CN103093727A - Backlight control signal adjustment method and backlight control signal adjustment device - Google Patents
Backlight control signal adjustment method and backlight control signal adjustment device Download PDFInfo
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- CN103093727A CN103093727A CN2013100243259A CN201310024325A CN103093727A CN 103093727 A CN103093727 A CN 103093727A CN 2013100243259 A CN2013100243259 A CN 2013100243259A CN 201310024325 A CN201310024325 A CN 201310024325A CN 103093727 A CN103093727 A CN 103093727A
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Abstract
The invention discloses a backlight control signal adjustment method and a backlight control signal adjustment device. The backlight control signal adjustment method includes that the frequency of a scanning signal and display parameters of a liquid crystal display (LCD) are obtained; the frequency of a current pulse-width modulation (PWM) signal is determined according to the frequency of the scanning signal; a high electric level part, a low electrical level part and a rising edge triggering moment of the current PWM signal are determined; and a rising edge of a PWM signal in a PWM signal cycle is triggered when the rising edge triggering moment of the current PWM signal arrives, and the PWM signal is output according to the frequency, the high electrical part and the low electrical part of the current PWM. Due to the backlight control signal adjustment method and the backlight control signal adjustment device, phase shift which is between the PWM signal and the scanning signal and caused by the mismatching of the PWM signal and the scanning signal, and clamping pressure variation which is at the two ends of the LCD and caused by the polarity inversion of the PWM signal on liquid crystal glass of the LCD are avoided, and the phenomenon that rolling water ripples emerge on the LCD is effectively prevented.
Description
Technical field
The present invention relates to the liquid crystal technology field, specially refer to backlight control signal method of adjustment and device.
Background technology
At present, liquid crystal TV set has become main flow on the market, and grows up at a high speed.The LCDs great majority of liquid crystal TV set adopt LED or cold cathode fluorescent lamp as backlight, liquid crystal TV set is used for controlling the switch of liquid crystal screen back light source by the pwm signal that the counting control register provides a fixed frequency, and recently adjusts brightness backlight by the duty of adjusting this PWM.The system board of liquid crystal TV set provides sweep signal Vsync to LCDs, and to carry out the scanning of screen-picture, this sweep signal frequency is not a fixed value, and is relevant with the Vsync signal of input.When the pwm signal frequency f that is used for controlling LCD screen backlight that provides of counting control register
PWMThe sweep signal frequency f that provides with system board
VSYNCWhen not mating, there is phase shifts between the two, causes to occur the rolling water ripple phenomenon on LCDs.Even do not exist phase association and frequency related between pwm pulse and Vsync, but due to the code book on the liquid-crystalline glasses of LCDs when the reversal of poles, the slight variation occurs in the cramping at liquid crystal two ends, can cause equally the rolling water ripple phenomenon of whole picture to occur.The appearance of these rolling water ripples has seriously affected beholder's visual effect, and beholder's eyesight has been caused bad impact.
Summary of the invention
Backlight control signal method of adjustment and the device of fundamental purpose of the present invention for providing a kind of water ripples of effectively avoiding rolling to disturb.
The present invention proposes a kind of backlight control signal method of adjustment, comprises step:
Obtain the frequency of sweep signal and the screen parameter of LCDs;
According to the frequency of described sweep signal, determine the frequency of current pwm signal;
According to the screen parameter of described LCDs, determine the triggering moment of the rising edge of the high level part of current pwm signal and low level part and current pwm signal;
When the triggering of the rising edge of current pwm signal arrives constantly, trigger the rising edge of the pwm signal in the pwm signal cycle, and according to frequency, high level part and the low level part of current pwm signal, export described pwm signal.
Preferably, described screen parameter according to LCDs, determine that the step in the triggering moment of the rising edge of the high level part of current pwm signal and low level part and current pwm signal specifically comprises:
According to the screen parameter of LCDs, obtain scanning number of buses Vtotal;
According to default Clock Multiplier Factor PreScale and described scanning number of buses Vtotal, obtain described sweep signal at a pwm signal number of scanning lines M=Vtotal ÷ PreScale in the cycle;
According to default occupy ratio duty and described sweep signal at the number of scanning lines M of a pwm signal in the cycle, acquisition high level number of scanning lines N1=M * duty and low level number of scanning lines N2=M * (1-duty), the corresponding current pwm signal of described high level number of scanning lines N1 is in the high level part of a pwm signal in the cycle, and the corresponding current pwm signal of described low level number of scanning lines N2 is in the low level part of a pwm signal in the cycle;
Described sweep signal is arrived the moment of (i-1) * M+1 horizontal scanning line, be defined as triggering the triggering moment of the rising edge of the pwm signal in i pwm signal cycle.
