CN102244959A - Pulse width modulation unit, circuit and method for driving LED - Google Patents
Pulse width modulation unit, circuit and method for driving LED Download PDFInfo
- Publication number
- CN102244959A CN102244959A CN2011100926302A CN201110092630A CN102244959A CN 102244959 A CN102244959 A CN 102244959A CN 2011100926302 A CN2011100926302 A CN 2011100926302A CN 201110092630 A CN201110092630 A CN 201110092630A CN 102244959 A CN102244959 A CN 102244959A
- Authority
- CN
- China
- Prior art keywords
- selector
- pulse
- led
- pwm unit
- input
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Images
Abstract
The invention discloses a pulse width modulation unit, a circuit thereof and a method thereof for driving an LED. The unit comprises an inverter, a first selector, and a second selector. The inverter has an input terminal and an output terminal; both the first selector and the second selector comprise first input terminals, second input terminals, address terminals and output terminals. The output terminal of the inverter is connected with the first input terminal of the first selector and the input terminal of the inverter is connected with the second input terminal of the first selector; the output terminal of the first selector is connected with the address terminal of the second selector and the address terminal of the first selector is connected with the second input terminal of the second selector; the second input terminal of the first selector is simultaneously connected with a first external pulse; the first input terminal of the second selector is connected with a second external pulse; the second input terminal of the second selector is also simultaneously connected with an external data bit control signal. According to the invention, fewer counters are employed to generate pulse signals with fixed pulse widths; simultaneously, pulse combination can be realized, so that power consumption is reduced.
Description
Technical field
The present invention relates to LED and drive the field, relate in particular to pwm unit, circuit and method that a kind of LED of being used for drives.
Background technology
LED is a kind of solid light source, and when its two ends adds forward voltage, minority carrier in the semiconductor and majority carrier take place compound, and the excess energy of emitting will cause photo emissions.The light intensity of LED is relevant with the average current through it.
Pulse-width modulation mainly is the high level time of modulated pulse signal, promptly is the ON time of LED.Because the frequency of pulse signal is constant, unit period changes the ON time of LED in the time, has promptly changed its average current.
The brightness regulation of LED lamp generally adopts pulse-width modulation, according to needed grey exponent number, a bit of time is divided into the some time sheet, such as 256 grades of GTGs, then is divided into 255 timeslices, forms 0～255 grade of GTG.
So-called " GTG " is meant the rank of LED brightness in fact, and the different gray scales that the LED lamp shows are exactly " GTG ".The red, green, blue three-color LED light of different GTGs concentrates in together, and can form well-rounded color.Three-color LED light is made the control of different shading values, to mix different colors.
Traditional hardware circuit implementation method is the mode that adopts counter, stops after counting down to needed brightness value.For example, 21, if adopt the mode of counter, then need to count down to 21.But, adopt the counter mode to consume too many hardware resource, GTG is got thin more, and then number of counter bits is many more.If the big screen LED control chip, this can consume too many on hardware resource.
Summary of the invention
The technical problem that the present invention mainly solves provides a kind of pwm unit, circuit and method of being used for the LED driving that hardware resource is few and power consumption is very little of using.
For solving the problems of the technologies described above, the technical scheme that the present invention adopts is: the pwm unit that provides a kind of LED of being used for to drive, comprise inverter, first selector and second selector, described inverter has input and output, described first selector and second selector include first input end, second input, address end and output, the output of described inverter connects the first input end of first selector, the input of described inverter connects second input of first selector, the output of described first selector connects the address end of second selector, and the address end of described first selector connects second input of second selector; Second input of first selector also connects the first external pulse, and the first input end of second selector also connects the second external pulse, and second input of second selector connects external data position control signal simultaneously.
Wherein, the described first external pulse and the second external pulse are the fixed pulse signal of one group of predefined distinct pulse widths.
Wherein, described external data position control signal is high level or low level signal.
