CN102595732A - LED (light-emitting diode) temperature control method and system based on PWM (pulse width modulation) - Google Patents
LED (light-emitting diode) temperature control method and system based on PWM (pulse width modulation) Download PDFInfo
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- CN102595732A CN102595732A CN2012100453229A CN201210045322A CN102595732A CN 102595732 A CN102595732 A CN 102595732A CN 2012100453229 A CN2012100453229 A CN 2012100453229A CN 201210045322 A CN201210045322 A CN 201210045322A CN 102595732 A CN102595732 A CN 102595732A
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Abstract
The invention discloses an LED (light-emitting diode) temperature control method and system based on PWM (pulse width modulation). The method comprises the following steps: detecting voltage U1 of a photoresistor through a controller and figuring out the brightness of an LED; calculating the current total power consumption W1 of the LED according to PWM duty ratio d1, performing power consumption table lookup according to the W1, finding out the light efficiency eta 1 which needs to be achieved by the LED at the current W1, calculating the current light efficiency eta 2 according to the brightness of the LED and the current total power consumption W1, comparing the eta 1 with the eta 2, screening out points with the total power consumption W2 which is lower than W1 according to a temperature-light efficiency curve if the eta 2 is less than the eta 1, calculating PWM duty ratio d2 according to the total power consumption W2 and adjusting a PWM output signal according to the d2 so as to always control the temperature of a circuit of the LED in an appropriate range, prevent the temperature from being too high and affecting the light efficiency of the LED. According to the method disclosed by the invention, the LED can work in the appropriate temperature range, fully play the light efficiency and realize the optimal balance among the brightness of the LED, the light efficiency and the temperature. The LED temperature control system disclosed by the invention is simple in structure and low in cost.
Description
Technical field
The present invention relates to a kind of temperature control technology field of LED lighting apparatus, be specifically related to a kind of LED temperature-controlled process and system based on PWM.
Background technology
Advantages such as LED is long because of the life-span, efficient is high, energy-conservation, the application in lighting field more and more widely.But the life-span of LED and optical efficiency and working temperature have substantial connection, and after temperature surpassed certain value, its optical efficiency and life-span can descend rapidly.Because the decline of optical efficiency, the brightness of LED descends, and more power consumption can change into heat energy and dissipate; If the LED of adjustable brightness increases electric current this moment in order to increase brightness, can further increase its caloric value, not only do not have the purpose that increases brightness, can quicken the aging of LED on the contrary.
At present, the control temperature methods in the led circuit generally is to dispel the heat through increasing radiator; Reduce the working temperature of LED passively; Because problems such as process Installation guarantee that to the LED of different batches is very difficult the effect of its heat radiation is identical, in the same even LED lighting apparatus; Since each LED factors such as position, its radiating effect is also not necessarily identical; Perhaps change caloric value, and this mode is difficult to the person's of being used acceptance through regulating LED brightness.
At " a kind of power method and system that improves the LED lamp " (application number 201010154632.5; Open day on September 22nd, 2010; Publication number CN101841956A) proposed in the patent document to combine through radiator and temperature detection and control; Guaranteeing that the LED temperature not under the situation of the ultra upper limit, strengthens immediate current as far as possible, thereby improves the power of LED as far as possible.This kind method and apparatus also exists temperature to be difficult to the problem of accurately measuring and controlling.Simultaneously, the formation of the hardware device that this method needs is also complicated, and cost is corresponding higher.
Summary of the invention
In order to solve the deficiency in the above-mentioned technology, the present invention provides a kind of and can make LED in suitable temperature range, work, give full play to its optical efficiency and can realize that LED brightness and optical efficiency, temperature reach the LED temperature-controlled process and the system based on PWM of optimum balance.