Preferably, described frequency according to sweep signal, determine that the step of the frequency of current pwm signal specifically comprises:
According to default Clock Multiplier Factor PreScale and the frequency f of described sweep signal
VSYNC, the frequency f of acquisition pwm signal
PWM=PreScale * f
VSYNC
Preferably, described screen parameter according to LCDs, determine that the high level part of current pwm signal and low level partly and after the triggering of the rising edge of current pwm signal step constantly also comprise:
In Preset Time, the frequency that detects described sweep signal whether in default sweep signal frequency threshold scope, whether the frequency of current pwm signal in default pwm signal frequency threshold scope;
When the frequency of described sweep signal exceeds default sweep signal frequency threshold scope, or the frequency of current pwm signal is when exceeding default pwm signal frequency threshold scope, with the triggering of the rising edge of a front pwm signal constantly as the triggering of the rising edge of current pwm signal constantly, with the frequency of the front pwm signal frequency as current pwm signal, with the high level part of the high level of front pwm signal part as current pwm signal, with the low level part of the front pwm signal low level part as current pwm signal.
The present invention also proposes a kind of backlight control signal adjusting gear, comprising:
Acquisition module is used for obtaining the frequency of sweep signal and the screen parameter of LCDs;
Generation module is used for the frequency according to described sweep signal, determines the frequency of current pwm signal; According to the screen parameter of described LCDs, determine the triggering moment of the rising edge of the high level part of current pwm signal and low level part and current pwm signal;
Trigger module is used for triggering the rising edge of the pwm signal in the pwm signal cycle when the triggering of the rising edge of current pwm signal arrives constantly, and according to the frequency of current pwm signal, high level partly and the low level part, exports described pwm signal.
Preferably, described generation module specifically is used for:
According to the screen parameter of LCDs, obtain scanning number of buses Vtotal;
According to default Clock Multiplier Factor PreScale and described scanning number of buses Vtotal, obtain described sweep signal at a pwm signal number of scanning lines M=Vtotal ÷ PreScale in the cycle;
According to default occupy ratio duty and described sweep signal at the number of scanning lines M of a pwm signal in the cycle, acquisition high level number of scanning lines N1=M * duty and low level number of scanning lines N2=M * (1-duty), the corresponding current pwm signal of described high level number of scanning lines N1 is in the high level part of a pwm signal in the cycle, and the corresponding current pwm signal of described low level number of scanning lines N2 is in the low level part of a pwm signal in the cycle;
Described sweep signal is arrived the moment of (i-1) * M+1 horizontal scanning line, be defined as triggering the triggering moment of the rising edge of the pwm signal in i pwm signal cycle.
Preferably, described generation module also specifically is used for:
According to default Clock Multiplier Factor PreScale and the frequency f of described sweep signal
VSYNC, the frequency f of acquisition pwm signal
PWM=PreScale * f
VSYNC
Preferably, described backlight control signal adjusting gear also comprises protection module, is used for:
In Preset Time, the frequency that detects described sweep signal whether in default sweep signal frequency threshold scope, whether the frequency of current pwm signal in default pwm signal frequency threshold scope;
When the frequency of described sweep signal exceeds default sweep signal frequency threshold scope, or the frequency of current pwm signal is when exceeding default pwm signal frequency threshold scope, with the triggering of the rising edge of a front pwm signal constantly as the triggering of the rising edge of current pwm signal constantly, with the frequency of the front pwm signal frequency as current pwm signal, with the high level part of the high level of front pwm signal part as current pwm signal, with the low level part of the front pwm signal low level part as current pwm signal.
The present invention adjusts the output of pwm signal according to the screen parameter of the frequency of sweep signal and LCDs, avoid not mating to cause because of the frequency of pwm signal and sweep signal existing phase shifts or pwm signal to cause the cramping variation at liquid crystal two ends because of reversal of poles between the two on the liquid-crystalline glasses of LCDs, effectively avoided occurring on the LCDs phenomenon of rolling water wave ripple.
