CN102833905A

CN102833905A - PWM (pulse width modulation) dimming method and device for LED (light-emitting diode)

Info

Publication number: CN102833905A
Application number: CN2011101720129A
Authority: CN
Inventors: 王炳; 姚庆辉; 唐小祥; 张磊磊
Original assignee: BSH Electrical Appliances Jiangsu Co Ltd
Current assignee: BSH Electrical Appliances Jiangsu Co Ltd
Priority date: 2011-06-17
Filing date: 2011-06-17
Publication date: 2012-12-19

Abstract

The invention provides a PWM (pulse width modulation) dimming method for an LED (light-emitting diode). The PWM dimming method comprises the following steps: starting a first timer in an interrupt mode and a second timer in a free counting mode of a single chip microcomputer; making statistics on the number of interrupts of the first timer and count values of the second timer during the brightness change stage of the LED; performing at least one zero clearing on the count values of the second timer during the statistical process; and comparing the number of interrupts with the count values in real time, and outputting a PWM wave the level value of which changes along with the comparison result, wherein the PWM wave is applied to the LED for regulating the brightness of the LED. The invention further provides a dimming device corresponding to the method. The PWM dimming method and device for the LED disclosed by the invention can solve the problem of few PWM output ports of the existing cheap single chip microcomputer.

Description

The PWM light-dimming method and the device that are used for LED

Technical field

The present invention relates to the light regulating technology of LED, relate in particular to PWM light-dimming method and the device of a kind of LED of being used for.

Background technology

Along with the application of LED more and more widely, the control of LED is seemed more and more important, not only to carry out switch control to LED, also to carry out brilliance control to the LED light modulation.

Can know that from the V-I characteristic of LED its curve is non-linear, the voltage of 0.1V can cause 100～200mA change in current, and is wayward; Therefore, LED is considered to Current Control property element.Existing LED light modulation generally realizes that through PWM PWM (Pulse Width Modulation) is a pulse width modulating signal, and " width " wherein is exactly the time of the high level of pulse.It is the time through the high level that changes pulse, the i.e. ON time of LED that pwm signal is regulated LED brightness.Sort signal is regulated the average current that brightness is equivalent to regulate LED, so electric current can change.

Prior PWM output generally is to realize that through the ready-made PWM delivery outlet of single-chip microcomputer for example model is the single-chip microcomputer of STC89C52RC.Yet; The PWM delivery outlet number of ready-made single-chip microcomputer is generally all limited, can't realize the brightness adjustment control of LED multi-path, and the PWM delivery outlet is not when doing the use of output PWM ripple in addition; Can be used as common input/output port; Therefore, this type of single-chip microcomputer is in use found to have been taken by other module through regular meeting, for example electric machine controller, buzzer etc.Existing single-chip microcomputer also has some PWM delivery outlets that multichannel is arranged, but price general charged is more expensive.

In view of this, be necessary to propose PWM light-dimming method and the device of a kind of LED of being used in fact, solve the few problem of existing low-cost SCM PWM delivery outlet.

Summary of the invention

The problem that the present invention solves is PWM light-dimming method and the device that proposes a kind of LED of being used for, and solves the few problem of existing low-cost SCM PWM delivery outlet.

For addressing the above problem, the present invention provides the PWM light-dimming method of a kind of LED of being used for, comprising:

Start the first timer that is in interrupt mode and the second timer that is in free count mode of single-chip microcomputer;

Statistics is in the interruption times of the said first timer of LED brightness changes phase and the count value of said second timer; In said statistic processes, the count value of said second timer is carried out at least zero clearing;

Real-time more said interruption times and count value, the PWM ripple that the output level value changes with said comparative result; Wherein, said PWM ripple is used to be applied to LED to regulate its brightness.

Alternatively, said first timer is set to per second interruption N time; Said second timer is every at a distance from very first time T ₃Counting increases by 1, zero clearing when the second timer counting arrives the first value M, the inverse of said N and said T ₃* the ratio of M is at least greater than 1.

Alternatively, said light-dimming method also comprises:

Count value C with the second timer of adding up ₂Interruption times C with first timer ₁Be adjusted into C respectively ₂* p and C ₁* u; Said p is second timer adjustment coefficient, and said u is first timer adjustment coefficient;

Realize said real-time more said interruption times and count value through following step, the PWM ripple that the output level value changes with said comparative result:

The count value C of more adjusted second timer ₂* whether p is less than the interruption times C of adjusted first timer ₁* u;

LED is current to be in from secretly to bright stage the time, if C ₂* p＜C ₁* u, then the PWM ripple is exported second level, otherwise exports first level;

LED is current when being in from bright to dark the stage, if C ₂* p＜C ₁* u, then the PWM ripple is exported first level, otherwise exports second level; Said first level is the level that extinguishes LED, and said second level is a level of lighting LED.

Alternatively, in the count value process of the interruption times of the said first timer of said statistics and said second timer, the interruption times of the said first timer of statistics is carried out a zero clearing.

Alternatively, LED is from secretly to bright stage the time, and the first timer interruption times counts on N*T ₁The time zero clearing, during the stage, the first timer interruption times counts on N*T from bright to dark ₂The time zero clearing; Said T ₁For LED from dark to bright required time, said T ₂For LED from bright to the dark required time.

Alternatively, said light-dimming method also comprises: said first timer is from secretly counting down to N*T to bright process ₁The time, the time that the PWM ripple is exported second level is set, LED gets into the complete bright stage, after the time of output second level of lasting said setting arrives, gets into the process from bright to dark; Do not count N*T ₁The time, carry out said real-time more said interruption times and count value, the PWM ripple step that the output level value changes with said comparative result.

Alternatively, also comprise: said first timer is fallen into a trap to N*T in process from bright to dark ₂The time, the time that the PWM ripple is exported first level is set, LED gets into the complete dark stage, after the time of output first level of lasting said setting arrives, gets into from dark to bright process; Do not count N*T ₂The time, carry out said real-time more said interruption times and count value, the PWM ripple step that the output level value changes with said comparative result.

Alternatively, the acquisition methods of said p and said u is: LED is from secretly to bright process, M*p=N*u*T ₁LED from bright to dark in the process, M*p=N*u*T ₂

Alternatively, said T ₃Be far smaller than the inverse of said N.

Alternatively, said T ₃Inverse be far longer than the first value M.

Alternatively, said LED is a two-way, and said light-dimming method comprises: the first timer that is in interrupt mode and the second timer that is in free count mode that start single-chip microcomputer;

Statistics is in the interruption times of the said first timer of the first paths of LEDs brightness changes phase and the count value of said second timer; In said statistic processes, the count value of said second timer is carried out at least zero clearing;

Statistics is in the interruption times of the said first timer of the second paths of LEDs brightness changes phase and the count value of said second timer; In said statistic processes, the count value of said second timer is carried out at least zero clearing;

The PWM light-dimming method of first paths of LEDs comprises: the interruption times and the count value of the more said first paths of LEDs brightness changes phase, and the output level value forms the first via PWM ripple that changes with said comparative result; Wherein, said first via PWM ripple is used to be applied to first paths of LEDs to regulate its brightness;

Get into the PWM light-dimming method of second paths of LEDs after the output level value; The PWM light-dimming method of said second paths of LEDs comprises: the interruption times and the count value of the more said second paths of LEDs brightness changes phase, and the output level value forms the second road PWM ripple that changes with said comparative result; Wherein, said the second road PWM ripple is used to be applied to second paths of LEDs to regulate its brightness.

Alternatively, get into the PWM light-dimming method of first via LED after the PWM light-dimming method output level value of said second paths of LEDs.

