CN101932159A - Adaptive dimming control method for light emitting diode (LED) - Google Patents
Adaptive dimming control method for light emitting diode (LED) Download PDFInfo
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- CN101932159A CN101932159A CN2009100535922A CN200910053592A CN101932159A CN 101932159 A CN101932159 A CN 101932159A CN 2009100535922 A CN2009100535922 A CN 2009100535922A CN 200910053592 A CN200910053592 A CN 200910053592A CN 101932159 A CN101932159 A CN 101932159A
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Abstract
The invention discloses an adaptive dimming control method for a light emitting diode (LED). The method comprises the following steps of: setting a first counter having N states and recording a first dimming mode state and a second counter having M states and recording the number of the current input pulses, wherein M is greater than N; entering a first pulse analog dimming mode and sending a dimming control signal; counting at the same time by using the first and second counters; when the number counted by the second counter reaches M, switching the current dimming mode to a pulse width modulation (PWM) dimming mode, resetting the first and second counters and keeping the first and second counters in a halted counting state; when the dimming control signal at a first pulse analog dimming termination level is overtime, resetting the second counter; if the current dimming mode is the PWM dimming mode, switching the PWM dimming mode to the first pulse analog dimming mode and switching the state of the first counter to a brightness state corresponding to the original control signal at the first pulse analog dimming termination level in the PWM mode; otherwise, keeping the state of the first counter invariable. The method achieves the effect of adaptively identifying a dimming mode and dimming by using a uniform single module.
Description
Technical field
The present invention relates to the analog integrated circuit design field in the microelectronics, specifically, is a kind of adaptive dimming control method for light emitting diode (LED).
Background technology
LED is luminous by the semiconductor stimulated radiation, its I-V curve as shown in Figure 1, operation interval is between 2 of A among the figure, the B.Specifically, LED is a PN junction, voltage of positively biased on LED, make the LED conducting, flowing through electric current just can be luminous, when LED is reversed voltage bias or the forward bias voltage deficiency so that during the LED conducting, PN junction ends, and does not almost have electric current to flow through LED, so not luminous.Since LED when luminous caloric value seldom, the efficient height, the not mercurous noxious substance that waits belongs to green illumination.For a certain definite LED, the electric current that the brightness of LED and forward conduction flow through it presents positive correlation, and big more LED is bright more for the electric current that flows through, and vice versa.The electric current that flows through LED by the control forward conduction has also just been controlled the brightness of LED.
Two kinds of LED light-dimming methods of main at present existence, a kind of is the PWM dimming controlling method, another kind is a line pulse simulation light-dimming method.
The PWM brightness adjustment control, it is a kind of mode of regulating control LED brightness, its pulse sequence state as shown in Figure 2, principle is the pulsewidth according to a certain frequency of control, be that (DUTYCYCLE is smaller or equal to 1 for the duty ratio DUTYCYCLE of control signal, more than or equal to 0), reach the switch conduction time of control LED in each pulse period.During conducting, LED flows through the setting current value I M that electric current is a drive circuit, and when closing, LED does not have electric current to flow through, and it is 0 that drive circuit is set current value, and the average current that flows through LED like this is DUTYCYCLE*IM.Recently control the average current in a period of time of LED by the duty of control pwm signal, thereby controlled the brightness of LED, the PWM brightness adjustment control ceaselessly sends a certain duty cycle signals, makes the mean flow rate of LED reach requirement, realizes the adjusting to LED brightness.
The electric current of another kind of adjusting LED and the method for brightness are line pulse simulation light modulations, and its time sequence status has been described the pulse of control signal Ctrl and the corresponding relation between the LED electric current I LED as shown in Figure 3.This method is a kind of dimming mode with Digital Logic control LED constant current source, and controller is set with N kind state, and a kind of state drives corresponding to a kind of output current.According to the number of input pulse, the corresponding a kind of state of step-by-step counting is set electric current corresponding to one simultaneously, regulates electric current and the brightness of LED by setting pulse number, and after input pulse above N, state restarts circulation.For a certain specific LED brightness, a line pulse simulation dimming mode reaches the light modulation purpose by sending corresponding limited umber of pulse, and when reaching object brightness, the dimming control signal action finishes, and the control signal level is fixed.After last time light modulation finishes back certain interval of time TDIM, can re-enter the adjusting once more that the LED electric current is carried out in pulse, the initial state of Tiao Jieing is decided on the state machine of logic control once more.
