CN102469645B - Backlight module and control device for backlight module of light-emitting diode - Google Patents
Backlight module and control device for backlight module of light-emitting diode Download PDFInfo
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Abstract
The invention relates to a backlight module and a control device for the backlight module of a light-emitting diode. The control device comprises a finite-state machine, a multi-power unit and a waveform generating unit, wherein an input end of the finite-state machine is connected with a first digital signal; the finite-state machine is used for encoding the first digital signal according to a preset control demand and outputting a plurality of differently encoded third digital signals; the multi-power unit is composed of a plurality of circuit elements; one input end of each of the circuit elements is connected with a plurality of different third digital signals; the other input end of each of the circuit elements is connected with one of a plurality of differently encoded second digital signals and is used for outputting a plurality of differently encoded fourth digital signals; and one input end of the waveform generating unit is connected with the first digital signal while the other input end is connected with the differently encoded fourth digital signals and is used for converting the differently encoded fourth digital signals into a plurality of analog signals.
Description
Technical field
The present invention is about a kind of LED luminous module and LED luminous module adjusting device; Particularly relevant for a kind of before driving LED luminous module, to each passage adjustment of LED luminous module, provide optimal pulse wave width modulation (PWM), make LED luminous module can control with optimal pwm signal each passage of LED luminous module, to reach the object of saving the energy, also can reach LED luminous module simultaneously and in sending out region light-struck, maintain the consistent of brightness and colour.
Background technology
The light emitting module (backlight module) that large scale liquid crystal TV (LCD TV) is used is at present adopted cold cathode fluorescent tube (Cold Cathode Fluorescent Lamp mostly; CCFL) or light-emitting diode (Light Emitting Diode; LED) be the straight according to mode of light source.Because CCFL fluorescent tube is to use mercury (Hg) as luminescent material, and no matter mercury processes in the manufacturing or subsequent recovery the problem that all has environmental protection, and CCFL fluorescent tube must be isolated with outside air simultaneously, could increase its useful life; And, adding LED technology becomes better and approaching perfection day by day, its luminous efficiency has more advantage compared with CCFL fluorescent tube, and LED technology is to its color, brilliance control also elasticity, easily very, therefore, by the formed straight-down negative light emitting module of light-emitting diode, replacing gradually CCFL fluorescent tube becomes the main light-emitting component of light emitting module.
Please refer to 1 Fig. 1, is the schematic diagram of the formed straight-down negative light emitting module of a kind of existing light-emitting diode.As shown in Figure 1, straight-down negative light-emitting device 400 is by a plurality of luminous (401-40n; N=integer) form, and each luminous 401 is formed by a plurality of light-emitting diode 500.Yet, the light-emitting diode of usining as one of major defect of straight-down negative light emitting module is, the brightness of indivedual light-emitting diodes is difficult to reach in full accord, especially when mixing with ruddiness, green glow, blue light-emitting diode three during output white light, the colour temperature of its white light (color temperature) is to be difficult to control.In addition, its brightness of the light-emitting diode of different color light is also not quite similar for the reaction of variations in temperature, and when light-emitting diode was used after a period of time, the temperature of light-emitting diode can raise along with the time, and the luminance difference of indivedual light-emitting diodes can day by day expand; For example, when temperature is risen to temperature when more than 80 ℃ by room temperature, at most, secondly the brightness decay of red light-emitting diode be blue light-emitting diode, then be secondly green light LED.Therefore, this straight-down negative light emitting module that utilizes a plurality of light-emitting diodes to form, it is easily subject to the variation of indivedual light-emitting diodes and affects the even of its colour temperature and brightness.
In addition, in the prior art, be used for driving the analog circuit drive circuit of the light-emitting diode in straight-down negative light emitting module, the control signal mostly triangular wave generator and amplifier being produced inputs in DC-DC converter 600 (DC-DC Converter), to control the unlatching of light-emitting diode or to turn off.Particularly use the DC-DC converter of voltage-dropping type (buck type) or booster type (boost type).Yet, when above-mentioned DC-DC converter 600 is used to drive while having a plurality of formed array of light-emitting diode (Array) that is connected into one, the luminous flux of each light-emitting diode can change because of the deviation of the forward voltage of each light-emitting diode, therefore, cannot effectively control the colour temperature of light emitting diode matrix (LED Array) and brightness evenly.