Description of drawings
Fig. 1 is the process flow diagram of the first embodiment of backlight control signal method of adjustment of the present invention;
Fig. 2 is the process flow diagram of the second embodiment of backlight control signal method of adjustment of the present invention;
Fig. 3 is the process flow diagram of the 3rd embodiment of backlight control signal method of adjustment of the present invention;
Fig. 4 is the process flow diagram of the 4th embodiment of backlight control signal method of adjustment of the present invention;
Fig. 5 is the structural representation of the first embodiment of backlight control signal adjusting gear of the present invention;
Fig. 6 is the structural representation of the second embodiment of backlight control signal adjusting gear of the present invention.
The realization of the object of the invention, functional characteristics and advantage are described further with reference to accompanying drawing in connection with embodiment.
Embodiment
Should be appreciated that specific embodiment described herein only in order to explain the present invention, is not intended to limit the present invention.
As shown in Figure 1, Fig. 1 is the process flow diagram of the first embodiment of backlight control signal method of adjustment of the present invention.The backlight control signal method of adjustment that the present embodiment is mentioned comprises:
Step S10 obtains the frequency of sweep signal and the screen parameter of LCDs;
The method of the present embodiment is implemented to carry out by the system board of liquid crystal display.Wherein, system board is connected with LCDs, and sweep signal is produced by system board, and the screen parameter can directly be stored in the storer of system board, also can be obtained to LCDs by system board.
Step S20 according to the frequency of sweep signal, determines the frequency of current pwm signal;
For fear of not mating because of the frequency of pwm signal and sweep signal, cause and have phase shifts between the two, therefore, the present embodiment is determined the frequency of current pwm signal according to the frequency of sweep signal, is conducive to avoid occurring on LCDs the phenomenon of rolling water wave ripple.
Step S30 according to the screen parameter of LCDs, determines the triggering moment of the rising edge of the high level part of current pwm signal and low level part and current pwm signal;
For fear of pwm signal on the liquid-crystalline glasses of LCDs because of reversal of poles, cause the cramping variation at liquid crystal two ends, therefore, the present embodiment determine according to the screen parameter of LCDs the high level part of current pwm signal and low level part and current pwm signal rising edge triggering constantly, the situation generation of the water wave ripple of further avoiding rolling.
Step S40 when the triggering of the rising edge of current pwm signal arrives constantly, triggers the rising edge of the pwm signal in the pwm signal cycle, and according to frequency, high level part and the low level part of current pwm signal, output pwm signal.
The pwm signal of the present embodiment is produced by the system board of liquid crystal display, and exports the constant current plate backlight of LCDs to, and the brightness of backlight is controlled.Avoided the existing pwm signal that produces by the counting control register to change suddenly the problem of the TV flicker that causes because of the dutycycle backlight that occurs in the television system handoff procedure.Simultaneously, the present embodiment is adjusted the output of pwm signal according to the screen parameter of the frequency of sweep signal and LCDs, avoid not mating to cause because of the frequency of pwm signal and sweep signal existing phase shifts or pwm signal to cause the cramping variation at liquid crystal two ends because of reversal of poles between the two on the liquid-crystalline glasses of LCDs, effectively avoided occurring on the LCDs phenomenon of rolling water wave ripple.
As shown in Figure 2, Fig. 2 is the process flow diagram of the second embodiment of backlight control signal method of adjustment of the present invention.The present embodiment is described in detail step S20 on basis embodiment illustrated in fig. 1, and step S20 specifically comprises:
Step S21 is according to default Clock Multiplier Factor PreScale and the frequency f of sweep signal
VSYNC, the frequency f of acquisition pwm signal
PWM=PreScale * f
VSYNC
The default Clock Multiplier Factor PreScale of the present embodiment is natural number, for example f
VSYNC=60Hz, PreScale=2, f
PWM=2 * 60=120Hz.The present embodiment is determined the frequency of current pwm signal according to the frequency of sweep signal, can guarantee to keep between pwm signal and sweep signal stable frequency relation, avoid not mating because of the frequency of pwm signal and sweep signal, cause to have phase shifts between the two, be conducive to avoid occurring on LCDs the phenomenon of rolling water wave ripple.
As shown in Figure 3, Fig. 3 is the process flow diagram of the 3rd embodiment of backlight control signal method of adjustment of the present invention.The present embodiment is described in detail step S30 on basis embodiment illustrated in fig. 1, and step S30 specifically comprises:
Step S31 according to the screen parameter of LCDs, obtains scanning number of buses Vtotal;
The system board of the present embodiment according to the screen parameter of LCDs as can be known the vertical busses of image scanning count Vtotal, for example, Vtotal is 1125 row.