Above-mentioned two kinds of brightness adjustment control modes are separately independently, and in the prior art, that uses PWM brightness adjustment control mode can not a compatible line pulse simulation light modulation, and a line pulse simulation light modulation can not compatible PWM light modulation, and bad adaptability is used inconvenient.
Summary of the invention
The technical problem to be solved in the present invention provides a kind of adaptive dimming control method for light emitting diode (LED), can discern above-mentioned two kinds of dimming modes automatically, no matter make and to load the sort of control signal, can both discern judgement automatically.
In order to achieve the above object, technical scheme of the present invention is as follows:
A kind of adaptive dimming control method for light emitting diode (LED), comprise the steps: that a line light adjusting circuit and PWM light adjusting circuit are set and have first counter of state N kind state, that be used to write down a line light-modulating mode and have second counter M kind state, that be used to write down current input pulse number, wherein M＞N; At first enter a line pulse simulation light-modulating mode and send dimming control signal, described first counter and second counter are counted simultaneously; When second rolling counters forward reached M, switching current light-modulating mode was the PWM light modulation, simultaneously described first counter of zero clearing and second counter and keep first counter and second counter for stopping count status; When dimming control signal is in the minimum time interval that the line pulse simulation light modulation termination level time surpasses the light modulation of twice one line pulse simulations, described second counter of zero clearing; If be the PWM light-modulating mode this moment, then switch to a line pulse simulation light-modulating mode, first counter status switches under the PWM pattern originally control signal at the pairing luminance state of a line pulse simulation light modulation termination level; If be a line pulse simulation light-modulating mode this moment, then continue this pattern and keep first counter status constant.
Adopt adaptive dimming control method for light emitting diode (LED) of the present invention, conjecture earlier is operated under the line pulse mode, if mistake then error correction on the PWM pattern, and can be judged according to real-time dimming control signal back and forth, no matter make to load which kind of control signal, can both discern judgement automatically.Reach the effect of using unified individual module just can discern dimming mode adaptively and carry out light modulation.
Description of drawings
Fig. 1 is the I-V curve synoptic diagram of LED;
Fig. 2 is the pulse sequence view of the PWM light modulation of LED;
Fig. 3 is the time sequence status schematic diagram of the line pulse simulation light modulation of LED;
Fig. 4 is that the state of adaptive dimming control method for light emitting diode (LED) of the present invention switches schematic diagram;
Fig. 5 is the logical schematic of adaptive dimming control method for light emitting diode (LED) of the present invention.
Embodiment
According to Fig. 4 and Fig. 5, provide better embodiment of the present invention, and described in detail below, enable to understand better function of the present invention, characteristics.
Fig. 4 is that the state of adaptive dimming control method for light emitting diode (LED) of the present invention switches schematic diagram.As shown in Figure 4, the basic principle of adaptive dimming control method for light emitting diode (LED) of the present invention is that a line light adjusting circuit and PWM light adjusting circuit are set, and these two circuit all adopt available circuit.Operating state is preset under the line pulse mode, overflows if be used to write down the second counter cnt JUDGE of current input pulse number, then error correction is on the PWM pattern.If judge that TDIM is overtime, then switch back under a line pulse mode.So then can realize the self adaptation light modulation.
The present invention is preset in operating state under the one line pulse mode, is because if operating state is preset under the PWM pattern, can cause losing of brightness adjustment control information, therefore will not adopt.
Fig. 5 is the logical schematic of adaptive dimming control method for light emitting diode (LED) of the present invention.As shown in Figure 5, adaptive dimming control method for light emitting diode (LED) of the present invention is realized as follows.