Alternatively, the PWM light-dimming method of said first paths of LEDs also comprises:

LED is current when being in from bright to dark the stage, if C ₂* p＜C ₁* u, then the PWM ripple is exported first level, otherwise exports second level; Said first level is the level that extinguishes LED, and said second level is a level of lighting LED;

The PWM light-dimming method of said second paths of LEDs also comprises:

Count value C with the second timer of adding up ₂₁Interruption times C with first timer ₁₂Be adjusted into C respectively ₂₁* p ' and C ₁₂* u '; Said p ' is second timer adjustment coefficient, and said u ' is first timer adjustment coefficient;

The count value C of more adjusted second timer ₂₁* whether p ' is less than the interruption times C of adjusted first timer ₁₂* u ';

Second paths of LEDs is current to be in from secretly to bright stage the time, if C ₂₁* p '＜C ₁₂* u ', then the PWM ripple is exported second level, otherwise exports first level;

Second paths of LEDs is current when being in from bright to dark the stage, if C ₂₁* p '＜C ₁₂* u ', then the PWM ripple is exported first level, otherwise exports second level; Said first level is the level that extinguishes second paths of LEDs, and said second level is a level of lighting second paths of LEDs.

Alternatively, statistics also comprises in the interruption times of the said first timer of the second paths of LEDs brightness changes phase and the count value step of said second timer: the interruption times of said first timer to statistics is carried out a zero clearing.

Alternatively, from secretly to bright stage the time, the first timer interruption times counts on N*T at second paths of LEDs ₄The time zero clearing, during the stage, the first timer interruption times counts on N*T from bright to dark ₅The time zero clearing; Said T ₄Be second paths of LEDs from dark to bright required time, said T ₅Be second paths of LEDs from bright to the dark required time.

Alternatively, the acquisition methods of said p ' and said u ' is: second paths of LEDs is from secretly to bright process, M*p '=N*u ' * T ₄Second paths of LEDs from bright to dark in the process, M*p '=N*u ' * T ₅

Alternatively, said light-dimming method also comprises: said first timer is from secretly falling into a trap to N*T to bright process ₄The time, the time that the PWM ripple is exported second level is set, second paths of LEDs gets into the complete bright stage, after the time of output second level of lasting said setting arrives, gets into the process from bright to dark; Do not count N*T ₄The time, carry out the interruption times and the count value of the said second paths of LEDs brightness changes phase, the output level value forms the second road PWM ripple step that changes with said comparative result.

Alternatively, said light-dimming method also comprises: said first timer is fallen into a trap to N*T in process from bright to dark ₅The time, the time that the PWM ripple is exported first level is set, second paths of LEDs gets into the complete dark stage, after the time of output first level of lasting said setting arrives, gets into from dark to bright process; Do not count N*T ₅The time, carry out the interruption times and the count value of the said second paths of LEDs brightness changes phase, the output level value forms the second road PWM ripple step that changes with said comparative result.

Alternatively; Said light-dimming method also comprises Third Road LED; Export the PWM light-dimming method that gets into Third Road LED behind the level value of second paths of LEDs, statistics is in the interruption times of the said first timer of Third Road LED brightness changes phase and the count value of said second timer; In said statistic processes, the count value of said second timer is carried out at least zero clearing;

The PWM light-dimming method of Third Road LED comprises: the interruption times and the count value of more said Third Road LED brightness changes phase, and the output level value forms the Third Road PWM ripple that changes with said comparative result; Wherein, said Third Road PWM ripple is used to be applied to Third Road LED to regulate its brightness;

Get into the PWM light-dimming method of first via LED behind the level value of output Third Road LED.

The present invention also provides the PWM light modulating device of a kind of LED of being used for, comprising:

Single-chip microcomputer, said single-chip microcomputer comprises: first timer, second timer, first zero clearing are provided with device; Said first timer is used for per second to interrupt N time, and LED is in the brightness changes phase, adds up the interruption times of said first timer, and zero clearing when counting first clear value; Second timer is used for freely counting, and LED is in from secretly to the bright stage or from bright to dark the phase process, and is every at a distance from very first time T ₃Counting increases by 1, zero clearing when counting arrives the first value M; Said first zero clearing is provided with device and is applicable at LED from secretly to bright process, being set to N*T ₁, from bright to dark, be set to N*T in the process ₂, said T ₁For LED from dark to bright required time, said T ₂For LED from bright to the dark required time;

The pwm signal generator comprises: the current phase acquisition device of living in of LED and first comparator; Said first comparator is applicable to that with said first timer, second timer, first zero clearing device being set links to each other, and is used for the count value C of more adjusted second timer ₂* whether p is less than the interruption times C of adjusted first timer ₁* u; Said C ₂Be the count value of second timer, said C ₁Be the interruption times of first timer, said p is second timer adjustment coefficient, and said u is first timer adjustment coefficient; When the result of said first comparator for being, and the current phase acquisition device of living in of LED obtains the result for from secretly when bright, the pwm signal generator is exported second level, otherwise exports first level; When the result of said first comparator for being, and the current phase acquisition device of living in of LED obtains the result for from bright to dark the time, the pwm signal generator is exported first level, otherwise exports second level; Said first level is the level that extinguishes LED, and said second level is a level of lighting LED.

Alternatively, said light modulating device also comprises: first collector, be connected with the pwm signal generator with first timer, and be used to gather the time that the PWM ripple is exported second level, said first timer is from secretly falling into a trap to N*T to bright process ₁The time, LED gets into the complete bright stage, after the time of output second level of lasting said setting arrives, gets into the process from bright to dark.

Alternatively, said light modulating device also comprises: second collector, be connected with the pwm signal generator with first timer, and be used to gather the time that the PWM ripple is exported first level, said first timer is fallen into a trap to N*T in process from bright to dark ₂The time, LED gets into the complete dark stage, after the time of output first level of lasting said setting arrives, gets into from dark to bright process.

Alternatively, said light modulating device also comprises: p and u getter, link to each other with said first comparator, and be used for LED from secretly to bright process, according to M*p=N*u*T ₁Obtain p, u value; From bright to dark in the process, according to M*p=N*u*T ₂Obtain p, u value.

Compared with prior art, the present invention has the following advantages:

The duty ratio of utilizing the counts of interruption times and second timer of the first timer of single-chip microcomputer to regulate the PWM ripple, said PWM ripple is applied to LED and goes up through changing the voltage of LED, carries out bright dark control; Use hardware is simple; Code is few, and computing is fast, can realize the brightness adjustment control of LED multi-path;

Further, first timer is set to per second and interrupts N time, and the statistics first timer from dark interruption times to the bright process, and is counted N*T at LED ₁The time zero clearing, statistics and is counted N*T in LED interruption times in the process from bright to dark ₂The time zero clearing, T ₁For LED from dark to bright required time, T ₂For LED from bright to the dark required time; Second timer is set to free counting mode and every at a distance from very first time T ₃Counting increases by 1, zero clearing when counting arrives the first value M; The value C of more adjusted afterwards second timer ₂* whether p is less than the interruption times C of adjusted first timer ₁* u; According to C ₂* p and C ₁* the level of LED is lighted or extinguished to the magnitude relationship correspondence of u, thereby the duty ratio that changes the PWM ripple reaches the bright dark purpose of regulating LED; So can realize the output of single channel PWM ripple, promptly realize the brightness adjustment control of single LED;

Further, after the output of single channel PWM ripple, i.e. after the first via PWM ripple output, utilize C ₂₁The statistics second timer second paths of LEDs from secretly to bright or from bright to dark count value the process, C ₁₂The statistics second timer second paths of LEDs from secretly to bright or from bright to dark interruption times the process, identical with the light-dimming method of single LED, with the count value C of second timer ₂₁Be adjusted into C ₂₁* p ' is with the interruption times C of first timer ₁₂Be adjusted into C ₁₂* u '; The count value C of more adjusted afterwards second timer ₂₁* whether p ' is less than the interruption times C of adjusted first timer ₁₂* u '; According to C ₂₁* p ' and C ₁₂* the level of second paths of LEDs is lighted or extinguished to the magnitude relationship correspondence of u ', thereby the duty ratio that changes the PWM ripple reaches the bright dark purpose of regulating second paths of LEDs; Output is once lighted or is extinguished after the level of second paths of LEDs, repeats to get into the light modulation step of first paths of LEDs, and so circulation is carried out, and can reach simultaneously the purpose that first paths of LEDs and second paths of LEDs are carried out light modulation; After the output of the second road PWM ripple, the bright dark controlled step of adding Third Road LED, the bright dark control method and second paths of LEDs of Third Road LED are similar ... So can realize the output of multi-channel PWM ripple, promptly realize the brightness adjustment control of LED multi-path;

Further, when the frequency that first timer interrupts is higher than the interruption frequency of first timer far away greater than the count frequency of the frequency of the second timer zero clearing and second timer at least, promptly adopt inverse and the said T of N ₃* the ratio of M is at least greater than 1 and T ₃Be far smaller than the inverse of said N, light-dimming method has grace time to carry out, so the LED light modulation can not shaken.