For solving the problems of the technologies described above, another technical solution used in the present invention is: the pulse-width modulation circuit that provides a kind of LED of being used for to drive, the modulation circuit that the described LED of being used for drives comprise that a plurality of head and the tail of arranging according to data bit connect the above-mentioned pwm unit that LED drives that is used for; The first input end that Gao Yiwei is used for the second selector of the pwm unit that LED drives connects the output that adjacent low level is used for the second selector of the pwm unit that LED drives.
Wherein, described N is used for the pwm unit and (N+1) individual adaptive connection of external pulsion phase that LED drives, and described (N+1) individual external pulse is the fixed pulse signal of one group of predefined distinct pulse widths.
Wherein, described N is used for the pwm unit and N suitable connection of external data position control signal that LED drives, and described N external data position control signal is high level or low level signal.
For solving the problems of the technologies described above, another technical solution used in the present invention is: the pulse duration modulation method that provides a kind of LED of being used for to drive may further comprise the steps:
Select N as the above-mentioned pwm unit that is used for the LED driving according to driving figure place N;
The pwm unit that will be used for the LED driving is arranged in the pulse-width modulation circuit that is used for the LED driving that a plurality of head and the tail connect according to data bit;
Utilize timer and frequency division to produce the fixed pulse signal of (N+1) individual distinct pulse widths, reach according to driving figure place N and produce N data bit control signal;
The fixed pulse signal of distinct pulse widths is used for the first input end that each first selector second input of the pwm unit that LED drives or lowest order be used for the second selector of the pwm unit that LED drives with everybody respectively and is connected;
The data bit control signal be connected with second input that everybody is used for the second selector of the pwm unit that LED drives respectively.
Wherein, connecting a plurality of steps that are used for the pwm unit that LED drives, high one first input end that is used for the second selector of the pwm unit that LED drives is being connected the output that adjacent low level is used for the second selector of the pwm unit that LED drives.
The invention has the beneficial effects as follows: the employing counter that is different from prior art realizes that GTG drives the LED driving pulse-width modulation circuit that shows and used multi-counter, cause the defective of wasting hardware resource and taking the chip design area, the present invention adopts the counter of minority more to produce the pulse signal of fixed pulse width, and utilize the pwm unit pulse signals that is used for the LED driving of a plurality of cascades to carry out logical operation, with a certain position of gradation data and fixed pulse combination, reach the effect of strobe pulse, can accomplish simultaneously that pulse merges, and reduces power consumption.
In addition, traditional circuit is because the upset that pulse can not stop when logical operation will cause power consumption to increase like this, and the present invention can reduce power consumption and avoid short pulse after utilizing the pwm unit paired pulses gating that is used for the LED driving of a plurality of cascades to merge.
Description of drawings
Fig. 1 is the pulse gate mode schematic diagram that the PWM pulse-width modulation of the embodiment of the invention 8 bit binary data is used;
Fig. 2 is needed 7 the fixed pulse oscillograms of the PWM pulse-width modulation of the embodiment of the invention 6 bit binary data;
Fig. 3 is that the embodiment of the invention is used for the pwm unit circuit diagram that LED drives;
Fig. 4 is the pulse-width modulation circuit figure that LED drives that is used for of the embodiment of the invention 6 bit binary data;
Fig. 5 is that the embodiment of the invention 6 bit binary data are 37 data pulse widths modulation waveform figure;
Fig. 6 is the pulse duration modulation method flow chart of steps that LED drives that is used for of the embodiment of the invention.
Embodiment
By describing technology contents of the present invention, structural feature in detail, realized purpose and effect, give explanation below in conjunction with execution mode and conjunction with figs. are detailed.
See also Fig. 1, in the pulse gate mode schematic diagram that the present invention uses, suppose it is the PWM modulation of 8 bit data, can preestablish one group of fixed pulse signal that pulsewidth is different, according to these fixed pulse signals of brightness data difference gating, with regard to not needing each pulse is counted so then.The LED brightness data just is not only a gradation data like this, but the information of certain fixed pulse width of gating.According to said method, by the several fixed pulses that generate, we can combination in any reach different gray scale hybrid modulation.