Step 1 is provided with a line light adjusting circuit and PWM light adjusting circuit and the first counter cnt DIM and the second counter cnt JUDGE.The first counter cnt DIM writes down the state of a line light-modulating mode, and total N kind (present embodiment is got N=16) state, a kind of state be for a LED drive current, i.e. LED brightness.The second counter cnt JUDGE writes down current input pulse number, and total M kind (present embodiment is got M=64) state is guaranteed M＞N wherein.
Particularly, the PWM light adjusting circuit is high conducting, the low shutoff, and the electric current I M that flows through LED during conducting is 10mA.One line pulse simulation light modulation rising edge of one line light adjusting circuit triggers state exchange, 16 step light, first rising edge triggers to such an extent that maximum brightness corresponding current IM is 10mA, that is to say, flow through the LED electric current electric current corresponding under the conducting state in the PWM pattern and equate with high-high brightness state in the line pulse simulation light modulation.Pulse current successively decreases subsequently.The second counter cnt JUDGE has 64 states, and the input pulse above 64 is continuously just overflowed.
Step 2 enters a line pulse simulation light-modulating mode and sends dimming control signal behind the circuit start, the described first counter cnt DIM and the second counter cnt JUDGE count simultaneously.This moment, LED was maximum brightness, corresponding current 10mA.Enter the corresponding current state behind limited rising edge, LED brightness changes synchronously with the value of the first counter cnt DIM.
Step 3, after 64 pulses, second rolling counters forward reaches 64, this moment, to switch current light-modulating mode be the PWM light modulation, LED is 10mA or shutoff with control signal conducting and holding current, its brightness is relevant with the duty of input control signal.After the pwm signal of input changes duty ratio and is 100%, i.e. level overall height, then the LED electric current is 10mA.When switching to the PWM light-modulating mode, can remove the counting of the first counter cnt DIM, also can the zero clearing second counter cnt JUDGE.After the control circuit decision-making system enters the PWM dimming state, continue the input dimming control signal, the first counter cnt DIM and the second counter cnt JUDGE can stop counting, and maintain the original state.
No matter the step 4 control circuit is in a PWM light modulation or a line pulse simulation light modulation, when being in the line pulse simulation light modulation termination level time, control signal surpasses the TDIM time, the second counter cnt JUDGE is cleared, and judges that simultaneously should be operated in a line pulse simulation light-modulating mode this moment.TDIM herein may be defined as the minimum time interval of twice one line pulse simulations light modulation, and PWM light modulation just switches to the judgement time of a line pulse simulation light modulation, and value is 25mS in the present embodiment.
In this step, there are two kinds of situations, promptly judge when should be operated in a line pulse simulation light-modulating mode this moment, originally just be operated under the line pulse simulation light-modulating mode; Perhaps former being operated in before this under the PWM light-modulating mode.If originally be operated in the PWM light-modulating mode, then switch to a line pulse simulation light-modulating mode, first counter status switches under the PWM pattern original control signal at the pairing luminance state of a line pulse simulation light modulation termination level, LED brightness is the pairing brightness of the numerical value of the first counter cnt DIM, and promptly the LED electric current is 10mA.Just use the maximum brightness state equivalent substitute PWM light modulation of a line pulse simulation light modulation, realized that PWM switches back a line pulse simulation light modulation.If originally be operated in a line pulse simulation light-modulating mode, then continue this pattern and keep first counter status constant.
Adaptive dimming control method for light emitting diode (LED) of the present invention can be judged back and forth according to real-time dimming control signal.A kind of adaptive LED dimming mode that can discern above-mentioned two kinds of dimming modes automatically is provided,, can both discerns judgement automatically, thereby regulate LED brightness no matter make and to load the sort of control signal.