In addition, for solving the change in voltage of each light-emitting diode, some utilization lookup table mode (look-up table) carries out, however these methods all need to use a large amount of internal memories, this technology cannot be integrated and manufactures in a chips.
Summary of the invention
In order to address the above problem, a main purpose of the present invention is to provide a kind of modulation unit of adjusting pulse bandwidth function that has, in order to the pwm signal of a simulation is converted to digital signal, and after correcting unit is processed, convert the digital controlled signal of proofreading and correct after processing to corresponding analog signal again, make modulation of the present invention unit to form chip with semiconductor technology and control PWM analog signal.
In order to address the above problem, another main purpose of the present invention is to provide a kind of pulse wave width modulation control device of adjusting function that has, in order to the pwm signal of a simulation is converted to digital signal, and after correcting unit is processed, convert the digital controlled signal of proofreading and correct after processing to corresponding analog signal again, make the pulse wave width modulation control device with adjustment function of the present invention to form chip with semiconductor technology and control PWM analog signal.
Another main purpose of the present invention is to provide a kind of control device of adjusting pulse bandwidth function that has, by the information of many corrective loops, make control device can carry out according to the virtual condition of each light-emitting device in LED array light-emitting device the adjustment of pwm signal, with suitable electric current, provide to each light-emitting device, therefore can avoid LED array light emitting device drive bad and cause brightness or colored inconsistent situation.
According to above-mentioned purpose, first the present invention provides a kind of modulation unit of adjusting pulse bandwidth function that has, modulation unit is connected with the second digital signal of one first digital signal and a plurality of different codings, modulation unit comprises: a finite state machine, input is connected with the first digital signal, and the first digital signal is required to encode with a default control, and produce and export the three digital signal of a plurality of different codings; The unit of merit more than, by a plurality of circuit element, formed, the first input end of each circuit element connects from a plurality of different three digital signals, and one second input of each this circuit element and the second digital signal of a plurality of different codings one of them be connected, and export the 4th digital signal of a plurality of different codings; And a wave generating unit, its first input end is connected with the first digital signal, and the second input is connected with the 4th digital signal of a plurality of different codings, and it converts a plurality of analog signals to by the 4th digital signal of a plurality of different codings.
Wherein, this default control requirement is the effective period that an equal proportion reduces input pulse wave width modulation signal.
Wherein, this finite state machine is in parallel processing mode, to produce the three digital signal of the plurality of different coding.
Wherein, those circuit elements in this many merits unit are a multitask selector.
The present invention then provides a kind of control device of adjusting pulse bandwidth function that has, control device is connected with an input pulse wave width modulation signal and many corrective loops, control device comprises: one measures unit, input pulse wave width modulation signal is counted, input pulse bandwidth is converted to first digital signal of a plurality of and exports first digital signal of a plurality of; One correcting unit, is connected and produces the second digital signal of a plurality of different codings with many corrective loops; One modulation unit, its input is connected with first digital signal of a plurality of and the second digital signal of a plurality of different codings, and first digital signal of a plurality of is required to encode with a default control, and requires a plurality of analog signals of output according to controlling.
Wherein, this default control requirement is the effective period that an equal proportion reduces input pulse wave width modulation signal.
Wherein, modulation unit is connected with first digital signal of a plurality of and the second digital signal of a plurality of different codings, modulation unit comprises: a finite state machine, one input end is connected with the first digital signal of the plurality of position, and the first digital signal is required to encode with this default control, and produce and export the three digital signal of a plurality of different codings; The unit of merit more than, by a plurality of circuit element, formed, the first input end of each this circuit element connects from a plurality of different three digital signals, and the second input of each circuit element and the second digital signal of a plurality of different codings one of them be connected, and export the 4th digital signal of a plurality of different codings; And a wave generating unit, its first input end is connected with first digital signal of a plurality of, and the second input is connected with the 4th digital signal of a plurality of different codings, and it converts a plurality of analog signals to by the 4th digital signal of a plurality of different codings.
Wherein, those circuit elements in this many merits unit are a multitask selector.