Description of drawings

Fig. 1 is the PWM light-dimming method schematic flow sheet of the LED of being used for provided by the invention;

Fig. 2 is the PWM light-dimming method schematic flow sheet that is used for LED that first embodiment of the invention provides;

Fig. 3 is N, the T of the PWM light-dimming method that is used for LED that provides of first embodiment of the invention ₁, M, p, u value relation list;

Fig. 4 is first timer and the second timer timing starting stage, PWM output waveform sketch map;

Fig. 5 is first timer and the second timer timing after after a while, PWM output waveform sketch map;

Fig. 6 is the first timer cumulative process sketch map in Fig. 2 method implementation;

Fig. 7 is the PWM light modulating device sketch map that is used for LED that first embodiment of the invention provides;

Fig. 8 (a)-(b) is the PWM light-dimming method schematic flow sheet that is used for LED that second embodiment of the invention provides;

Fig. 9 is the first timer cumulative process sketch map in Fig. 8 (a)-(b) method implementation.

Embodiment

The present invention uses the single-chip microcomputer with common input/output port just can realize the output of single channel PWM ripple, can realize the output of multi-channel PWM ripple again, promptly realizes the brightness adjustment control of single channel and LED multi-path.Concrete PWM light-dimming method, as shown in Figure 1, comprising:

Carry out S11, start the first timer that is in interrupt mode and the second timer that is in free count mode of single-chip microcomputer;

This step also can be described as first timer, the second timer of initialization single-chip microcomputer;

Carry out S12, statistics is in the interruption times of the said first timer of LED brightness changes phase and the count value of said second timer;

In said statistic processes, the count value of said second timer is carried out at least zero clearing;

Carry out S13, more said in real time interruption times and count value, the PWM ripple that the output level value changes with said comparative result; Wherein, said PWM ripple is used to be applied to LED to regulate its brightness.

For make above-mentioned purpose of the present invention, feature and advantage can be more obviously understandable, does detailed explanation below in conjunction with the accompanying drawing specific embodiments of the invention, owing to focus on explaining principle of the present invention, so do not draw to scale.

Embodiment one

Fig. 2 is the PWM light-dimming method schematic flow sheet that is used to control single LED that first embodiment of the invention provides.

In conjunction with Fig. 1 and Fig. 2, carry out S11, the first timer of initialization single-chip microcomputer, second timer;

Said first timer is set to interrupt mode, per second N time; Said second timer is set to free counting mode.

Then carry out S12; Statistics is in the interruption times of the said first timer of LED brightness changes phase and the count value of said second timer; Comprise: LED is in from secretly to the bright stage or from bright to dark the phase process; Add up the interruption times of said first timer, and zero clearing when counting first clear value, second timer begins freely to count and is every at a distance from very first time T ₃Counting increases by 1, zero clearing when the second timer counting arrives the first value M;

LED is from secretly to bright stage the time, and said first clear value is N*T ₁, during the stage, said first clear value is N*T from bright to dark ₂Said T ₁For LED from dark to bright required time, said T ₂For LED from bright to the dark required time; In method implementation shown in Figure 2, the first timer C ₁The method of accumulative total, as shown in Figure 6.

In the practical implementation process, the acquisition methods of said p and said u is: LED is from secretly to bright process, M*p=N*u*T ₁LED from bright to dark in the process, M*p=N*u*T ₂For example, N is set at 100, T ₁Be set at 1, that is: said first timer is set to every separated 1/100 second very first time interruption once, and LED is not 1 second from the complete bright required time that works, and the relation of then said first timer and said second timer becomes: M*p=100*u*1; If getting M is 200, then p/u=1/2 gets p=1, u=2, and like this, the value of p and u has just been decided.

Because light modulation in a certain set time, N is big more, and the stepping of light modulation is more little; Therefore, the size of N has determined the resolution of light modulation, causes the operand of single-chip microcomputer excessive but N obtains too conference; When operand surpasses the disposal ability of single-chip microcomputer, will inevitably cause the single-chip microcomputer computing to make mistakes, in addition; The N value is big more, and it is too frequent to mean that also first timer interrupts, and can cause the execution of each interruption faster than the S13 step; Cause the S13 step to have little time comparison, variation has just taken place in the interruption times of first timer.

The inventor finds that in actual use it is preferable interruption times that N gets 128.Fig. 3 has listed N and has got 128, different T ₁, p, u value that M is corresponding.

Because the least-significant byte that reads said second timer is more convenient, and institute takes time shortlyer, and therefore, general M gets 2 ⁸, promptly 256.Like this, the value of p and u has just been decided.

In the practical implementation process, said T ₃Be far smaller than the inverse of said N.For example said T ₃Can get 8 microseconds, promptly said second timer whenever increases by 1 at a distance from 8 microseconds, and the frequency that is equivalent to second timer is 125KHZ, and correspondingly, said first timer whenever interrupted once at a distance from 1/128 second, and the frequency of said first timer is 128HZ.

In the practical implementation process, the first timer of this step is from secretly falling into a trap to N*T to bright process ₁The time, also comprise the time T that the PWM ripple is exported second level is set ₆, make LED get into the complete bright stage, continue T ₆After time arrives, get into the process from bright to dark; So can be implemented in LED from secretly reaching complete when bright to bright process, make LED keep a period of time T in the complete bright stage ₆, said T ₆Can be provided with by the user.

Likewise, first timer is fallen into a trap to N*T in process from bright to dark ₂The time, also comprise the time T that the PWM ripple is exported first level is set ₇, make LED get into the complete dark stage, continue T ₇After time arrives, get into from dark to bright process; It is complete when dark that the process from bright to dark that so can be implemented in LED reaches, and makes LED keep a period of time T in the complete dark stage ₇, said T ₇Can be provided with by the user.

LED is not from secretly counting N*T to bright process ₁Shi Yucong is bright not to count N*T in dark process ₂The time, carry out S13, more said in real time interruption times and count value, the PWM ripple that the output level value changes with said comparative result; Wherein, said PWM ripple is used to be applied to LED to regulate its brightness, and this step comprises:

Count value C with second timer ₂Be adjusted into C ₂* p is with the interruption times C of first timer ₁Be adjusted into C ₁* u; Said p is second timer adjustment coefficient, and said u is first timer adjustment coefficient; This set-up procedure does not influence the count value C of second timer ₂Continue to continue increase step shown in Figure 6, also do not influence the interruption times C of first timer ₁Continue to add up;

The count value C of more adjusted second timer ₂* whether p is less than the interruption times C of adjusted first timer ₁* u; LED is current to be in from secretly to bright stage the time, if C ₂* p＜C ₁* u, then the PWM ripple is exported second level, otherwise exports first level; LED is current when being in from bright to dark the stage, if C ₂* p＜C ₁* u, then the PWM ripple is exported first level, otherwise exports second level; Said first level is the level that extinguishes LED, and said second level is a level of lighting LED.

