Fig. 4 only illustrates two led strings, this led driver can drive any amount of
Led goes here and there.Meanwhile, although this led driver controller 41 needs to use with power supervisor 43 simultaneously, this has no effect on this
Led driver controller 41 still as single production and sale, just describes this situation below.
As shown in figure 4, this led driver controller 42 can apply to above-mentioned led driver.This led driver control
Device 42 includes: multiple terminals 411, can connect multiple led strings 42 respectively.Simultaneously for each led string 42, led driver control
Device also includes: passage actuator 412, according to the detection voltage in corresponding led string, adjusts the electric current by led string 42；And
The first transistor 413, is turned on and off led string 42 according to the first duty cycle signals, and the wherein first duty cycle signals are based on logical
Electric current that road actuator 412 is adjusted and determine.
In the embodiment of the present invention, the electric current by led string 42 is adjusted using passage actuator 412, passage can be adjusted and adjust
Voltage drop on section device 412, thus adjusting the power loss on passage actuator 412, and then, many led string 42 extends
When, it is possible to reduce the heat skewness on led driver controller 42 or heat accumulation, solve this led driver control
The temperature of device 42 raises problem.Meanwhile, the embodiment of the present invention is believed to led string 42 setting the first dutycycle according to the electric current being adjusted
Number, this first dutycycle can compensate the led being affected by curent change go here and there 42 brightness.
Based on the led driver controller 42 shown in Fig. 4, the invention provides an example, this example can solve Fig. 3
The problem that the temperature of shown led driver controller 42 raises.With reference to Fig. 5, this example is described in detail.
After Fig. 5 is the minimizing power consumption of according to embodiments of the present invention shown in employing Fig. 2 two difference led string
Schematic diagram, if as shown in figure 5, the electric current going here and there led in passage belonging to 42 brings up to 60ma, would know that leap with reference to Fig. 2
The voltage drop of led string 42 is 32v, simultaneously as the voltage drop on the first transistor 413 is correspondingly improved 0.15v, therefore logical
Voltage drop on road actuator 412 is reduced to 0.85v.Therefore, second channel actuator more than 154 consume power be 60ma ×
(0.85v+0.15v) -40ma × (0.3v+0.1v)=44mw, thus produce major improvement to power consumption.Meanwhile, in Fig. 5
In, always according to the electric current being adjusted, adjust the first duty cycle signals (pwm in 1), that is, adjust the first duty cycle signals (pwm
In 1) to the 66% of former dutycycle, so that the average current of led string 42 keeps constant, and then guarantee the brightness of led string 42
Constant.
In one embodiment, passage actuator 412 includes: transistor seconds 4121, operable with adjust gone here and there by led
42 electric current；And feedback circuit, operable so that detection voltage to be compared with first voltage threshold value set in advance and loud
Transistor seconds 4121 should be controlled in this comparative result.Wherein this feedback circuit may include that the first operational amplifier 4122,
Its in the same direction input be connected with the grid of transistor seconds 4121, reverse input end is connected with first voltage threshold value；First
Digital to analog converter 4123, its input is connected with the outfan of the first operational amplifier 4122；And second operational amplifier
4124, its in the same direction input be connected with the outfan of the first digital to analog converter 4223, reverse input end and transistor seconds
4121 source electrode is connected, and outfan is connected with the grid of transistor seconds 4121.It should be noted that this preferred embodiment
Exemplarily only describe a kind of embodiment that can adjust the electric current by led string 42, in practical application, be capable of this
The other embodiment of function or effect all should include protection scope of the present invention.
And then, feedback circuit also operable so that detection voltage to be compared with second voltage threshold value set in advance, and
In response to this comparative result, control power supervisor 43.Wherein, this feedback circuit may include that the 3rd operational amplifier 4125,
Its in the same direction input be connected with the grid of transistor seconds 4121, reverse input end is connected with second voltage threshold value；Second
Digital to analog converter 417, its input is connected with the outfan of the 3rd operational amplifier 4125, outfan and power supervisor 43
It is connected.This preferred embodiment can ensure that accurately, the output voltage of quickly regulation power supply manager 41.
The embodiment of the present invention additionally provides a kind of led driving method, and the method can be based on above-mentioned led driver controller
And realize.Fig. 6 is the flow chart of led driving method according to embodiments of the present invention, as shown in fig. 6, including the steps
S602 is to step s604.
Step s602, for each led string 42 in multiple led strings 42 in parallel, according to the detection voltage in led string,
Adjust the electric current by led string 42.
Step s604, is turned on and off led string 42 according to the first duty cycle signals, the wherein first duty cycle signals are to be based on
The electric current that adjusted and determine.
In the embodiment of the present invention, first, adjust the electric current by led string 42, the electricity on passage actuator 412 can be adjusted
Pressure drop, thus adjusting the power loss on passage actuator 412, and then, when many led string 42 extends, it is possible to reduce led
Heat skewness on driver controller 42 or heat accumulation, the temperature solving this led driver controller 42 raises
Problem.Secondly, the embodiment of the present invention arranges the first duty cycle signals, this first duty according to the electric current being adjusted to led string 42
Than can compensate the led being affected by curent change go here and there 42 brightness.