Above-described, be preferred embodiment of the present invention only, be not in order to limit scope of the present invention.Adaptive dimming control method for light emitting diode (LED) of the present invention can be realized by multiple circuit.For example, the switch step between two kinds of circuit of the present invention can be controlled by outputing signal to the current source control module to one of the state recognition of counter control.In side circuit, two counters can be realized with the asynchronous 2 systems up counter (ripple carry counter) that resets, also can use N position, M bit synchronization binary system set up counter to realize.The state of two counters is translated by combinational logic circuit, and counter is carried out necessary resetting or set, outputs to the current source control module by a signal, gets final product the switching of implementation pattern.Be that every simple, equivalence of doing according to the claims and the description of the present patent application changes and modification, all fall into the claim protection range of patent of the present invention.
Claims (6)
1. an adaptive dimming control method for light emitting diode (LED) comprises the steps:
One line light adjusting circuit and PWM light adjusting circuit are set and have first counter of state N kind state, that be used to write down a line light-modulating mode and have second counter M kind state, that be used to write down current input pulse number, wherein M＞N;
At first enter a line pulse simulation light-modulating mode and send dimming control signal, described first counter and second counter are counted simultaneously;
When second rolling counters forward reached M, switching current light-modulating mode was the PWM light modulation, simultaneously described first counter of zero clearing and second counter and keep first counter and second counter for stopping count status;
When dimming control signal is in the minimum time interval that the line pulse simulation light modulation termination level time surpasses the light modulation of twice one line pulse simulations, described second counter of zero clearing; If be the PWM light-modulating mode this moment, then switch to a line pulse simulation light-modulating mode, first counter status switches under the PWM pattern originally control signal at the pairing luminance state of a line pulse simulation light modulation termination level; If be a line pulse simulation light-modulating mode this moment, then continue this pattern and keep first counter status constant.
2. a kind of adaptive dimming control method for light emitting diode (LED) as claimed in claim 1 is characterized in that, the electric current electric current corresponding with the high-high brightness state of a line pulse simulation light-modulating mode that flows through LED under the conducting state of PWM pattern equates.
3. a kind of adaptive dimming control method for light emitting diode (LED) as claimed in claim 1 is characterized in that, when light-modulating mode was the PWM light modulation, LED brightness was with the change in duty cycle of pwm signal.
4. a kind of adaptive dimming control method for light emitting diode (LED) as claimed in claim 1 is characterized in that, each of described N kind state kind is corresponding to a LED brightness.
5. a kind of adaptive dimming control method for light emitting diode (LED) as claimed in claim 1 is characterized in that, when light-modulating mode was a line pulse simulation light-modulating mode, LED brightness changed synchronously with the value of first counter.
6. a kind of adaptive dimming control method for light emitting diode (LED) as claimed in claim 1 is characterized in that, a described line pulse simulation light modulation rising edge triggers state exchange, and first rising edge triggers and obtains maximum brightness, and pulse current successively decreases subsequently.
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| Application Number | Priority Date | Filing Date | Title |
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| CN200910053592.2A CN101932159B (en) | 2009-06-23 | 2009-06-23 | Adaptive dimming control method for light emitting diode (LED) |