In the general implementation process, said first level is a low level, and said second level is a high level, also can freely be set by the user.

Brief description is done to the light-dimming method in the method flow diagram of present embodiment shown in Figure 2 by following elder generation.

N gets 128 in the present embodiment one, and M gets 256, T ₁Got T 1 second ₂Got T 2 seconds ₃Get 8 microseconds, T ₆Got T 3 seconds ₇Got 4 seconds, with CH-PHASE=0 label L ED from secretly to the bright stage, complete bright stage of CH-PHASE=1 label L ED, CH-PHASE=2 label L ED stage from bright to dark, complete dark stage of CH-PHASE=3 label L ED.LED when beginning acquiescence is from secretly to bright stage, i.e. CH-PHASE=0.

From 1. beginning, carry out S121, judge earlier LED current whether be from from secretly to the bright stage, if not, carry out S210, judge LED current whether be to start from the complete bright stage;

If, carry out S122, then read the count value C of second timer ₂Interruption times C with first timer ₁, the interruption times C of first timer in this process ₁Accumulation method is as shown in Figure 6; At this moment, current LED is in from secretly to the bright stage.

Then carry out S123, judge the interruption times C of first timer ₁Whether equal N*T ₁, promptly whether first timer needs zero clearing at this moment; Do not count N*T ₁The time, carry out S131, with the count value C of second timer ₂Be adjusted into C ₂* p is with the interruption times C of first timer ₁Be adjusted into C ₁* u; Said p is second timer adjustment coefficient, and said u is first timer adjustment coefficient; Count N*T ₁The time, carry out S124 ', PWM ripple output 1.At this moment, C ₁Be 0, therefore do not count 128.

For describing conveniently, when setting high level, be in particular at 1 o'clock, LED lights; During low level, be in particular at 0 o'clock, LED extinguishes.Can certainly be according to the difference of LED, setting said first level is the level that extinguishes LED, said second level is a level of lighting LED;

Then, carry out S132, the value C of more adjusted second timer ₂* whether p is less than the interruption times C of adjusted first timer ₁* u;

Carry out S133, LED is current to be in from secretly to bright stage the time, if C ₂* p＜C ₁* u, then the output of PWM ripple 0, gets into and 1. locates, otherwise export 1, gets into and 1. locates;

Said step S131, S132, S133 belong to step S13, more said in real time interruption times and count value, the PWM ripple that the output level value changes with said comparative result.

Need to prove that after Fig. 6 executes and once withdraws from, 1. locate time 1/N during second apart from getting into last time, present embodiment one is 1/128 second, from 1. getting into, carries out program shown in Figure 6 once more automatically.

From 1. getting into, carry out S121-S122-S123-S131-S132-S133 repeatedly, in the time of 1 second, first timer at LED from the interruption times C to the bright process secretly ₁Count N*T ₁, 128, this moment, step S 123 conditions satisfied, and got into execution in step S124 ', output 1.Then carry out S125 ', the time T of PWM ripple output 1 is set ₆, the promptly complete bright time of staying.Then carry out S126 ', LED gets into the complete bright stage, and this moment, CH-PHASE was changed to 1, and program gets into and 1. locates.

From 1., at this moment, CH-PHASE=1, step S121 is judged as NO, gets into the S210 step, and step S210 is judged as YES, then carries out S211, output 1.Carry out S212, the complete bright time of staying of setting does not arrive, and gets into 1. to locate.After this, from Fig. 2 top 1., carry out S121-S210-S211-S212.Up to lasting T ₆After time arrived, when present embodiment one was 3 seconds, the result that step S212 judges was YES, carried out S213, and it is 2 that CH-PHASE is set, and LED gets into the process from bright to dark, gets into 1. to locate.

From 1., at this moment, CH-PHASE=2, step S121 is judged as NO, gets into the S210 step, and step S210 is judged as NO, gets into the S310 step, and step S310 is judged as YES.

Carry out S311, then read the count value C of second timer ₂Interruption times C with first timer ₁, the interruption times C of first timer in this process ₁Accumulation method is as shown in Figure 6;

Carry out S312, judge the interruption times C of first timer ₁Whether equal N*T ₂, promptly whether first timer needs zero clearing this moment, does not count N*T ₂The time, carry out S131, with the count value C of second timer ₂Be adjusted into C ₂* p is with the interruption times C of first timer ₁Be adjusted into C ₁* u; Said p is second timer adjustment coefficient, and said u is first timer adjustment coefficient.

Carry out S133, LED is current to be in from secretly to bright stage the time, if C ₂* p＜C ₁* u, then the output of PWM ripple 0, gets into and 1. locates, otherwise export 1, gets into and 1. locates.

From 1. getting into, carry out S121-S210-S310-S311-S312-S131-S132-S133 repeatedly, in the time of 6 seconds, first timer is at LED interruption times C in the process from bright to dark ₁Count N*T ₂, 256, this moment, step S312 condition satisfied, and got into execution in step S313 ', output 0.Then carry out S314 ', the time T of PWM ripple output 0 is set ₇, the promptly complete dark time of staying.Then carry out S315 ', LED gets into the complete dark stage, and this moment, CH-PHASE was changed to 3, and program gets into and 1. locates.

From 1., at this moment, CH-PHASE=3, step S121 is judged as NO, gets into the S210 step, and step S210 is judged as NO, gets into the S310 step, and step S310 is judged as NO, gets into 410 steps, and step S410 is judged as YES, then carries out S411, output 0.Carry out S412, the complete dark time of staying of setting does not arrive, and gets into and 1. locates.After this, from Fig. 2 top 1., carry out S121-S210-S310-S410-S411-S412.Up to lasting T ₇After time arrived, when present embodiment one was 10 seconds, the result that step S412 judges was YES, carried out S413, and it is 0 that CH-PHASE is set, and the LED entering, gets into and 1. locates to bright process from dark.

So far, LED accomplishes by dark to bright, 1 second consuming time, complete bright stop 3 seconds, by bright to dark, 2 seconds consuming time, secretly stop 4 seconds entirely.Above-mentioned this process afterwards circulates.

In the practical implementation process, also comprise the situation that a kind of LED makes mistakes, that is: the result that judges of S121-S210-S310-S410 be NO, and this situation user can be provided with reset routine, and present embodiment one is set to entering from secretly to bright stage, CH-PHASE=0.The user also can according to circumstances be set to other stage, for example complete bright stage, stage from bright to dark, complete dark stage.

Through above-mentioned S13 step, the PWM ripple has just changed duty ratio, and the PWM wave frequency after the said change duty ratio is the frequency of second timer zero clearing; It in the present embodiment one 8 microsecond *, 256 gained results' inverse; Being 488HZ, also is that the PWM wave frequency is the frequency of second timer counting and the ratio of the first value M, therefore; In order to export the PWM ripple of upper frequency, the frequency of second timer counting will be far longer than the clear value M of second timer.

Need to prove, after said first timer and said second timer pick up counting synchronously,, for example crossed 80 microseconds in the initial period, because said second timer is every at a distance from 8 microsecond increases once, so said C ₂Be 10 this moment, and said first timer is every to be increased once at a distance from 1/128 second, promptly 7.812 milliseconds, so C at this moment ₁Be 0, i.e. C ₂* p>=C ₁* u.The first timer C ₁For the first time count at 1 o'clock, spent 1/128 second, at this moment, the second timer C ₂Be 976 times, consider whenever once, i.e. C at a distance from 256 zero clearings ₂Be 208, to sum up, the first timer C ₁For the first time count at 1 o'clock, C ₂* p>=C ₁* u is in from secretly to the bright stage if LED is current, then in the starting stage, and said input/output port output 0, the duty ratio of PWM ripple is 0.