Step S32, according to default Clock Multiplier Factor PreScale and scanning number of buses Vtotal, the acquisition sweep signal is the number of scanning lines M=Vtotal ÷ PreScale in the cycle at a pwm signal;
The Clock Multiplier Factor PreScale default according to system board calculates the cycle that scanning M line will produce a PWM waveform.Wherein, default Clock Multiplier Factor PreScale generally gets more than or equal to the result of calculation of 2, M the integer that rounds up.For example, PreScale=2, Vtotal=1125 is capable, M=1125 ÷ 2=563 row, namely every 563 line scan signals are a PWM cycle.
Step S33, according to default occupy ratio duty and sweep signal at the number of scanning lines M of a pwm signal in the cycle, acquisition high level number of scanning lines N1=M * duty and low level number of scanning lines N2=M * (1-duty), the corresponding current pwm signal of high level number of scanning lines N1 is in the high level part of a pwm signal in the cycle, and the corresponding current pwm signal of low level number of scanning lines N2 is in the low level part of a pwm signal in the cycle;
The result of calculation of high level number of scanning lines N1 and low level number of scanning lines N2 is got the integer that rounds up.For example, duty=30%, N1=563 * 30%=169 is capable, N2=563 * (1-30%)=394 row, namely within the sweep time of 563 row, arranged 169 horizontal-scanning intervals is high level, be low level the sweep time of other 394 row.Determine high level part and the low level part of current pwm signal according to the screen parameter of LCDs, can avoid pwm signal on the liquid-crystalline glasses of LCDs because of reversal of poles, cause the cramping variation at liquid crystal two ends.
Step S34 arrives sweep signal moment of (i-1) * M+1 horizontal scanning line, is defined as triggering the triggering moment of the rising edge of the pwm signal in i pwm signal cycle.
The rising edge of the pwm signal of a pwm signal in the cycle is alignd with the rising edge of sweep signal, guarantee between pwm signal and sweep signal the phase relation that keeps stable, the situation of the water wave ripple of further avoiding rolling occurs.
As shown in Figure 4, Fig. 4 is the process flow diagram of the 4th embodiment of backlight control signal method of adjustment of the present invention.The present embodiment has increased the step of frequency protection on basis embodiment illustrated in fig. 1, namely also comprise after step S30:
Step S51 in Preset Time, detects the frequency f of sweep signal
VSYNCF in default sweep signal frequency threshold scope whether
MIN-VSYNC≤ f
VSYNC≤ f
MAX-VSYNC, current pwm signal frequency f
PWMF in default pwm signal frequency threshold scope whether
MIN-PWM≤ f
PWM≤ f
MAX-PWMIf so, execution in step S40; If not, execution in step S52;
Step S52 is in the frequency f of sweep signal
VSYNCExceed default sweep signal frequency threshold scope f
VSYNC＜f
MIN-VSYNCOr f
VSYNC＞f
MAX-VSYNCThe time, or the frequency f of current pwm signal
PWMExceed default pwm signal frequency threshold scope f
PWM＜f
MIN-PWMOr f
VSYNC＞f
MAX-PWMThe time, with the triggering of the rising edge of a front pwm signal constantly as the triggering of the rising edge of current pwm signal constantly, with the frequency of the front pwm signal frequency as current pwm signal, with the high level part of the high level of front pwm signal part as current pwm signal, with the low level part of the front pwm signal low level part as current pwm signal.
the present embodiment is considered following situation, when sweep signal is unstable, can cause the sweep signal frequency to produce transient change, when if the frequency of pwm signal is adjusted along with unsettled sweep signal frequency at this moment, easily produce rolling water wave wave interference, occur for fear of above-mentioned situation, when sweep signal is unstable, keep pwm signal according to frequency and the phase place of the pwm signal of last subnormal output, by the time after the sweep signal frequency stabilization, adjust again frequency and the phase place of pwm signal according to stable sweep signal, further avoided the situation of rolling water wave ripple to occur.