In one embodiment, according to the detection voltage in led string, adjust and included by the electric current of led string 42: will detect
Voltage is compared with first voltage threshold value set in advance；In response to this comparative result, transistor seconds 4121 is controlled to adjust
Electric current by led string 42.Wherein, if this comparative result instructed voltage is more than first voltage threshold value, control the second crystal
Pipe 4121 improves the electric current by led string 42.In this preferred embodiment, improve and can be increased in led by the electric current of led string 42
Voltage drop on string 42, because the output voltage that now power supervisor provides is constant, therefore on passage actuator 412
Voltage drop will reduce.Meanwhile, according to circuit characteristic, the amount of the amount comparison with voltage reduction that electric current improves is less.Therefore, above-mentioned raising
First electric current is so that the power loss on led driver controller 42 reduces, thus solving this led driver controller 42
Temperature raise problem.
In one embodiment, said method also includes: detection voltage is carried out with second voltage threshold value set in advance
Relatively；In response to this comparative result, control power supervisor 43 to multiple led strings 42 offer output voltage in parallel.Wherein, such as
Really this comparative result instructed voltage is less than second voltage threshold value, then control power supervisor 43 to carry to multiple led strings 42 in parallel
High output voltage.In this preferred embodiment, by improve the first output voltage and the second output voltage it is ensured that led string 42
It is operated in relatively high voltage levvl, thus ensureing led string 42 enough brightness.
It should be noted that the first duty cycle signals that the present invention refers to are determined based on the electric current being adjusted can be,
The product of the first duty cycle signals and the electric current being adjusted is equal to the product of baseline duty cycle signals and base current.Wherein baseline
Duty cycle signals refer to the duty cycle signals from led driver controller outside input, i.e. pwm in 1 in Fig. 1 and pwm
in2；The electric current that base current is gone here and there by led when referring to using baseline duty cycle signals.
Present invention also offers a preferred embodiment, for describing the led driving method shown in Fig. 6 in detail.This example can
To be divided into two Main Stage: start check and correction stage and free metamorphosis stage.
In the start check and correction stage, led driver controller detects whether there is certain led string, and its detection voltage is less than pre-
The second threshold voltage first setting.If it is present controlling power supervisor 43 to improve output voltage, until there is not this detection
Voltage is less than the led string of second threshold voltage.Subsequently into the free metamorphosis stage.
Due to improving the voltage being added in all led strings it is thus possible to lead to there is its certain led string, its detection voltage is big
In first threshold voltage set in advance (this first threshold voltage is more than this second threshold voltage).If it is present represent should
Led string power consumption is higher.
Therefore, in the free metamorphosis stage, led driver controller detects whether there is above-mentioned led string.If it is present
Led driver controller only improves the electric current on this led string, thus realizing the fall of this led string power consumption as shown in Figure 5
Low.The process circulation of this detection voltage and raising electric current is carried out, until there is not this detection voltage to be more than first threshold electricity
The led string of pressure.
So, using the led driving method of the embodiment of the present invention, it is possible to achieve the detection voltage of led string is in this first threshold
So that each led string has relative optimum current level and minimum power consumption between threshold voltage and this second threshold voltage.
Further, in the above-mentioned free metamorphosis stage it is contemplated that led driver controller may improve this led string
On electric current reach this led string upper current limit, and this led string detection voltage still above this first threshold voltage, then make
For accommodation, the output voltage being added in all led strings can be reduced, so that each led string has relative optimum current level
And minimum power consumption.
In sum, according to the abovementioned embodiments of the present invention. provide a kind of led driver controller, led driver and
Led driving method.The embodiment of the present invention adjusts, using passage actuator, the electric current gone here and there by led, can adjust passage actuator
On voltage drop, thus adjusting the power loss on passage actuator, and then, on many led strings extend when, it is possible to reduce
Heat skewness on led driver controller or heat accumulation, the temperature rising solving this led driver controller is asked
Topic.Meanwhile, the embodiment of the present invention is gone here and there to led according to the electric current being adjusted and is arranged the first duty cycle signals, and this first dutycycle can
To compensate the brightness gone here and there by the led that curent change is affected.
The foregoing is only the preferred embodiments of the present invention, be not limited to the present invention, for the skill of this area
For art personnel, the present invention can have various modifications and variations.All within the spirit and principles in the present invention, made any repair
Change, equivalent, improvement etc., should be included within the scope of the present invention.