Along with the increase of said first timer counting, for example by 60 o'clock, this moment C ₁* u=120, C ₂* p is (256-120)/256=53.125% more than or equal to 120 probability; Be in from secretly to the bright stage if LED is current, the probability of said input/output port output 0 is 53.125%, and the probability of output 1 is 46.875%; The duty ratio of PWM ripple is 46.875%, and is as shown in Figure 4.Because shorter to the time of bright starting stage output 1, so that LED seems is dark from secretly.

When said first timer counting is increased to 127, this moment C ₁* u=254, C ₂* p is (256-254)/256=0.78% more than or equal to 254 probability, is in the gradually bright stage if LED is current, and the probability of said input/output port output 0 is 0.78%, and the probability of output 1 is 99.22%, and the duty ratio of PWM ripple is 99.22%, and is as shown in Figure 5.Because longer to the time of bright end stage output 1, so that LED seems is bright from secretly.

Inventor of the present invention finds in actual production, the inverse of said N and said T ₃* greater than 1 and the count frequency of second timer when being higher than the interruption frequency of first timer far away, said step S12-S13 has grace time to carry out and the LED light modulation can not shaken at least for the ratio of M.

The present invention also provides a kind of device 1 that is used to realize the PWM light-dimming method of LED, and is as shown in Figure 7, comprising:

Single-chip microcomputer 11, said single-chip microcomputer 11 comprises: first timer 111, second timer 112, first zero clearing are provided with device 113; Said first timer 111 is used for per second to interrupt N time, and LED is in from secretly the phase process, adding up the interruption times of said first timer to the bright stage or from bright to dark, and zero clearing when counting first clear value; Second timer 112 is used for freely counting, and LED is in from secretly to the bright stage or from bright to dark the phase process, and is every at a distance from very first time T ₃Counting increases by 1, zero clearing when counting arrives the first value M; Said first zero clearing is provided with device 113 and is applicable at LED from secretly to bright process, being set to N*T ₁, from bright to dark, be set to N*T in the process ₂, said T ₁For LED from dark to bright required time, said T ₂For LED from bright to the dark required time;

Pwm signal generator 12 comprises: the current phase acquisition device 121 of living in of LED and first comparator 122; Said first comparator 122 is applicable to that with first timer 111, second timer 112, the first zero clearings device 113 being set links to each other, and is used for the value C of more adjusted second timer 112 ₂* whether p is less than the interruption times C of adjusted first timer 111 ₁* u; Said C ₂Be the count value of second timer 112, said C ₁Be the interruption times of first timer 111, said p is second timer, 112 adjustment coefficients, and said u is first timer, 111 adjustment coefficients;

When the result of said first comparator 122 for being, and the current phase acquisition device 121 of living in of LED obtains the result for from secretly when bright, pwm signal generator 12 outputs second level, otherwise export first level; When the result of said first comparator 122 for being, and the current phase acquisition device 121 of living in of LED obtains the result for from bright to dark the time, pwm signal generator 12 outputs first level, otherwise export second level; Said first level is the level that extinguishes LED, and said second level is a level of lighting LED.

In the practical implementation process, light modulating device 1 also comprises:

First collector 13 is connected with pwm signal generator 12 with first timer 111, is applicable to gather the time that the PWM ripple is exported second level, and said first timer 111 is from secretly falling into a trap to N*T to bright process ₁The time, LED gets into the complete bright stage, after the time of output second level of lasting said setting arrives, gets into the process from bright to dark;

Second collector 14 is connected with pwm signal generator 12 with first timer 111, is applicable to gather the time that the PWM ripple is exported first level, and said first timer 111 is fallen into a trap to N*T in process from bright to dark ₂The time, LED gets into the complete dark stage, after the time of output first level of lasting said setting arrives, gets into from dark to bright process;

P and u getter 15 link to each other with said first comparator 122, are applicable to that LED is from secretly to bright process, according to M*p=N*u*T ₁Obtain; LED is from bright to dark in the process, according to M*p=N*u*T ₂Obtain.

In addition, single-chip microcomputer 11 can also comprise: input/output port 114, said input/output port 114 are used for the PWM ripple that output pwm signal generator 12 produces.

Embodiment two

Control the PWM light modulation of two paths of LED if desired, the time of the bright dark mode of two paths of LED and needs is all identical, then PWM is applied to last the getting final product of LED of two-way.

If the bright dark mode of two paths of LED or the asynchronism(-nization) that needs, the light-dimming method and the device that then can adopt present embodiment two to provide.

Among Fig. 8 (a), with CH1-PHASE=0 mark first paths of LEDs from secretly to the bright stage, complete bright stage of CH1-PHASE=1 mark first paths of LEDs, CH1-PHASE=2 mark first paths of LEDs stage from bright to dark, complete dark stage of CH1-PHASE=3 mark first paths of LEDs.First paths of LEDs when beginning acquiescence is from secretly to bright stage, i.e. CH1-PHASE=0.

Among Fig. 8 (b), with CH2-PHASE=0 mark second paths of LEDs from secretly to the bright stage, complete bright stage of CH1-PHASE=2 mark second paths of LEDs, CH2-PHASE=2 mark second paths of LEDs stage from bright to dark, complete dark stage of CH2-PHASE=3 mark second paths of LEDs.Second paths of LEDs when beginning acquiescence is from secretly to bright stage, i.e. CH2-PHASE=0.

The bright dark mode of first paths of LEDs is identical with the single LED of time that needs and embodiment one, and two kinds of N of present embodiment get 128, and M gets 256, T ₁Got T 1 second ₂Got T 2 seconds ₃Get 8 microseconds, T ₆Got T 3 seconds ₇Got T 4 seconds ₄Got T 3 seconds ₅Got T 4 seconds ₉Got T 2 seconds ₁₀Got 1.5 seconds.

Accordingly, the light-dimming method of the single LED that the light-dimming method of first paths of LEDs in the present embodiment two and embodiment one provide is basic identical, and different places are; In the S11 step, after the first timer of initialization single-chip microcomputer, the second timer step, from 1. getting into; The light-dimming method of first paths of LEDs also comprises: step S120, judge whether the first paths of LEDs output enable is opened, if breakdown not; Execution in step S121 '; Then extinguish first paths of LEDs, first paths of LEDs gets into the complete dark stage, gets into and 3. locates;

If open; Then add up in the interruption times of the said first timer of LED brightness changes phase and the count value of said second timer; Comprise: first paths of LEDs be in from secretly to the bright stage or from bright to dark the stage, first timer gets into the statistics interruption times, second timer begins freely to count.

PWM light-dimming method flow process below in conjunction with Fig. 8 (a)-(b) controls two paths of LED to second embodiment of the invention being used to of providing is carried out brief description.

From 1. getting into, execution in step S120 judges whether the first paths of LEDs output enable is opened, if breakdown not, execution in step S121 ' then extinguishes first paths of LEDs, and first paths of LEDs gets into the complete dark stage, gets into and 3. locates;

If open, execution in step S121, judge earlier first paths of LEDs current whether be from from secretly to the bright stage, if not, carry out S210, judge first paths of LEDs current whether be to start from the complete bright stage.

If, carry out S122, then read the count value C of second timer ₂Interruption times C with first timer ₁At this moment, current first paths of LEDs was in from secretly to the bright stage, the interruption times C of first timer in this process ₁Accumulation method is as shown in Figure 9.

For describing conveniently, when setting high level, be in particular at 1 o'clock, first paths of LEDs is lighted; During low level, be in particular at 0 o'clock, first paths of LEDs extinguishes.Can certainly be according to the difference of first paths of LEDs, setting said first level is the level that extinguishes first paths of LEDs, said second level is a level of lighting first paths of LEDs;

Carry out S133, LED is current to be in from secretly to bright stage the time, if C ₂* p＜C ₁* u, then the output of PWM ripple 1, gets into and 3. locates, otherwise export 0, gets into and 3. locates;

Said step S131, S132, S133 belong to step S13, change the duty ratio of PWM ripple and regulate the bright dark of first paths of LEDs.