As shown in Figure 5, Fig. 5 is the structural representation of the first embodiment of backlight control signal adjusting gear of the present invention.The backlight control signal adjusting gear that the present embodiment is mentioned comprises:
This device is arranged in the system board of liquid crystal display.Wherein, system board is connected with LCDs, and sweep signal is produced by system board, and the screen parameter can directly be stored in the storer of system board, also can be obtained to LCDs by system board.For fear of not mating because of the frequency of pwm signal and sweep signal, cause and have phase shifts between the two, therefore, the present embodiment is determined the frequency of current pwm signal according to the frequency of sweep signal, is conducive to avoid occurring on LCDs the phenomenon of rolling water wave ripple.For fear of pwm signal on the liquid-crystalline glasses of LCDs because of reversal of poles, cause the cramping variation at liquid crystal two ends, therefore, the present embodiment determine according to the screen parameter of LCDs the high level part of current pwm signal and low level part and current pwm signal rising edge triggering constantly, the situation generation of the water wave ripple of further avoiding rolling.The pwm signal of the present embodiment is produced by the system board of liquid crystal display, and exports the constant current plate backlight of LCDs to, and the brightness of backlight is controlled.Avoided the existing pwm signal that produces by the counting control register to change suddenly the problem of the TV flicker that causes because of the dutycycle backlight that occurs in the television system handoff procedure.Simultaneously, the present embodiment is adjusted the output of pwm signal according to the screen parameter of the frequency of sweep signal and LCDs, avoid not mating to cause because of the frequency of pwm signal and sweep signal existing phase shifts or pwm signal to cause the cramping variation at liquid crystal two ends because of reversal of poles between the two on the liquid-crystalline glasses of LCDs, effectively avoided occurring on the LCDs phenomenon of rolling water wave ripple.
The generation module 20 of the embodiment of the present invention specifically is used for:
According to default Clock Multiplier Factor PreScale and the frequency f of sweep signal
VSYNC, the frequency f of acquisition pwm signal
PWM=PreScale * f
VSYNC
The default Clock Multiplier Factor PreScale of the present embodiment is natural number, for example f
VSYNC=60Hz, PreScale=2, f
PWM=2 * 60=120Hz.The present embodiment is determined the frequency of current pwm signal according to the frequency of sweep signal, can guarantee to keep between pwm signal and sweep signal stable frequency relation, avoid not mating because of the frequency of pwm signal and sweep signal, cause to have phase shifts between the two, be conducive to avoid occurring on LCDs the phenomenon of rolling water wave ripple.
The generation module 20 of the embodiment of the present invention also specifically is used for:
According to the screen parameter of LCDs, obtain scanning number of buses Vtotal;
According to default Clock Multiplier Factor PreScale and scanning number of buses Vtotal, the acquisition sweep signal is the number of scanning lines M=Vtotal ÷ PreScale in the cycle at a pwm signal;
According to default occupy ratio duty and sweep signal at the number of scanning lines M of a pwm signal in the cycle, acquisition high level number of scanning lines N1=M * duty and low level number of scanning lines N2=M * (1-duty), the corresponding current pwm signal of high level number of scanning lines N1 is in the high level part of a pwm signal in the cycle, and the corresponding current pwm signal of low level number of scanning lines N2 is in the low level part of a pwm signal in the cycle;
Sweep signal is arrived the moment of (i-1) * M+1 horizontal scanning line, be defined as triggering the triggering moment of the rising edge of the pwm signal in i pwm signal cycle.
The system board of the present embodiment according to the screen parameter of LCDs as can be known the vertical busses of image scanning count Vtotal, for example, Vtotal is 1125 row.The Clock Multiplier Factor PreScale default according to system board calculates the cycle that scanning M line will produce a PWM waveform.Wherein, default Clock Multiplier Factor PreScale generally gets more than or equal to the result of calculation of 2, M the integer that rounds up.For example, PreScale=2, Vtotal=1125 is capable, M=1125 ÷ 2=563 row, namely every 563 line scan signals are a PWM cycle.The result of calculation of high level number of scanning lines N1 and low level number of scanning lines N2 is got the integer that rounds up.For example, duty=30%, N1=563 * 30%=169 is capable, N2=563 * (1-30%)=394 row, namely within the sweep time of 563 row, arranged 169 horizontal-scanning intervals is high level, be low level the sweep time of other 394 row.Determine high level part and the low level part of current pwm signal according to the screen parameter of LCDs, can avoid pwm signal on the liquid-crystalline glasses of LCDs because of reversal of poles, cause the cramping variation at liquid crystal two ends.The rising edge of the pwm signal of a pwm signal in the cycle is alignd with the rising edge of sweep signal, guarantee between pwm signal and sweep signal the phase relation that keeps stable, the situation of the water wave ripple of further avoiding rolling occurs.