See also Fig. 2, needed 7 fixed pulses input of 6 bit data pulse-width modulations of the embodiment of the invention, pulse 0 is the constant low level, the one-period of GTG clock is the pulse duration of brightness minimal level, and remaining 6 pulse can be obtained by clock division.The pulse duration of pulse 1 is 1 GTG clock cycle, the pulse duration of pulse 2 is 2 GTG clock cycle, the pulse duration of pulse 3 is 4 GTG clock cycle, the pulse duration of pulse 4 is 8 GTG clock cycle, the pulse duration of pulse 5 is 16 GTG clock cycle, the pulse duration of pulse 6 is 32 GTG clock cycle, respectively corresponding position 0, position 1, position 2, position 3, position 4, position 5, and the pulse input of these six fixed widths is prerequisites that the gray modulation circuit is realized.
See also Fig. 3, the element circuit of pulse-width modulation circuit of the present invention (or saying stage circuit), way circuit are exactly to be made up of several this element circuits.This circuit is a core of the present invention.By this circuit, a certain position of gradation data and fixed pulse combination can be reached the effect of strobe pulse, it can accomplish that pulse merges, and reduces power consumption simultaneously.Traditional circuit, can reduce power consumption and avoid short pulse after pulse merges because the upset that pulse does not stop can cause power consumption to increase.
The element circuit of pulse-width modulation circuit, comprise inverter, first selector and second selector, described inverter has input and output, described first selector and second selector include first input end, second input, address end and output, the output of described inverter connects the first input end of first selector, the input of described inverter connects second input of first selector, the output of described first selector connects the address end of second selector, and the address end of described first selector connects second input of second selector; Second input of first selector also connects the first external pulse, and the first input end of second selector also connects the second external pulse, and second input of second selector connects external data position control signal simultaneously.
Wherein, each element circuit (stage circuit) all is made up of an inverter and two selectors, can realize following algorithm:
1. if data bit is 1, with this 1 level of corresponding length be placed on the back of previous stage output pulse.
2. if data bit is 0, the position of this pulse position controlled and prime output pulse output to be exchanged, this pulse position of controlling is exported 0 level.
See also Fig. 4, the modulation circuit that is used for the LED driving comprises that a plurality of head and the tail of arranging according to data bit connect the above-mentioned pwm unit that LED drives that is used for; The first input end that Gao Yiwei is used for the second selector of the pwm unit that LED drives connects the output that adjacent low level is used for the second selector of the pwm unit that LED drives.The pulse-width modulation that is exactly among Fig. 4 with 6 bit data is the pulse-width modulation circuit of example.This pulse-width modulation circuit is divided into 6 grades, and being linked to each other by 6 stage circuits forms.7 fixed width pulses and 6 bit data are respectively as the input of circuit at different levels.
See also Fig. 5, in one embodiment, tentation data 37=6 ' b100101.See the input/output signal of first order circuit earlier, position 0=1, T1 is directly given in pulse 1, the value " 1 " of fetch bit 0 when T1 is high, T1 gets the value " 0 " of pulse 0 when being low, so just realized 0 of position, obtains the pulse R1 of a minimum brightness width.In the circuit of the second level, position 1=0, T2 is oppositely given in pulse 2, the value " 0 " of fetch bit 1 when T2 is high, T2 gets the waveform of R1 when being low, and the pulse position value of position 1 correspondence is " 0 " like this, and the pulse position value that has kept position 0 correspondence is " 1 ".Next 4 grades of circuit can be analyzed equally, will obtain the pulsewidth waveform that our needed pulse duration is 1+4+32 at last.
See also Fig. 6, the pulse duration modulation method that is used for the LED driving of the embodiment of the invention may further comprise the steps:
Step 101: select N as the above-mentioned pwm unit that is used for the LED driving according to driving figure place N;
Step 102: the pwm unit that will be used for the LED driving is arranged in the pulse-width modulation circuit that is used for the LED driving that a plurality of head and the tail connect according to data bit;
Step 103: utilize timer and frequency division to produce the fixed pulse signal of (N+1) individual distinct pulse widths, reach according to driving figure place N and produce N data bit control signal;
Step 104: the fixed pulse signal of distinct pulse widths is used for the first input end that each first selector second input of the pwm unit that LED drives or lowest order be used for the second selector of the pwm unit that LED drives with everybody respectively and is connected;
Step 105: the data bit control signal be connected with second input that everybody is used for the second selector of the pwm unit that LED drives respectively.