From 3. getting into, execution in step S1120 judges whether the second paths of LEDs output enable is opened, if breakdown not, execution in step S1121 ' then extinguishes second paths of LEDs, and second paths of LEDs gets into the complete dark stage, gets into and 1. locates;

If open, execution in step S1121, judge earlier second paths of LEDs current whether be to be in from secretly to the bright stage, if not, carry out S1210, judge second paths of LEDs current whether be to start from the complete bright stage.

If, carry out S1122, then read the count value C of second timer ₂₁Interruption times C with first timer ₁₂, the interruption times C of first timer in this process ₁₂Accumulation method is as shown in Figure 9; At this moment, current second paths of LEDs is in from secretly to the bright stage.

Then carry out S1123, judge the interruption times C of first timer ₁₂Whether equal N*T ₄, promptly whether first timer needs zero clearing at this moment; Do not count N*T ₄The time, carry out S1131, with the count value C of second timer ₂₁Be adjusted into C ₂₁* p ' is with the interruption times C of first timer ₁₂Be adjusted into C ₁₂* u '; Said p ' is second timer adjustment coefficient, and said u ' is first timer adjustment coefficient; Count N*T ₄The time, carry out S1124 ', PWM ripple output 1.At this moment, C ₁₂Be 0, therefore do not count 384.

For describing conveniently, when setting high level, be in particular at 1 o'clock, second paths of LEDs is lighted; During low level, be in particular at 0 o'clock, second paths of LEDs extinguishes.Can certainly be according to the difference of second paths of LEDs, setting said first level is the level that extinguishes second paths of LEDs, said second level is a level of lighting second paths of LEDs;

Then, carry out S1132, the value C of more adjusted second timer ₂₁* whether p ' is less than the interruption times C of adjusted first timer ₁₂* u ';

Carry out S1133, LED is current to be in from secretly to bright stage the time, if C ₂₁* p '＜C ₁₂* u ', then the output of PWM ripple 1, gets into and 1. locates, otherwise export 0, gets into and 1. locates;

Said step S1131, S1132, S1133 belong to step S113, more said in real time interruption times and count value, the PWM ripple that the output level value changes with said comparative result.

Need to prove, after Fig. 9 executes and once withdraws from, 1. locate time 1/N during second apart from getting into last time, is 1/128 second in the present embodiment two, from 1. getting into, carries out program shown in Figure 9 once more automatically.

From 1. getting into, carry out S120-S121-S122-S123-S131-S132-S133-S1120-S1121-S1122-S11 23-S1131-S1132-S1133 repeatedly, in the time of 1 second, first timer at first paths of LEDs from the interruption times C to the bright process secretly ₁Count N*T ₁, 128, this moment, step S123 condition satisfied, and got into execution in step S124 ', output 1.Then carry out S125 ', the time T of PWM ripple output 1 is set ₆, i.e. complete bright time of staying of first paths of LEDs.Then carry out S126 ', first paths of LEDs gets into the complete bright stage, and this moment, CH1-PHASE was changed to 1, and program gets into and 3. locates.

From 3. entering, execution in step S1120-S1121-S1122-S1123-S1131-S1132-S1133, program gets into and 1. locates.

From 1., at this moment, CH1-PHASE=1, step S121 is judged as NO, gets into the S210 step, and step S210 is judged as YES, then carries out S211, output 1.Carry out S212, the complete bright time of staying of setting does not arrive, and gets into 3. to locate.From 3. getting into, then execution in step S1120-S1121-S1122-S1123-S1131-S1132-S1133 gets into and 1. locates.

After this, from Fig. 8 (a) top 1., carry out S120-S121-S210-S211-S212-S1120-S1121-S1122-S1123-S1131-S 1132-S1133 repeatedly, get into and 1. locate.When amounting to 3 seconds up to picking up counting, first timer at second paths of LEDs from the interruption times C to the bright process secretly ₁₂Count N*T ₄, 384, this moment, step S1123 condition satisfied, and got into execution in step S1124 ', output 1.Then carry out S1125 ', the time T of PWM ripple output 1 is set ₉, i.e. complete bright time of staying of second paths of LEDs.Then carry out S1126 ', second paths of LEDs gets into the complete bright stage, and this moment, CH2-PHASE was changed to 1, and program gets into and 1. locates.

From 1. getting into, carry out S120-S121-S210-S211-S212-S1120, at this moment, and CH2-PHASE=1, step S1121 is judged as NO, gets into the S1210 step, and step S1210 is judged as YES, then carries out S1211, output 1.Carry out S1212, the complete bright time of staying of setting does not arrive, and gets into 1. to locate.From 1. getting into, then execution in step S120-S121-S210-S211-S212-S1120-S1121-S1210-S1211-S1212 gets into and 1. locates.

After this, from Fig. 8 (a) top 1., carry out S120-S121-S210-S211-S212-S1120-S1121-S1210-S1211-S1212 repeatedly, get into and 1. locate.Up to lasting T ₆After time arrived, when present embodiment two beginning backs amounted to 4 seconds, the result that step S212 judges was YES, carries out S213, and it is that 2, the first paths of LEDs get into the process from bright to dark that CH1-PHASE is set, and gets into 3. to locate.

From 3. getting into, then execution in step S1120-S1121-S1210-S1211-S1212 gets into and 1. locates.

From 1. getting into, at this moment, CH1-PHASE=2, step S121 is judged as NO, gets into the S210 step, and step S210 is judged as NO, gets into the S310 step, and step S310 is judged as YES.Then carry out S311, then read the count value C of second timer ₂Interruption times C with first timer ₁The interruption times C of first timer in this process ₁Accumulation method is as shown in Figure 9.

Carry out S133, LED is current when being in from bright to dark the stage, if C ₂* p＜C ₁* u, then the output of PWM ripple 0, gets into and 3. locates, otherwise export 1, gets into and 3. locates.

From 3. getting into, carry out S1120-S1121-S1210-S1211-S1212.

After this, repeat S120-S121-S210-S310-S311-S312-S131-S132-S133-S1120-S1121-S1210-S1211-S1212, up to lasting T ₉After time arrived, present embodiment two was when beginning to amount to 5 seconds, and the result that step S1212 judges be YES, carries out S1213, and it is that 2, the second paths of LEDs get into the process from bright to dark that CH2-PHASE is set, and 1. entering is located.

From 1. getting into, carry out S120-S121-S210-S310-S311-S312-S131-S132-S133-S1120, at this moment; CH2-PHASE=2, step S1121 is judged as NO, gets into the S1210 step; Step S1210 is judged as NO, gets into the S1310 step, and step S1310 is judged as YES.

Then carry out S1311, then read the count value C of second timer ₂₁Interruption times C with first timer ₁₂The interruption times C of first timer in this process ₁₂Accumulation method is as shown in Figure 9

Then carry out S1312, judge the interruption times C of first timer ₁₂Whether equal N*T ₅, promptly whether first timer needs zero clearing at this moment; Do not count N*T ₅The time, carry out S1131, with the count value C of second timer ₂₁Be adjusted into C ₂₁* p ' is with the interruption times C of first timer ₁₂Be adjusted into C ₁₂* u '; Said p ' is second timer adjustment coefficient, and said u ' is first timer adjustment coefficient; Count N*T ₅The time, carry out S1313 ', PWM ripple output 0.At this moment, C ₁₂Be 0, therefore do not count 512.