The present invention provides a kind of light emitting module again, comprising: a voltage conversion device, converts an input voltage to a higher output voltage; One control device, be connected with an input pulse wave width modulation signal and many corrective loops, this control device comprises: one measures unit, input pulse wave width modulation signal is counted, input pulse bandwidth is converted to first digital signal of a plurality of and exports the first digital signal of the plurality of position; One correcting unit, is connected and produces the second digital signal of a plurality of different codings with many corrective loops; One modulation unit, its input is connected with first digital signal of a plurality of and the second digital signal of a plurality of different codings, and first digital signal of a plurality of is required to encode with a default control, and requires a plurality of analog signals of output according to controlling; One current voltage stabilizer, a plurality of analog signals of exporting with control device are connected; Many corrective loops, are connected with correcting unit and current voltage stabilizer; And a LED light-emitting device, by a plurality of LED luminescence units, being formed, each LED luminescence unit is connected with each analog signal.
Wherein, this modulation unit is connected with the first digital signal of the plurality of position and the second digital signal of the plurality of different coding, this modulation unit comprises: a finite state machine, one input end is connected with the first digital signal of the plurality of position, and this first digital signal is required to encode with this default control, and produce and export the three digital signal of a plurality of different codings; One multi-task unit, by a plurality of circuit element, formed, one first input end of each this circuit element connects from the plurality of different three digital signal, and one second input of each this circuit element and the second digital signal of the plurality of different coding one of them be connected, and export the 4th digital signal of a plurality of different codings; An and wave generating unit, one first input end is connected with the first digital signal of the plurality of position, and one second input is connected with the 4th digital signal of the plurality of different coding, and it converts a plurality of analog signals to by the 4th digital signal of the plurality of different coding.
Wherein, those LED luminescence units are LED lamp string.
Via provided by the present invention have to adjust the control device of pulse width modulation function and use originally there is the formed light emitting module of control device of adjusting pulse width modulation function, can avoid driving bad and cause brightness or colored inconsistent situation.
Accompanying drawing explanation
Fig. 1 is the schematic diagram of the formed straight-down negative light emitting module of a kind of existing light-emitting diode;
Fig. 2 is the system block schematic diagram of LED array light emitting module of the present invention;
Fig. 3 is the system block schematic diagram of DPWM modulation of the present invention unit;
Fig. 4 is that DPWM FSM of the present invention carries out digitally coded schematic diagram;
Fig. 5 is the side circuit schematic diagram of many merits of the present invention unit;
[main element symbol description]
10 LED array light emitting modules
100 voltage conversion devices
200 PWM control device
210 PWM measure unit
230 correcting units 230
250 DPWM modulation unit
The finite state machine of 2510 DPWM
2530 multi-task units
2550 wave generating unit
300 current voltage stabilizers
310 corrective loops
400 LED array light-emitting devices
401～40n LED lamp string (LED String)
500 LED elements
600 DC-DC converters
Embodiment
Because the present invention discloses a kind of light-emitting diode (LED) light emitting module adjusting device, particularly relevant for a kind of before driving LED light emitting module, to each passage adjustment of LED light emitting module, provide optimal pulse wave width modulation; Some that wherein used, about the formed light emitting module of LED, LED, current voltage stabilizer, DC-DC converter etc., utilize prior art to reach, therefore in following explanation, do not do complete description.In addition, graphic in following interior literary composition, also not according to the actual complete drafting of relative dimensions, its effect is only being expressed the schematic diagram relevant with feature of the present invention.
In addition, in follow-up explanation, following noun can be replaced with English alphabet, for example: light-emitting diode replaces with PWM_in with the pulse wave width modulation signal that LED replaces, pulse wave width modulation replaces, input with PWM and the pulse wave width modulation with adjustment function replaces with DPWM.
First, refer to Fig. 2, the system block schematic diagram of LED array light emitting module of the present invention.As shown in Figure 2, LED array light emitting module 10 comprises that a voltage conversion device 100, PWM control device 200, a current voltage stabilizer 300 being connected with PWM control device 200 and a LED array light-emitting device 400 being connected with voltage conversion device 100 and current voltage stabilizer 300 form.