In order to reach the foregoing invention purpose, the technical scheme that the present invention adopts is: a kind of LED temperature-controlled process based on PWM is provided, it is characterized in that, may further comprise the steps:
A, brightness detect the voltage U 1 of loop detection photo resistance or light-sensitive semiconductor element and voltage U 1 are outputed to AD converter and outputs to controller by AD converter again, are calculated the brightness of LED then according to voltage U 1 by controller; Perhaps directly voltage U 1 is outputed to the controller that is built-in with AD converter, calculate the brightness of LED again by controller according to voltage U 1;
B, controller calculate the current total power consumption W1 of LED according to PWM duty ratio d1 in the current control circuit, and controller carries out power consumption with current total power consumption W1 tables look-up, and find out the optical efficiency η 1 that LED should reach when current total power consumption W1;
The brightness of the LED that c, controller calculate according to step a and the current total power consumption W1 of the LED that step b calculates calculate the optical efficiency η 2 of LED in the current system;
D, comparison η 1 and η 2; If η 2＜η 1; Then controller is inquired about according to the temperature-luminous efficiency curve tables of data in 2 pairs of controllers of η, and a sets of curves that finds optical efficiency to equate with η 2 filters out the total power consumption point lower than current total power consumption W1 simultaneously in this sets of curves; If η 2=η 1, then controller is not done any adjustment, and time-delay a period of time is detected again;
If e finds the point described in the steps d, controller calculates PWM duty ratio d2 according to the total power consumption W2 of this point, and according to the PWM output signal of duty ratio d2 adjustment control LED, and PWM is exported signal outputs to drive circuit; If do not find the point described in the steps d, then controller is not done any adjustment, and time-delay a period of time is detected again.
Said temperature-luminous efficiency curve is a sets of curves relevant with the LED self character, comprises parameter optical efficiency, total power consumption, temperature, voltage, electric current in this curve.
A kind of LED temperature control system based on PWM; Comprise that at least one drives the loop; It is characterized in that: also comprise control circuit; Said control circuit comprises that at least one brightness detects loop and a controller, and said brightness detects the loop and is connected with controller, and said controller is connected with the driving loop.
Said control circuit also comprises an AD converter, and said AD converter independently is arranged in the control circuit, and an end detects the loop with brightness and is connected, and the other end is connected with controller; Perhaps said AD converter is directly to be integrated in the controller.
It is a bridge-type bleeder circuit that said brightness detects the loop, comprises a photo resistance or a light-sensitive semiconductor element at least, and the bleeder circuit at said photo resistance or light-sensitive semiconductor element place is connected with controller.
Said bridge-type bleeder circuit is by photo resistance or light-sensitive semiconductor element and three four arm electrical bridges that resistance is formed.
Said controller is a single-chip microcomputer.
Said controller is provided with at least one voltage detecting end and at least one pwm signal output.
In sum, LED temperature-controlled process and the system based on PWM provided by the present invention can make LED in suitable temperature range, work, give full play to its optical efficiency, and can realize that LED brightness and optical efficiency, temperature reach optimum balance.LED temperature control system of the present invention is simple in structure, with low cost.
Description of drawings
Fig. 1 is the control circuit figure in the embodiment of the invention;
Fig. 2 is the flow chart of control method of the present invention.
Wherein, 1, photo resistance; 2, resistance; 3, be built-in with the controller of AD converter; 4, switching tube; 5, LED.
Embodiment
Below in conjunction with accompanying drawing and embodiment the present invention is described further:
As shown in Figure 1: a kind of LED temperature control system based on PWM, comprise that one drives the loop, is characterized in that: also comprise control circuit, said control circuit detects loop and a controller 3 by a brightness, is integrated with AD converter in the said controller 3; The voltage output end that said brightness detects the loop is connected with the voltage detecting end of controller 3, and said driving loop is connected with the pwm signal output of controller 3.
Said brightness detects the loop and forms a four arm electrical bridge bleeder circuit by a photo resistance 1 and three resistance 2, and the bleeder circuit at photo resistance 1 place is connected with controller 3.
Said driving loop is made up of with the switching tube 4 of control LED5 LED5, and the negative electrode of said LED5 is connected with the collector electrode of switching tube 4, and the base stage of switching tube 4 is connected the grounded emitter of switching tube 4 with the PWM output of controller 3.Drive the loop and also can adopt other common structural, like other switching devices such as employing metal-oxide-semiconductors, or the driving loop of employing and this driving loop structure antithesis etc.
Said controller 3 is a single-chip microcomputer, and single-chip microcomputer is provided with a voltage detecting end and a pwm signal output.