Carry out S1133, LED is current when being in from bright to dark the stage, if C ₂₁* p '＜C ₁₂* u ', then the output of PWM ripple 0, gets into and 1. locates, otherwise export 1, gets into and 1. locates.

From 1. getting into, then execution in step S120-S121-S210-S310-S311-S312-S131-S132-133-S1120-S1121-S1210-S1310-S1311-S1312-S1131-S1132-1133 gets into and 1. locates.

After this, execution in step S120-S121-S210-S310-S311-S312-S131-S132-133-S1120-S1121-S1210-S1310-S1311-S1312-S1131-S1132-1133 repeatedly.Up to picking up counting 6 seconds the time, first timer at second paths of LEDs from the interruption times C to the bright process secretly ₁Count N*T ₂, 256, this moment, step S312 condition satisfied, and got into execution in step S313 ', output 0.Then carry out S314 ', the time T of PWM ripple output 0 is set ₇, the promptly complete dark time of staying.Then carry out S315 ', first paths of LEDs gets into the complete dark stage, and this moment, CH1-PHASE was changed to 3, and program gets into and 3. locates.

From 3. getting into, carry out S1120-S1121-S1210-S1310-S1311-S1312-S1131-S1132-S1133, get into and 1. locate.

From 1. getting into, at this moment, CH1-PHASE=3, step S121 is judged as NO, gets into the S210 step, and step S210 is judged as NO, gets into the S310 step, and step S310 is judged as NO, gets into the S410 step, and step S410 is judged as YES, then carries out S411, output 0.Carry out S412, the complete dark time of staying of setting does not arrive, and gets into and 3. locates.From 3. getting into, then execution in step S1120-S1121-S1210-S1310-S1311-S1312-S1131-S1132-S1133 gets into and 1. locates.

After this, from Fig. 8 (a) top 1., execution in step S120-S121-S210-S310-S410-S411-S412-S1120-S1121-S1210-S13 10-S1311-S1312-S1131-S1132-1133 gets into and 1. locates repeatedly.Up to picking up counting 9 seconds the time, first timer at second paths of LEDs from the interruption times C to the bright process secretly ₁₂Count N*T ₅, 512, this moment, step S1312 condition satisfied, and got into execution in step S1313 ', output 0.Then carry out S1314 ', the time T of PWM ripple output 0 is set ₁₀, the promptly complete dark time of staying.Then carry out S1315 ', second paths of LEDs gets into the complete dark stage, and this moment, CH2-PHASE was changed to 3, and program gets into and 1. locates.

From 1. entering, execution in step S120-S121-S210-S310-S410-S411-S412-S1120, at this moment; Step S1121 is judged as NO, gets into the S1210 step, and step S1210 is judged as NO; Get into the S1310 step, step S1310 is judged as NO, gets into the S1410 step; Step S1410 is judged as YES, then carries out S1411, output 0.Carry out S1412, the complete dark time of staying of setting does not arrive, and gets into and 1. locates.From 1. getting into, execution in step S120-S121-S210-S310-S410-S411-S412-S1120-S1121-S1210-S13 10-S1410-S1411-S1412 gets into and 1. locates.

After this, from Fig. 8 (a) top 1., execution in step S120-S121-S210-S310-S410-S411-S412-S1120-S1121-S1210-S13 10-S1410-S1411-S1412 gets into and 1. locates repeatedly.Up to lasting T ₅After time arrived, when present embodiment two beginning back amounted to 10 seconds, the result that step S412 judges be YES, carries out S413, CH1-PHASE is set is 0, the first paths of LEDs and get into from dark to bright process, and 3. entering is located.

From 3. entering, execution in step S1120-S1121-S1210-S1310-S1410-S1411-S1412 gets into and 1. locates.

From 1. entering, execution in step S120, this moment, CH1-PHASE was 0, and step S121 is judged as YES, and then execution in step S122-S123-S131-S132-S133-S1120-S1121-S1210-S1310-S1410-S 1411-S1412 gets into and 1. locates.

After this, from Fig. 8 (a) top 1., execution in step S120-S121-S122-S123-S131-S132-S133-S1120-S1121-S1210-S13 10-S1410-S1411-S1412 gets into and 1. locates repeatedly.Up to lasting T ₁₀After time arrived, when present embodiment two beginning back amounted to 10.5 seconds, the result that step S1412 judges be YES, carries out S1413, CH2-PHASE is set is 0, the second paths of LEDs and get into from dark to bright process, and 1. entering is located.

So far, the first via and second paths of LEDs are accomplished respectively once from secretly to bright, stay for some time at Liang Chu, the promptly complete bright time, in the dark stay for some time to secretly from bright, i.e. the step of complete dark time.

After this, 1. first paths of LEDs and the circulation of second paths of LEDs get into from the top of Fig. 8 (a), 1. come out from the below of Fig. 8 (b), 1. get into from the top from Fig. 8 (a) again ..., so circulation can realize continuous light tuning.

For second paths of LEDs, the acquisition methods of said p ' and said u ' is: second paths of LEDs is from secretly to bright process, M ' * p '=N*u ' * T ₄Second paths of LEDs from bright to dark in the process, M ' * p '=N*u ' * T ₅

In the practical implementation process; Identical with embodiment one, also comprise the situation that a kind of LED makes mistakes, that is: the result of S121-S210-S310-S410 judgement is NO; This situation user can be provided with reset routine; Present embodiment two is set to first paths of LEDs and gets into from secretly to the bright stage, and CH1-PHASE=0 gets into the second paths of LEDs light modulation step afterwards.Or the result that S1121-S1210-S1310-S1410 judges be NO, and this situation user also can be provided with reset routine, and present embodiment two is set to the entering of second paths of LEDs from secretly to bright stage, CH2-PHASE=0.The user also can according to circumstances be set to other stage, for example complete bright stage, stage from bright to dark, complete dark stage.

Present embodiment two also can be provided with and let first paths of LEDs or second paths of LEDs temporarily stop to enable.

Need to prove that the asynchronism(-nization) of different bright dark modes of multichannel or needs if desired can 3. locating below second embodiment Fig. 8 (a) increase.

Correspondingly, the device that the PWM light-dimming method of the two paths of LED that second embodiment provides is corresponding on the basis of device 1, also comprises:

First determining device links to each other with said pwm signal generator, is used to judge whether the first paths of LEDs output enable is opened;

Second determining device links to each other with said pwm signal generator, is used to judge whether the second paths of LEDs output enable is opened;

Second zero clearing is provided with device, is used at second paths of LEDs from secretly being set to N*T to bright process ₄, from bright to dark, be set to N*T in the process ₅, said T ₄Be second paths of LEDs from dark to bright required time, said T ₅Be second paths of LEDs from bright to the dark required time;

P ' and u ' getter, be used for second paths of LEDs from secretly to bright process, according to M ' * p '=N*u ' * T ₄Obtain; From bright to dark in the process, according to M ' * p '=N*u ' * T ₅Obtain;

Said first collector 13 also is applicable to be gathered the time that the second road PWM ripple is exported second level, and said first timer 111 is from secretly falling into a trap to N*T to bright process ₄The time, second paths of LEDs gets into the complete bright stage, after the time of output second level of lasting said setting arrives, gets into the process from bright to dark;

Said second collector 14 also is applicable to be gathered the time that the second road PWM ripple is exported first level, and said first timer 111 is fallen into a trap to N*T in process from bright to dark ₅The time, second paths of LEDs gets into the complete dark stage, after the time of output first level of lasting said setting arrives, gets into from dark to bright process;

Said pwm signal generator also comprises second comparator; Said second comparator is applicable to that with u ' getter, second zero clearing device being set with said first timer, second timer, p ' links to each other, and is used for the value C of more adjusted second timer ₂₁* whether p ' is less than the interruption times C of adjusted first timer ₁₂* u '; Said C ₂₁Be second paths of LEDs be in from secretly to bright or from bright to dark the count value of second timer the process, said C ₁₂For be second paths of LEDs be in from secretly to bright or from bright to dark the interruption times of first timer the process, said p ' is second timer adjustment coefficient, said u ' is first timer adjustment coefficient;

When the result of said second comparator for being, and the current phase acquisition device of living in of LED obtains the second paths of LEDs result for from secretly when bright, the pwm signal generator is exported second level, otherwise exports first level; When the result of said second comparator for not, and the current phase acquisition device of living in of LED obtains the second paths of LEDs result for from bright to dark the time, the pwm signal generator is exported first level, otherwise exports second level; Said first level is the level that extinguishes second paths of LEDs, and said second level is a level of lighting second paths of LEDs.