As shown in Figure 6, Fig. 6 is the structural representation of the second embodiment of backlight control signal adjusting gear of the present invention.The present embodiment has increased protection module 40 on basis embodiment illustrated in fig. 5, be used for:
In Preset Time, the frequency that detects sweep signal whether in default sweep signal frequency threshold scope, whether the frequency of current pwm signal in default pwm signal frequency threshold scope;
When the frequency of sweep signal exceeds default sweep signal frequency threshold scope, or the frequency of current pwm signal is when exceeding default pwm signal frequency threshold scope, with the triggering of the rising edge of a front pwm signal constantly as the triggering of the rising edge of current pwm signal constantly, with the frequency of the front pwm signal frequency as current pwm signal, with the high level part of the high level of front pwm signal part as current pwm signal, with the low level part of the front pwm signal low level part as current pwm signal.
the present embodiment is considered following situation, when sweep signal is unstable, can cause the sweep signal frequency to produce transient change, when if the frequency of pwm signal is adjusted along with unsettled sweep signal frequency at this moment, easily produce rolling water wave wave interference, occur for fear of above-mentioned situation, when sweep signal is unstable, keep pwm signal according to frequency and the phase place of the pwm signal of last subnormal output, by the time after the sweep signal frequency stabilization, adjust again frequency and the phase place of pwm signal according to stable sweep signal, further avoided the situation of rolling water wave ripple to occur.
The above is only the preferred embodiments of the present invention; not thereby limit the scope of the claims of the present invention; every equivalent structure or equivalent flow process conversion that utilizes instructions of the present invention and accompanying drawing content to do; or directly or indirectly be used in other relevant technical fields, all in like manner be included in scope of patent protection of the present invention.
Claims (8)
1. a backlight control signal method of adjustment, is characterized in that, comprises step:
Obtain the frequency of sweep signal and the screen parameter of LCDs;
According to the frequency of described sweep signal, determine the frequency of current pwm signal;
According to the screen parameter of described LCDs, determine the triggering moment of the rising edge of the high level part of current pwm signal and low level part and current pwm signal;
When the triggering of the rising edge of current pwm signal arrives constantly, trigger the rising edge of the pwm signal in the pwm signal cycle, and according to frequency, high level part and the low level part of current pwm signal, export described pwm signal.
2. backlight control signal method of adjustment according to claim 1, it is characterized in that, described screen parameter according to LCDs, determine that the step in the triggering moment of the rising edge of the high level part of current pwm signal and low level part and current pwm signal specifically comprises:
According to the screen parameter of LCDs, obtain scanning number of buses Vtotal;
According to default Clock Multiplier Factor PreScale and described scanning number of buses Vtotal, obtain described sweep signal at a pwm signal number of scanning lines M=Vtotal ÷ PreScale in the cycle;
According to default occupy ratio duty and described sweep signal at the number of scanning lines M of a pwm signal in the cycle, acquisition high level number of scanning lines N1=M * duty and low level number of scanning lines N2=M * (1-duty), the corresponding current pwm signal of described high level number of scanning lines N1 is in the high level part of a pwm signal in the cycle, and the corresponding current pwm signal of described low level number of scanning lines N2 is in the low level part of a pwm signal in the cycle;
Described sweep signal is arrived the moment of (i-1) * M+1 horizontal scanning line, be defined as triggering the triggering moment of the rising edge of the pwm signal in i pwm signal cycle.
3. backlight control signal method of adjustment according to claim 2, is characterized in that, described frequency according to sweep signal determines that the step of the frequency of current pwm signal specifically comprises:
According to default Clock Multiplier Factor PreScale and the frequency f of described sweep signal
VSYNC, the frequency f of acquisition pwm signal
PWM=PreScale * f
VSYNC
4. according to claim 2 or 3 described backlight control signal methods of adjustment, it is characterized in that, described screen parameter according to LCDs, determine that the high level part of current pwm signal and low level partly and after the triggering of the rising edge of current pwm signal step constantly also comprise:
In Preset Time, the frequency that detects described sweep signal whether in default sweep signal frequency threshold scope, whether the frequency of current pwm signal in default pwm signal frequency threshold scope;
When the frequency of described sweep signal exceeds default sweep signal frequency threshold scope, or the frequency of current pwm signal is when exceeding default pwm signal frequency threshold scope, with the triggering of the rising edge of a front pwm signal constantly as the triggering of the rising edge of current pwm signal constantly, with the frequency of the front pwm signal frequency as current pwm signal, with the high level part of the high level of front pwm signal part as current pwm signal, with the low level part of the front pwm signal low level part as current pwm signal.