As shown in Figure 2, voltage conversion device 100 is in order to convert an input voltage vin to a higher output voltage V out; Wherein this voltage conversion device 100 can be DC-DC converter; Then, the output voltage after conversion is inputed to a formed light-emitting device 400 of LED array, for example a kind of LED array backlight module using in LCD TV; LED array light-emitting device 400 is formed by a plurality of LED element 500, or is formed by 401 of a plurality of LED lamp strings (LED String), and wherein each LED lamp string is formed by a plurality of LED element 500, as shown in Figure 1.Then, LED array light emitting module of the present invention also comprises that has a pulse wave width modulation control device 200 (Dimming PWM Controller who adjusts function; DPWM Controller), be that a PWM_in is converted to a plurality of DPWM control signal (DPWM Channel; DPWM_ch), wherein, PWM_in is provided by the display system that disposes LED array light-emitting device 400; For example: the controller by LCD TV provides; Wherein, PWM control device 200 is comprised of PWM measurement unit 210, correcting unit 230 and DPWM modulation unit 250.Afterwards, DPWM control device 200 exports the DPWM control signal of each simulation after conversion (i.e. the pwm signal of simulation) in current voltage stabilizer 300 (Current Regulator) to, again by current voltage stabilizer 300 by the DPWM control signal of each simulation after suitable processing, the electric current of each passage is inputed in a LED array light-emitting device 400.Outside cause, the pulse wave width modulation control device with adjustment function of the present invention, in order to the pwm signal of a simulation is converted to digital signal, and after correcting unit is processed, convert the digital controlled signal of proofreading and correct after processing to corresponding analog signal again, make the pulse wave width modulation control device of adjusting function that has of the present invention, can form chip with semiconductor technology and control PWM analog signal.
Please refer to again Fig. 2, current voltage stabilizer 300 can be connected the feedback signal of a plurality of predetermined numbers with the correcting unit 230 in DPWM control device 200, to form the interactive corrective loop 310 (current calibration handshake loop) of an electric current; In the present invention, for fear of too complicated explanation, the default feedback signal of the current voltage stabilizer 300 of the present embodiment is 3; Be that the interactive corrective loop 310 of electric current of the present invention is to have 3 feedback signals that current voltage stabilizer 300 is connected with correcting unit 230 with every passage, therefore can make correcting unit 230 produce the signal Ch0_cal[2:0 of N channel correcting]～ChN_cal[2:0], wherein [2:0] represents that each passage has three feedback signals (being 3bits).At this, to emphasize, it can be 2 feedback signals (make correcting unit 230 produce the signal Ch0_cal[1:0 of N channel correctings]～ChN_cal[1:0]), 4 feedback signals (make correcting unit 230 produce the signal Ch0_cal[3:0 of N channel correctings]～ChN_cal[3:0]) or other is greater than four feedback signal persons, and this present invention is not limited for the interactive corrective loop of electric current in the present invention 310; At the present embodiment, be to be preset as 3 feedback signals.Clearly, the signal of these corrections of many is all with digital signaling transmission.
After LED array light-emitting device 400 starts of the present invention, correcting unit 230 is delivered to via 3 feedback signals in the interactive corrective loop 310 of electric current, and the signal that makes correcting unit 230 produce N bars to proofread and correct (be Ch0_cal[2:0]～ChN_cal[2:0]), its main purpose is, via current voltage stabilizer 300, the LED element 500 of each passage in LED array light-emitting device 400 or the current state of a plurality of LED lamp strings 401 are delivered to the correcting unit 230 in PWM control device 200, and make the digital signal that the raw N bars of correcting unit 230 outputs proofread and correct (Ch0_cal[2:0]～ChN_cal[2:0]), and the digital signal that this N bar is proofreaied and correct is delivered in DPWM modulation unit 250, wherein, described current state refers to that the bias state of each luminescence unit (for example: the LED element 500 of each passage or each LED lamp string 401) is not identical, therefore, need to go with different electric currents to drive, in the time of particularly will reaching the object of saving the energy with PWM, need especially to give suitable drive current depending on the state of each luminescence unit, to avoid driving bad, cause brightness or colored inconsistent situation.