Though the present invention with preferred embodiment openly as above; But it is not to be used for limiting the present invention; Any those skilled in the art are not breaking away from the spirit and scope of the present invention; Can utilize the method and the technology contents of above-mentioned announcement that technical scheme of the present invention is made possible change and modification, therefore, every content that does not break away from technical scheme of the present invention; To any simple modification, equivalent variations and modification that above embodiment did, all belong to the protection range of technical scheme of the present invention according to technical spirit of the present invention.

Claims

1. a PWM light-dimming method that is used for LED is characterized in that,

2. the PWM light-dimming method that is used for LED according to claim 1 is characterized in that, said first timer is set to per second and interrupts N time; Said second timer is every at a distance from very first time T ₃Counting increases by 1, zero clearing when the second timer counting arrives the first value M, the inverse of said N and said T ₃* the ratio of M is at least greater than 1.

3. the PWM light-dimming method that is used for LED according to claim 1 is characterized in that, also comprises:

4. the PWM light-dimming method that is used for LED according to claim 2; It is characterized in that; In the count value process of the interruption times of the said first timer of said statistics and said second timer, the interruption times of the said first timer of statistics is carried out a zero clearing.

5. the PWM light-dimming method that is used for LED according to claim 4 is characterized in that, LED is from secretly to bright stage the time, and the first timer interruption times counts on N*T ₁The time zero clearing, during the stage, the first timer interruption times counts on N*T from bright to dark ₂The time zero clearing; Said T ₁For LED from dark to bright required time, said T ₂For LED from bright to the dark required time.

6. the PWM light-dimming method that is used for LED according to claim 5 is characterized in that, also comprises: said first timer is from secretly counting down to N*T to bright process ₁The time, the time that the PWM ripple is exported second level is set, LED gets into the complete bright stage, after the time of output second level of lasting said setting arrives, gets into the process from bright to dark; Do not count N*T ₁The time, carry out said real-time more said interruption times and count value, the PWM ripple step that the output level value changes with said comparative result.

7. according to claim 5 or the 6 described PWM light-dimming methods that are used for LED, it is characterized in that also comprise: said first timer is fallen into a trap to N*T in process from bright to dark ₂The time, the time that the PWM ripple is exported first level is set, LED gets into the complete dark stage, after the time of output first level of lasting said setting arrives, gets into from dark to bright process; Do not count N*T ₂The time, carry out said real-time more said interruption times and count value, the PWM ripple step that the output level value changes with said comparative result.

8. the PWM light-dimming method that is used for LED according to claim 3 is characterized in that the acquisition methods of said p and said u is: LED is from secretly to bright process, M*p=N*u*T ₁LED from bright to dark in the process, M*p=N*u*T ₂

9. the PWM light-dimming method that is used for LED according to claim 2 is characterized in that said T ₃Be far smaller than the inverse of said N.

10. the PWM light-dimming method that is used for LED according to claim 2 is characterized in that said T ₃Inverse be far longer than the first value M.

11. the PWM light-dimming method that is used for LED according to claim 3 is characterized in that said first level is a low level, said second level is a high level.

12. a PWM light-dimming method that is used for LED is characterized in that said LED is a two-way, said light-dimming method comprises: the first timer that is in interrupt mode and the second timer that is in free count mode that start single-chip microcomputer;

13. the PWM light-dimming method that is used for LED according to claim 12 is characterized in that, gets into the PWM light-dimming method of first via LED after the PWM light-dimming method output level value of said second paths of LEDs.

14. the PWM light-dimming method that is used for LED according to claim 12 is characterized in that, the PWM light-dimming method of said first paths of LEDs also comprises:

The PWM light-dimming method of said second paths of LEDs also comprises:

15. the PWM light-dimming method that is used for LED according to claim 12; It is characterized in that statistics also comprises in the interruption times of the said first timer of the second paths of LEDs brightness changes phase and the count value step of said second timer: the interruption times of said first timer to statistics is carried out a zero clearing.

16. the PWM light-dimming method that is used for LED according to claim 15 is characterized in that, from secretly to bright stage the time, the first timer interruption times counts on N*T at second paths of LEDs ₄The time zero clearing, during the stage, the first timer interruption times counts on N*T from bright to dark ₅The time zero clearing; Said T ₄Be second paths of LEDs from dark to bright required time, said T ₅Be second paths of LEDs from bright to the dark required time.

17. the PWM light-dimming method that is used for LED according to claim 14 is characterized in that, the acquisition methods of said p ' and said u ' is: second paths of LEDs is from secretly to bright process, M*p '=N*u ' * T ₄Second paths of LEDs from bright to dark in the process, M*p '=N*u ' * T ₅

18. the PWM light-dimming method that is used for LED according to claim 16 is characterized in that, also comprises: said first timer is from secretly falling into a trap to N*T to bright process ₄The time, the time that the PWM ripple is exported second level is set, second paths of LEDs gets into the complete bright stage, after the time of output second level of lasting said setting arrives, gets into the process from bright to dark; Do not count N*T ₄The time, carry out the interruption times and the count value of the said second paths of LEDs brightness changes phase, the output level value forms the second road PWM ripple step that changes with said comparative result.

19., it is characterized in that also comprise: said first timer is fallen into a trap to N*T in process from bright to dark according to claim 16 or the 18 described PWM light-dimming methods that are used for LED ₅The time, the time that the PWM ripple is exported first level is set, second paths of LEDs gets into the complete dark stage, after the time of output first level of lasting said setting arrives, gets into from dark to bright process; Do not count N*T ₅The time, carry out the interruption times and the count value of the said second paths of LEDs brightness changes phase, the output level value forms the second road PWM ripple step that changes with said comparative result.

20. the PWM light-dimming method that is used for LED according to claim 12; It is characterized in that; Also comprise Third Road LED; Export the PWM light-dimming method that gets into Third Road LED behind the level value of second paths of LEDs, statistics is in the interruption times of the said first timer of Third Road LED brightness changes phase and the count value of said second timer; In said statistic processes, the count value of said second timer is carried out at least zero clearing;

21. a PWM light modulating device that is used for LED is characterized in that, comprising:

22. light modulating device according to claim 21; It is characterized in that, also comprise: first collector is connected with the pwm signal generator with first timer; Be used to gather the time that the PWM ripple is exported second level, said first timer is from secretly falling into a trap to N*T to bright process ₁The time, LED gets into the complete bright stage, after the time of output second level of lasting said setting arrives, gets into the process from bright to dark.

23. according to claim 21 or 22 described light modulating devices; It is characterized in that, also comprise: second collector is connected with the pwm signal generator with first timer; Be used to gather the time that the PWM ripple is exported first level, said first timer is fallen into a trap to N*T in process from bright to dark ₂The time, LED gets into the complete dark stage, after the time of output first level of lasting said setting arrives, gets into from dark to bright process.

24. light modulating device according to claim 21 is characterized in that, also comprises: p and u getter, link to each other with said first comparator, be used for LED from secretly to bright process, according to M*p=N*u*T ₁Obtain p, u value; From bright to dark in the process, according to M*p=N*u*T ₂Obtain p, u value.