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| CN200910053592.2A CN101932159B (en) | 2009-06-23 | 2009-06-23 | Adaptive dimming control method for light emitting diode (LED) |
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| CN101932159B CN101932159B (en) | 2014-03-12 |
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Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102159009A (en) * | 2011-03-17 | 2011-08-17 | 上海韦尔半导体股份有限公司 | White light LED (light-emitted diode)-line pulse dimming circuit and dimming method |
| CN103379711A (en) * | 2012-04-23 | 2013-10-30 | Ad技术有限公司 | LED lighting device |
| CN106793328A (en) * | 2017-01-06 | 2017-05-31 | 大连工业大学 | Based on adjustable selection light modulating device and its method for peak point current |
| CN107371300A (en) * | 2017-09-18 | 2017-11-21 | 合肥贯硕信息科技有限公司 | A kind of antinoise LED light source dimming control system |
| CN108882465A (en) * | 2018-08-13 | 2018-11-23 | 上海艾为电子技术股份有限公司 | One line light-dimming method, circuit, chip and system |
| CN109688661A (en) * | 2018-12-26 | 2019-04-26 | 珠海美彤科技有限公司 | Phase-cut dimming method and light modulator after a kind of pulse is silicon-controlled |
| CN112435625A (en) * | 2019-08-06 | 2021-03-02 | 隆达电子股份有限公司 | Pixel circuit and driving method |
| CN112788815A (en) * | 2019-11-04 | 2021-05-11 | 海信视像科技股份有限公司 | Display device and power supply circuit |
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| JP2002119062A (en) * | 2000-10-03 | 2002-04-19 | Hitachi Ltd | Method and apparatus for pulse width modulation and power converter |
| CN1467700A (en) * | 2002-07-11 | 2004-01-14 | 中强电子股份有限公司 | Brightness regulating method and equipment for LCD |
| CN101060752A (en) * | 2006-04-20 | 2007-10-24 | 中强电子股份有限公司 | A multi-lamp dimming control method for the cold cathode lamp tube |
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2009
- 2009-06-23 CN CN200910053592.2A patent/CN101932159B/en not_active Expired - Fee Related
Patent Citations (3)
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| JP2002119062A (en) * | 2000-10-03 | 2002-04-19 | Hitachi Ltd | Method and apparatus for pulse width modulation and power converter |
| CN1467700A (en) * | 2002-07-11 | 2004-01-14 | 中强电子股份有限公司 | Brightness regulating method and equipment for LCD |
| CN101060752A (en) * | 2006-04-20 | 2007-10-24 | 中强电子股份有限公司 | A multi-lamp dimming control method for the cold cathode lamp tube |
Cited By (15)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102159009A (en) * | 2011-03-17 | 2011-08-17 | 上海韦尔半导体股份有限公司 | White light LED (light-emitted diode)-line pulse dimming circuit and dimming method |
| CN102159009B (en) * | 2011-03-17 | 2013-11-06 | 上海韦尔半导体股份有限公司 | White light LED (light-emitted diode)-line pulse dimming circuit |
| CN103379711A (en) * | 2012-04-23 | 2013-10-30 | Ad技术有限公司 | LED lighting device |
| CN103379711B (en) * | 2012-04-23 | 2015-06-03 | Ad技术有限公司 | LED lighting device |
| CN106793328A (en) * | 2017-01-06 | 2017-05-31 | 大连工业大学 | Based on adjustable selection light modulating device and its method for peak point current |
| CN107371300B (en) * | 2017-09-18 | 2018-10-23 | 合肥贯硕信息科技有限公司 | A kind of antinoise LED light source dimming control system |
| CN107371300A (en) * | 2017-09-18 | 2017-11-21 | 合肥贯硕信息科技有限公司 | A kind of antinoise LED light source dimming control system |
| CN108882465A (en) * | 2018-08-13 | 2018-11-23 | 上海艾为电子技术股份有限公司 | One line light-dimming method, circuit, chip and system |
| CN109688661A (en) * | 2018-12-26 | 2019-04-26 | 珠海美彤科技有限公司 | Phase-cut dimming method and light modulator after a kind of pulse is silicon-controlled |
| CN112435625A (en) * | 2019-08-06 | 2021-03-02 | 隆达电子股份有限公司 | Pixel circuit and driving method |
| US11132936B2 (en) | 2019-08-06 | 2021-09-28 | Lextar Electronics Corporation | Pixel circuit and driving method |
| CN112435625B (en) * | 2019-08-06 | 2022-03-15 | 隆达电子股份有限公司 | Pixel circuit and driving method |
| US11495169B2 (en) | 2019-08-06 | 2022-11-08 | Lextar Electronics Corporation | Pixel circuit |
| CN112788815A (en) * | 2019-11-04 | 2021-05-11 | 海信视像科技股份有限公司 | Display device and power supply circuit |
| CN112788815B (en) * | 2019-11-04 | 2022-11-08 | 海信视像科技股份有限公司 | Display device and power supply circuit |
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| CN101932159B (en) | 2014-03-12 |
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