In the process of aforesaid electric current interactive corrective loop 310 operations, PWM in DPWM control device 200 measures unit 210 can count (counting) to the signal of PWM_in, to measure DPWM control device 200, be to carry out transmitting digital signals with how many positions, and by these digital signal transfers to DPWM modulation unit 250, to produce a plurality of DPWM control signals (being DPWM_ch0～DPWM_chN), and these DPWM control signals are sent to current voltage stabilizer 300.For example: when the frequency signal (time clock) of LED array light emitting module 10 is 20MHz, and when the signal effective period of PWM_in, (duty cycle) was 1KHz, by after the signal of PWM_in being counted with the frequency signal of LED array light emitting module 10 when PWM measurement unit 210, can several 20,000 time, and while converting binary code to by 20,000, can with 15 represent 20,000 these numerals and with PWM_pulse[14:0] represent.
Then, please refer to Fig. 3, the system block schematic diagram of DPWM modulation of the present invention unit.As shown in Figure 3, DPWM modulation unit comprises finite state machine (the DPWM Finite State Machine of a DPWM; DPWM FSM) 2510; 2530 and one of merit unit more than (Multiplexer) wave generating unit (Waveform Generator) 2550; Wherein, DPWM FSM 2510 can will be measured the digital signal of 15 (be PWM_pulse[14:0]) of unit 210 inputs and according to default pwm signal, control requirement and will carry out digital coding by PWM, this one controls that to require be the effective period of an equal proportion reduction PWM_in; For example: if to require be PWM_in is sequentially reduced while providing luminescence unit 0.4% effective period in default control, DPWM FSM 2510 can sequentially send 8 DPWM digital signals after calibrated (Cal0_DPWM_pulse[14:0]～Cal7_DPWM_pulse[14:0]), and wherein to control be that PWM_in is sequentially reduced to 4% to the DPWM of each correction; Can sequentially to send 8 DPWM digital signals after correction as follows for DPWM FSM 2510:
| 3bits feedback signal | The digital signal of proofreading and correct | Resize ratio falls in PWM |
| 000 | Cal0_DPWM_pulse[14:0] | Do not adjust |
| 001 | Cal1_DPWM_pulse[14:0] | Reduce by 4% |
| 010 | Cal2_DPWM_pulse[14:0] | Reduce by 8% |
| 011 | Cal3_DPWM_pulse[14:0] | Reduce by 12% |
| 100 | Cal4_DPWM_pulse[14:0] | Reduce by 16% |
| 101 | Cal5_DPWM_pulse[14:0] | Reduce by 20% |
| 110 | Cal6_DPWM_pulse[14:0] | Reduce by 24% |
| 111 | Cal7_DPWM_pulse[14:0] | Reduce by 28% |
Now, the corresponding digital signal of the passage of each DPWM FSM 2510 is calculated as follows:
First, if measured 15 signal PWM_pulse[14:0 of unit 210 inputs by PWM] during=101_1011_0111_0100, the numerical value of the decimal system (decimal) after 15 signals convert is 23412.
Then the digital Cal0_DPWM_pulse[14:0, proofreading and correct due to DPWM FSM 2510 the 1st] because do not adjust, therefore the Cal0_DPWM_pulse[14:0 exporting via DPWM FSM 2510] 15 position digital signals be 101_1011_0111_0100; Afterwards this 15 position digital signal is delivered in many merits unit 2530.