Pulse-width modulation circuit of the present invention has reduced the complexity of logic, has simplified implementation method.Traditional method is that the intensification modulation module is all passed through the counter rapid pulse towards number, the pulse that the present invention changes into by splicing several regular lengths realizes, though the pulse of regular length also is to be dashed by the counter rapid pulse to generate, all LED lamp modulation logic can a shared cover counter.In addition, the invention is not restricted to the GTG progression of LED, 64 grades are suitable for, and 256 grades are suitable for, and 4096 grades or more progression are all suitable.
The above only is embodiments of the invention; be not so limit claim of the present invention; every equivalent structure or equivalent flow process conversion that utilizes specification of the present invention and accompanying drawing content to be done; or directly or indirectly be used in other relevant technical fields, all in like manner be included in the scope of patent protection of the present invention.
Claims (8)
1. one kind is used for the pwm unit that LED drives, it is characterized in that: comprise inverter, first selector and second selector, described inverter has input and output, described first selector and second selector include first input end, second input, address end and output, the output of described inverter connects the first input end of first selector, the input of described inverter connects second input of first selector, the output of described first selector connects the address end of second selector, and the address end of described first selector connects second input of second selector; Second input of first selector also connects the first external pulse simultaneously, and the first input end of second selector connects the second external pulse, and second input of second selector also connects external data position control signal simultaneously.
2. the pwm unit that is used for the LED driving according to claim 1, it is characterized in that: the described first external pulse and the second external pulse are the fixed pulse signal of one group of predefined distinct pulse widths.
3. the pwm unit that is used for the LED driving according to claim 1 is characterized in that: described external data position control signal is overall height level signal or full low level signal.
4. one kind is used for the pulse-width modulation circuit that LED drives, and it is characterized in that: described modulation circuit comprises the pwm unit as each the described LED of being used for driving of claim 1～3 of a plurality of head and the tail connections of arranging according to data bit; The first input end that Gao Yiwei is used for the second selector of the pwm unit that LED drives connects the output that adjacent low level is used for the second selector of the pwm unit that LED drives.
5. the pulse-width modulation circuit that is used for the LED driving according to claim 4, it is characterized in that: described N is used for the pwm unit and (N+1) individual adaptive connection of external pulsion phase that LED drives, and described (N+1) individual external pulse is the fixed pulse signal of one group of predefined distinct pulse widths.
6. the pulse-width modulation circuit that is used for the LED driving according to claim 4, it is characterized in that: described N is used for the pwm unit and N suitable connection of external data position control signal that LED drives, and described N external data position control signal is overall height level signal or full low level signal.
7. one kind is used for the pulse duration modulation method that LED drives, and it is characterized in that, may further comprise the steps:
Select N the pwm unit that is used for the LED driving as claimed in claim 1 according to driving figure place N;
The pwm unit that will be used for the LED driving is arranged in the pulse-width modulation circuit that is used for the LED driving that a plurality of head and the tail connect according to data bit;
Utilize timer and frequency division to produce the fixed pulse signal of (N+1) individual distinct pulse widths, reach according to driving figure place N and produce N data bit control signal;
The fixed pulse signal of distinct pulse widths is used for the first input end that each first selector second input of the pwm unit that LED drives or lowest order be used for the second selector of the pwm unit that LED drives with everybody respectively and is connected;
The data bit control signal be connected with second input that everybody is used for the second selector of the pwm unit that LED drives respectively.