Claims (8)
1. a kind of led driver controller, comprising:
Multiple terminals (411,414), can connect multiple led string (42) respectively；
Each led is gone here and there (42), described led driver controller also includes:
Passage actuator (412,415), operable with according to corresponding led string in detection voltage, adjust gone here and there by described led
(42) electric current；And
The first transistor (413), operable to be turned on and off described led string (42), wherein institute according to the first duty cycle signals
Stating the first duty cycle signals is the electric current being adjusted based on described passage actuator (412,415) and determines；
Wherein said passage actuator (412,415) includes:
Transistor seconds (4121,4151), the operable electric current with regulation by described led string (42)；And
Feedback circuit, operable so that described detection voltage to be compared with first threshold voltage set in advance, and respond
Control described transistor seconds (4121,4151) in this comparative result, described feedback circuit is also operable electric will described detect
Pressure is compared with second threshold voltage set in advance, and controls power supervisor (43) in response to this comparative result, its
Described in power supervisor (43) be used for providing output voltage to the plurality of led string (42) in parallel so that all described many
The respective detection voltages of individual led string all increase to no longer less than described second threshold voltage in the start check and correction stage, and with
The free metamorphosis stage afterwards is all not more than described first threshold voltage and is not less than described second threshold voltage；
Wherein said feedback circuit includes:
First operational amplifier (4122,4152), the grid phase of its input and described transistor seconds (4121,4151) in the same direction
Connect, reverse input end is connected with described first threshold voltage；
The outfan of the first digital to analog converter (4123,4153), its input and described first operational amplifier (4122,4152)
It is connected；
Second operational amplifier (4124,4154), the outfan of its input and described first digital to analog converter (4123) in the same direction
It is connected, the source electrode of reverse input end and described transistor seconds (4121,4151) is connected, outfan and described second crystal
The grid of pipe (4121,4151) is connected；
3rd operational amplifier (4125,4155), the grid phase of its input and described transistor seconds (4121,4151) in the same direction
Connect, reverse input end is connected with described second threshold voltage；And
Second digital to analog converter (417), its input is connected with the outfan of described 3rd operational amplifier (4125,4155)
Connect, outfan is connected with described power supervisor (43).
2. led driver controller according to claim 1, wherein said first duty cycle signals and the electric current being adjusted
Product be equal to the product of baseline duty cycle signals and base current.
3. a kind of led driver, comprising:
Led driver controller (41) according to claim 1 and 2；And
Power supervisor (43), for providing output voltage to multiple led string (42) in parallel.
4. a kind of multiple led in parallel are gone here and there using led driver controller according to claim 1 (42) are driven
Method, comprising:
For each led string (42) in described multiple led string (42) in parallel, according to the detection voltage in described led string, adjust
Section is by the electric current of described led string (42), comprising:
Described detection voltage is compared with first threshold voltage set in advance, and in response to this comparative result control with
The related transistor (4121,4151) of described led string (42)；And
Described detection voltage is compared with second threshold voltage set in advance, and controls electricity in response to this comparative result
Source manager (43), wherein said power supervisor (43) is used for providing output voltage to described multiple led string (42) in parallel,
The respective detection voltages making all the plurality of led strings all increase to no longer less than described Second Threshold in the start check and correction stage
Voltage, and all it is not more than described first threshold voltage and not less than described Second Threshold electricity in the subsequent free metamorphosis stage
Pressure；And
It is turned on and off corresponding led string (42) according to the first duty cycle signals, wherein said first duty cycle signals are to be based on
The electric current that adjusted and determine.
5. the method that multiple led string (42) in parallel are driven according to claim 4, is also included: if described
Detection voltage is more than described first threshold voltage, then control the transistor (4121,4151) related to described led string (42) to make
Improve the electric current by described led string (42).
6. the method that multiple led string (42) in parallel are driven according to claim 5, is also included: if described
Led string (42) on electric current reach this led string (42) upper current limit after this led string (42) in described detection voltage still big
In described first threshold voltage, then described power supervisor (43) is controlled to reduce output voltage.
7. the method that multiple led string (42) in parallel are driven according to claim 6, is also included: if described
Detection voltage is less than described second threshold voltage, then control described power supervisor (43) to improve output voltage.
8. the method that multiple led string (42) in parallel are driven according to any one of claim 4 to 7, wherein
The product of described first duty cycle signals and the electric current being adjusted is equal to the product of baseline duty cycle signals and base current.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201210519138.3A CN103857135B (en) | 2012-12-05 | 2012-12-05 | LED driver controller, LED driver and LED driving method |
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| CN201210519138.3A CN103857135B (en) | 2012-12-05 | 2012-12-05 | LED driver controller, LED driver and LED driving method |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2021102214A1 (en) * | 2019-11-21 | 2021-05-27 | Lumileds Llc | Current control for led pixel arrays |
| WO2021102222A1 (en) * | 2019-11-21 | 2021-05-27 | Lumileds Llc | Current control for led pixel arrays |
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| CN102105005A (en) * | 2009-12-16 | 2011-06-22 | 三星电机株式会社 | Apparatus for driving light emitting divice using pulse-width modulatoin |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| WO2021102214A1 (en) * | 2019-11-21 | 2021-05-27 | Lumileds Llc | Current control for led pixel arrays |
| WO2021102222A1 (en) * | 2019-11-21 | 2021-05-27 | Lumileds Llc | Current control for led pixel arrays |
| US11895748B2 (en) | 2019-11-21 | 2024-02-06 | Lumileds Llc | Current control for LED pixel arrays |
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|---|---|
| CN103857135A (en) | 2014-06-11 |
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