Follow again, due to the digital Cal1_DPWM_pulse[14:0 of DPWM FSM 2510 the 2nd passage] be set as PWM_in to reduce by 4%, therefore its metric account form is 23412/1.04=22512 (mantissa rounds up).But because of in digital circuit, the numerical value cannot be being directly reduced after 4% with division, thereby, must calculate the 2nd passage numerical value with DPWM FSM 2510.Its account form is described as follows:
15 position digital signal 101_1011_0111_0100 are had to 1 relatively metric numerical computations out and by each decimal system numerical value all divided by 1.04; This is because in binary system, has the position of actual numerical value for having 1, therefore can obtain
01_1011_0111_0100=23412 (decimal system)
=16384+4096+2048+512+256+64+32+16+4 (decimal system)
23412/1.04＝(16384+4096+2048+512+256+64+32+16+4)/1.04
＝(16384/1.04)+(4096/1.04)+(2048/1.04)+(512/1.04)+
(256/1.04)+(64/1.04)+(32/1.04)+(16/1.04)+(4/1.04)
Follow again, each is carried out to following conversion
16384/1.04＝6384-(16384*(1-(1/1.04)))＝16384-630 (1)
4096/1.04＝4096-(4096*(1-(1/1.04)))＝4096-158 (2)
2048/1.04＝2048-(2048*(1-(1/1.04)))＝2048-79 (3)
512/1.04＝512-(512*(1-(1/1.04)))＝512-20 (4)
256/1.04＝256-(256*(1-(1/1.04)))＝256-10 (5)
64/1.04＝64-(64*(1-(1/1.04)))＝64-2 (6)
32/1.04＝32-(32*(1-(1/1.04)))＝32-1 (7)
16/1.04＝16-(16*(1-(1/1.04)))＝16-1 (8)
4/1.04＝4-(4*(1-(1/1.04)))＝4-0 (9)
Then, by (1)+(2)+(3)+... (9)=>
23412/1.04＝23412-(630+158+79+20+10+1+1)
＝22782-(158+79+20+10+1+1)
＝22624-(79+20+10+1+1)
＝22545-(20+10+1+1)
＝22525-(10+1+1)
＝22515-(1+1)
＝22514-1
＝22513
Now, be converted to after binary one 01_0111_1111_0001 the Cal1_DPWM_pulse[14:0 being exported by DPWM FSM2510 by 22513] 15 position digital signals be 101_0111_1111_0001; Afterwards this 15 position digital signal is delivered in many merits unit 2530.
Other passage according to aforementioned manner, calculate and be converted into 15 position digital signals, can obtain
Cal2_DPWM_pulse[14:0]=23412/1.08=21678 (decimal system)
＝101_0100_1010_1110
Cal3_DPWM_pulse[14:0]=23412/1.12=20904 (decimal system)
＝101_0001_1010_1000
Cal4_DPWM_pulse[14:0]=23412/1.16=20183 (decimal system)
＝100_1110_1101_0111
Cal5_DPWM_pulse[14:0]=23412/1.2=19510 (decimal system)
＝100_1100_0011_0110
Cal6_DPWM_pulse[14:0]=23412/1.24=18881 (decimal system)
＝100_1001_1100_0001
Cal7_DPWM_pulse[14:0]=23412/1.28=18291 (decimal system)
＝100_0111_0111_0011
Afterwards above-mentioned the 2nd to the 8th 15 position digital signals of proofreading and correct that calculate are delivered to respectively in many merits unit 2530.In addition, be stressed that, when DPWM FSM 2510 of the present invention carries out digital coding according to default pwm signal control mode, it can carry out digital coding by 8 corrected values simultaneously, as shown in Figure 4; Certainly, can be also that 8 corrected values are sequentially carried out to digital coding, this present invention is not limited.Moreover, as previously mentioned, the port number N of DPWM FSM 2510 of the present invention can set 8 passages, 16 passages or 32 passages or higher number of channels for, this present invention is not limited, and in specification, just with N passage, do the explanation of embodiment.
Refer again to Fig. 3, when DPWM FSM 2510 has produced after 8 DPWM 15 position digital coding signals after correction, the DPWM digitally encoded signal of these 8 corrections can be delivered to the first input end of many merits unit 2530, the second input of multi-task unit 2530 is to be connected with correcting unit 230 many correction signals that produce (be Ch0_cal[2:0]～ChN_cal[2:0]).
The mode of operation of multi-task unit 2530, please refer to Fig. 5, the side circuit schematic diagram of multi-task unit of the present invention.As shown in Figure 5, multi-task unit 2530 is formed by a plurality of circuit element, and in the present embodiment, this circuit element can be a kind of multitask selector.In addition, many merits of the present invention unit 2530 also can be set 16 passages or 32 passages or higher number of channels for, and this present invention is not limited.8 DPWM signals that the first input end of each the multitask selector in many merits unit 2530 is sent with DPWM FSM 2510 are connected, and in each DPWM signal, comprise 15 position digital coding signals, meanwhile, the second input of multitask selector is to be connected by correcting unit 230 correction signal that produces (Ch0_cal[2:0]～ChN_cal[2:0]) with one; Therefore, when the interactive corrective loop 310 of the electric current of the present embodiment is to be connected with correcting unit 230 with 3 loops and to make after 8 correction signals of correcting unit 230 generations, the second input of each multitask selector is to be connected with a correction signal (Ch_cal[2:0]); Then, each multitask selector, is selected digitally encoded signal for this passage the best (Ch_PWM_pulse[14:0]) and is exported to the first input end of wave generating unit 2550 being selected by the 15 position digital coding signals of 8 of first input end with correction signal.