8. the pulse duration modulation method that is used for the LED driving according to claim 7, it is characterized in that:, high one first input end that is used for the second selector of the pwm unit that LED drives is connected the output that adjacent low level is used for the second selector of the pwm unit that LED drives in the step that connects the pwm unit that a plurality of LED of being used for drive.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011100926302A CN102244959A (en) | 2011-04-13 | 2011-04-13 | Pulse width modulation unit, circuit and method for driving LED |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011100926302A CN102244959A (en) | 2011-04-13 | 2011-04-13 | Pulse width modulation unit, circuit and method for driving LED |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN102244959A true CN102244959A (en) | 2011-11-16 |
Family
ID=44962687
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2011100926302A Pending CN102244959A (en) | 2011-04-13 | 2011-04-13 | Pulse width modulation unit, circuit and method for driving LED |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN102244959A (en) |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1932951A (en) * | 2005-09-12 | 2007-03-21 | 中兴通讯股份有限公司 | Non-linear realizing circuit for liquid crystal greyscale |
| CN1932949A (en) * | 2005-09-12 | 2007-03-21 | 中兴通讯股份有限公司 | Circuit for realizing liquid crystal greyscale utilizing frame rate control method |
| US20110204810A1 (en) * | 2010-02-25 | 2011-08-25 | Msilica Inc | Apparatus, circuit and method for automatic phase-shifting pulse width modulated signal generation |
-
2011
- 2011-04-13 CN CN2011100926302A patent/CN102244959A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1932951A (en) * | 2005-09-12 | 2007-03-21 | 中兴通讯股份有限公司 | Non-linear realizing circuit for liquid crystal greyscale |
| CN1932949A (en) * | 2005-09-12 | 2007-03-21 | 中兴通讯股份有限公司 | Circuit for realizing liquid crystal greyscale utilizing frame rate control method |
| US20110204810A1 (en) * | 2010-02-25 | 2011-08-25 | Msilica Inc | Apparatus, circuit and method for automatic phase-shifting pulse width modulated signal generation |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN102497710B (en) | LED phase-shift dimming circuit and method thereof | |
| CN101902861B (en) | LED driving method and LED driving circuit | |
| CN201042097Y (en) | LED circuit for single line cascading multi-level gray full color floating charge | |
| CN107231192A (en) | The data transmission method and LED visible light communication system of double level pulse widths codings | |
| CN105513545B (en) | A kind of back light unit and its driving method, display device | |
| CN103165075B (en) | Driving circuit of light emitting diode and method thereof | |
| KR101790023B1 (en) | Method for controlling light emission of a light emitting device, and a driving system implementing the method | |
| CN102708808A (en) | Method and circuit for driving backlight light emitting diode (LED) lamp of television, and television | |
| CN103813579B (en) | Light emitting diode driving circuit and driving system of light emitting diode | |
| US9271360B2 (en) | LED driving circuit, LED driving device and driving method | |
| CN101640029B (en) | Backlight module, LCD device and light source drive method | |
| CN101930349B (en) | Led scanning control chip | |
| CN114038398A (en) | Gray scale compensation circuit, display device and gray scale compensation method | |
| WO2023126027A2 (en) | Driver circuit of display panel | |
| CN101937638B (en) | Greyscale scanning output method and device | |
| CN102244959A (en) | Pulse width modulation unit, circuit and method for driving LED | |
| TWI820650B (en) | Display device | |
| CN202799283U (en) | Light emitting diode driving circuit and driving system | |
| CN103442482B (en) | LED lighting pulse width modulation drive circuit | |
| CN202025755U (en) | LED chip and display device both packaged by drive circuit in hybrid manner | |
| CN101329835B (en) | LED luminous element for integrated display control device | |
| CN202261959U (en) | Color temperature adjusting driver of light-emitting diode (LED) lamp | |
| CN205793562U (en) | A kind of light emitting diode luminosity control system | |
| CN201251045Y (en) | Light emitting diode lamp and synchronous light emitting diode lamp strip | |
| CN101895194B (en) | Voltage converter, backlight module control system and control method thereof |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C12 | Rejection of a patent application after its publication | ||
| RJ01 | Rejection of invention patent application after publication |
Application publication date: 20111116 |