5. a backlight control signal adjusting gear, is characterized in that, comprising:
Acquisition module is used for obtaining the frequency of sweep signal and the screen parameter of LCDs;
Generation module is used for the frequency according to described sweep signal, determines the frequency of current pwm signal; According to the screen parameter of described LCDs, determine the triggering moment of the rising edge of the high level part of current pwm signal and low level part and current pwm signal;
Trigger module is used for triggering the rising edge of the pwm signal in the pwm signal cycle when the triggering of the rising edge of current pwm signal arrives constantly, and according to the frequency of current pwm signal, high level partly and the low level part, exports described pwm signal.
6. backlight control signal adjusting gear according to claim 5, is characterized in that, described generation module specifically is used for:
According to the screen parameter of LCDs, obtain scanning number of buses Vtotal;
According to default Clock Multiplier Factor PreScale and described scanning number of buses Vtotal, obtain described sweep signal at a pwm signal number of scanning lines M=Vtotal ÷ PreScale in the cycle;
According to default occupy ratio duty and described sweep signal at the number of scanning lines M of a pwm signal in the cycle, acquisition high level number of scanning lines N1=M * duty and low level number of scanning lines N2=M * (1-duty), the corresponding current pwm signal of described high level number of scanning lines N1 is in the high level part of a pwm signal in the cycle, and the corresponding current pwm signal of described low level number of scanning lines N2 is in the low level part of a pwm signal in the cycle;
Described sweep signal is arrived the moment of (i-1) * M+1 horizontal scanning line, be defined as triggering the triggering moment of the rising edge of the pwm signal in i pwm signal cycle.
7. backlight control signal adjusting gear according to claim 6, is characterized in that, described generation module also specifically is used for:
According to default Clock Multiplier Factor PreScale and the frequency f of described sweep signal
VSYNC, the frequency f of acquisition pwm signal
PWM=PreScale * f
VSYNC
8. according to claim 6 or 7 described backlight control signal adjusting gears, is characterized in that, also comprises being used for protection module:
In Preset Time, the frequency that detects described sweep signal whether in default sweep signal frequency threshold scope, whether the frequency of current pwm signal in default pwm signal frequency threshold scope;
When the frequency of described sweep signal exceeds default sweep signal frequency threshold scope, or the frequency of current pwm signal is when exceeding default pwm signal frequency threshold scope, with the triggering of the rising edge of a front pwm signal constantly as the triggering of the rising edge of current pwm signal constantly, with the frequency of the front pwm signal frequency as current pwm signal, with the high level part of the high level of front pwm signal part as current pwm signal, with the low level part of the front pwm signal low level part as current pwm signal.
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104851374A (en) * | 2015-06-04 | 2015-08-19 | 深圳康荣电子有限公司 | Air circulation refrigerating advertising player and refrigerating method thereof |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| WO2016074340A1 (en) * | 2014-11-10 | 2016-05-19 | 深圳市华星光电技术有限公司 | Backlight unit and driving method thereof, liquid crystal display device |
| GB2546700A (en) * | 2014-11-10 | 2017-07-26 | Shenzhen China Star Optoelect | Backlight unit and driving method thereof, liquid crystal display device |
| GB2546700B (en) * | 2014-11-10 | 2021-05-12 | Shenzhen China Star Optoelect | Backlight unit, method for driving the backlight unit, and liquid crystal display |
| CN104851374A (en) * | 2015-06-04 | 2015-08-19 | 深圳康荣电子有限公司 | Air circulation refrigerating advertising player and refrigerating method thereof |
| WO2019019865A1 (en) * | 2017-07-27 | 2019-01-31 | 青岛海信电器股份有限公司 | Multi-partition dynamic backlight driving method and display apparatus |
| US10796644B2 (en) | 2017-07-27 | 2020-10-06 | Hisense Visual Technology Co., Ltd. | Method of driving dynamic backlight and display device |
| CN113035136A (en) * | 2019-12-09 | 2021-06-25 | 瑞昱半导体股份有限公司 | Signal processing method for maintaining relative relationship of signals and electronic device thereof |
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| CN103093727B (en) | 2015-11-18 |
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