According to above-mentioned, clearly, multi-task unit 2530 can be to form a plurality of passages by a plurality of multitask selectors, and the quantity of the LED array that the number of channels of this multi-task unit 2530 can will be controlled according to wave generating unit 2550 and determining.For example: in the embodiment of Fig. 5, when multi-task unit 2530 is when controlling N LED array, this multi-task unit 2530 is to form N output channel by N multitask selector, and the DPWM 15 position digital coding signals after 8 corrections that the correction signal that each multitask selector can be inputted according to the second end (Ch_cal[2:0]) is selected to be inputted by first input end, to obtain the digitally encoded signal (Ch_PWM_pulse[14:0]) of one group of the best, afterwards, the best of the N an obtaining passage 15 position digital coding signals (Ch_PWM_pulse[14:0]) are inputed in wave generating unit 2550.
Again to emphasize, in the present embodiment, multiple unit 2530 is to form N output channel by N multitask selector, and 8 DPWM that the first input end of each multitask selector is sent with DPWM FSM 2510 are connected, the second input of many merits unit 2530 is that of being produced in N bar correction signal with correcting unit 230 is connected; Therefore,, when multi-task unit 2530 is individual output channel, one of its connected mode can select the 1st to N multitask selector of multi-task unit 2530 to be sequentially connected with a correction signal; When 2530 operation of many merits unit, each multitask selector can, from 8 15 position digital coding signals of first input end, be selected digitally encoded signal the output of one group of the best by a correction signal; Therefore, when many merits unit 2530 has N output channel, the 15 position digital coding signals that its each passage is exported can be identical or not identical, but it must be to select from 8 15 position digital coding signals of first input end.
Please refer to again Fig. 3, when multi-task unit 2530 has been selected after 15 position digital coding signals of N passage, the digitally encoded signal of this N passage can be delivered to the first input end in wave generating unit 2550, the second input in wave generating unit 2550 is that the digital signal of 15 that provides with measurement unit 210 (be PWM_pulse[14:0]) is connected.Finally, by wave generating unit 2550 according to the digitally encoded signal of N passage of first input end (Ch0_DPWM_pulse[14:0]～ChN_DPWM_pulse[14:0]) and the digital signal of 15 being provided by the second input (be PWM_pulse[14:0]), export after treatment the DPWM control signal (i.e. the pwm signal DPWM_ch0～DPWM_chN of simulation) of N simulation, and the DPWM control signal of these simulations is sent to current voltage stabilizer 300.When the DPWM of each simulation control signal inputs in current voltage stabilizer 300 (Current Regulator), again by current voltage stabilizer 300 by the DPWM control signal of each simulation after suitable processing, the electric current of each passage is inputed in a LED array light-emitting device 400.
When LED array light-emitting device 400 of the present invention is after aforesaid start process, by the interactive corrective loop 310 of electric current and the loop of 230 of correcting units, produced the signal of N bar correction, the signal that this N bar is proofreaied and correct and 8 15 position digital signals exporting through DPWM FSM 2510 are selected after a digitally encoded signal (Ch_PWM_pulse[14:0]) in multi-task unit 2530, the best 15 position digital coding signals after selecting are inputed in wave generating unit 2550, to convert the DPWM control signal of simulation to.The DPWM exporting via DPWM control device 200 again controls signal to current voltage stabilizer 300.Its main purpose is, via current voltage stabilizer 300, the LED element 500 of each passage in LED array light-emitting device 400 or the current state of a plurality of LED lamp strings 401 are delivered to the correcting unit 230 in PWM control device 200, and the digital signal that the raw N bar of correcting unit 230 outputs is proofreaied and correct, and the digital signal that this N bar is proofreaied and correct is delivered in DPWM modulation unit 250; Wherein, described current state refers to that the bias state of each luminescence unit (for example: the LED element 500 of each passage or each LED lamp string 401) is not identical, therefore, need to go with different electric currents to drive; In the time of particularly will reaching the object of saving the energy with PWM, need especially to give suitable drive current depending on the state of each luminescence unit, to avoid driving bad, cause brightness or colored inconsistent situation.
Although the present invention discloses as above with aforesaid preferred embodiment; so it is not in order to limit the present invention; any familiar alike skill person; without departing from the spirit and scope of the present invention; when doing a little change and retouching, therefore scope of patent protection of the present invention must be as the criterion depending on the appended claim person of defining of this specification.
Claims (5)
1. have a control device of adjusting pulse bandwidth function, be connected with an input pulse wave width modulation signal and many corrective loops, it is characterized in that, this control device comprises:
One measures unit, and this input pulse wave width modulation signal is counted, and this input pulse bandwidth is converted to first digital signal of a plurality of and exports the first digital signal of the plurality of position;
One correcting unit, is connected and produces the second digital signal of a plurality of different codings with these many corrective loops; And
One modulation unit, its input is connected with the first digital signal of the plurality of position and the second digital signal of the plurality of different coding, and the first digital signal of the plurality of position is required to encode with a default control, and control and require a plurality of analog signals of output according to this;
Wherein this modulation unit is connected with the first digital signal of the plurality of position and the second digital signal of the plurality of different coding, and this modulation unit comprises:
One finite state machine, one input end is connected with the first digital signal of the plurality of position, and this first digital signal is required to encode with this default control, and produces and export the three digital signal of a plurality of different codings;
The unit of merit more than, by a plurality of circuit element, formed, one first input end of each this circuit element connects from the plurality of different three digital signal, and one second input of each this circuit element and the second digital signal of the plurality of different coding one of them be connected, and export the 4th digital signal of a plurality of different codings; And
A wave generating unit, one first input end is connected with the first digital signal of the plurality of position, and one second input is connected with the 4th digital signal of the plurality of different coding, and it converts a plurality of analog signals to by the 4th digital signal of the plurality of different coding.
2. control device as claimed in claim 1, is characterized in that, it is the effective period that an equal proportion reduces input pulse wave width modulation signal that this default control requires.
3. control device as claimed in claim 1, is characterized in that, those circuit elements in this many merits unit are a multitask selector.
4. a light emitting module, is characterized in that, comprising:
One voltage conversion device, converts an input voltage to a higher output voltage;
One control device, is connected with an input pulse wave width modulation signal and many corrective loops, and this control device comprises:
One measures unit, and this input pulse wave width modulation signal is counted, and this input pulse bandwidth is converted to first digital signal of a plurality of and exports the first digital signal of the plurality of position;
One correcting unit, is connected and produces the second digital signal of a plurality of different codings with these many corrective loops;
One modulation unit, its input is connected with the first digital signal of the plurality of position and the second digital signal of the plurality of different coding, and the first digital signal of the plurality of position is required to encode with a default control, and control and require a plurality of analog signals of output according to this;
One current voltage stabilizer, the plurality of analog signal of exporting with this control device is connected;
Many corrective loops, are connected with correcting unit and this current voltage stabilizer; And
One LED light-emitting device, is comprised of a plurality of LED luminescence units, and each this this analog signal of LED luminescence unit and each is connected;
Wherein this modulation unit is connected with the first digital signal of the plurality of position and the second digital signal of the plurality of different coding, and this modulation unit comprises:
One finite state machine, one input end is connected with the first digital signal of the plurality of position, and this first digital signal is required to encode with this default control, and produces and export the three digital signal of a plurality of different codings;
One multi-task unit, by a plurality of circuit element, formed, one first input end of each this circuit element connects from the plurality of different three digital signal, and one second input of each this circuit element and the second digital signal of the plurality of different coding one of them be connected, and export the 4th digital signal of a plurality of different codings; And
A wave generating unit, one first input end is connected with the first digital signal of the plurality of position, and one second input is connected with the 4th digital signal of the plurality of different coding, and it converts a plurality of analog signals to by the 4th digital signal of the plurality of different coding.
5. light emitting module as claimed in claim 4, is characterized in that, those LED luminescence units are LED lamp string.
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| CN201010535566.6A CN102469645B (en) | 2010-11-04 | 2010-11-04 | Backlight module and control device for backlight module of light-emitting diode |
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| CN201010535566.6A CN102469645B (en) | 2010-11-04 | 2010-11-04 | Backlight module and control device for backlight module of light-emitting diode |
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