As shown in Figure 2, a kind of control method according to the described temperature control system of Fig. 1 is characterized in that, may further comprise the steps:
A, brightness detect the loop and detect the voltage U 1 of photo resistance 1 and voltage U 1 is outputed to the controller 3 that is built-in with AD converter, are calculated the brightness of LED5 again according to voltage U 1 by controller 3;
B, controller 3 calculate the current total power consumption W1 of LED5 according to PWM duty ratio d1 in the current control circuit, and controller 3 carries out power consumption with current total power consumption W1 tables look-up, and find out the optical efficiency η 1 that LED5 should reach when current total power consumption W1;
The brightness of the LED5 that c, controller 3 calculate according to step a and the current total power consumption W1 of the LED5 that step b calculates calculate the optical efficiency η 2 of LED5 in the current system;
D, comparison η 1 and η 2; If η 2＜η 1; Then controller 3 is inquired about according to the temperature-luminous efficiency curve tables of data in 2 pairs of controllers 3 of η, and a sets of curves that finds optical efficiency to equate with η 2 filters out the total power consumption point lower than current total power consumption W1 simultaneously in this sets of curves; If η 2=η 1, then controller 3 is not done any adjustment, and time-delay a period of time is detected again;
If e finds the point described in the steps d; Controller 3 calculates PWM duty ratio d2 according to the total power consumption W2 of this point; And according to the PWM output signal of duty ratio d2 adjustment control LED5, and PWM is exported signal output to drive circuit, thereby the Kai Heguan of control switch pipe 4 driving LED 5; If do not find the point described in the steps d, then controller 3 is not done any adjustment, and time-delay a period of time is detected again.
Said temperature-luminous efficiency curve is a sets of curves relevant with the LED self character, and different LED has the different characteristic curve, is obtained by the test in early stage, comprises parameter optical efficiency, total power consumption, temperature, voltage, electric current in this curve.
In addition, detect the loop and drive the different of loop quantity according to brightness, the optical efficiency that calculates according to detected voltage among the step a has the Different control mode:
(1) if each LED unit has a brightness to detect loop and a plurality of drivings loop in the LED temperature control system, the optical efficiency of then being calculated by the detected potentiometer in brightness detection loop will be controlled a plurality of drivings loop simultaneously, i.e. one-to-many control.
(2) if each in each LED unit drives corresponding respectively brightness detection loop, loop in the LED temperature control system; Then detected many group voltage needs to handle respectively; And calculate the corresponding driving loop of corresponding optical efficiency control respectively, promptly control one to one.
Have only a brightness to detect loop and a driving loop in the present embodiment, drive the loop so the optical efficiency that calculates is only controlled one, i.e. control one to one.
Though describe in detail, be not to be qualification to this patent protection range in conjunction with the specific embodiment specific embodiments of the invention.In claims institute restricted portion, various modifications that those skilled in the art can make without creative work or adjustment still receive the protection of this patent.
Claims (8)
1. the LED temperature-controlled process based on PWM is characterized in that, may further comprise the steps:
A, brightness detect the voltage U 1 of loop detection photo resistance or light-sensitive semiconductor element and voltage U 1 are outputed to AD converter and outputs to controller by AD converter again, are calculated the brightness of LED then according to voltage U 1 by controller; Perhaps directly voltage U 1 is outputed to the controller that is built-in with AD converter, calculate the brightness of LED again by controller according to voltage U 1;
B, controller calculate the current total power consumption W1 of LED according to PWM duty ratio d1 in the current control circuit, and controller carries out power consumption with current total power consumption W1 tables look-up, and find out the optical efficiency η 1 that LED should reach when current total power consumption W1;
The brightness of the LED that c, controller calculate according to step a and the current total power consumption W1 of the LED that step b calculates calculate the optical efficiency η 2 of LED in the current system;
D, comparison η 1 and η 2; If η 2＜η 1; Then controller is inquired about according to the temperature-luminous efficiency curve tables of data in 2 pairs of controllers of η, and a sets of curves that finds optical efficiency to equate with η 2 filters out the total power consumption point lower than current total power consumption W1 simultaneously in this sets of curves; If η 2=η 1, then controller is not done any adjustment, and time-delay a period of time is detected again;
If e finds the point described in the steps d, controller calculates PWM duty ratio d2 according to the total power consumption W2 of this point, and according to the PWM output signal of duty ratio d2 adjustment control LED, and PWM is exported signal outputs to drive circuit; If do not find the point described in the steps d, then controller is not done any adjustment, and time-delay a period of time is detected again.
2. the LED temperature-controlled process based on PWM according to claim 1 is characterized in that: said temperature-luminous efficiency curve is a sets of curves relevant with the LED self character, comprises parameter optical efficiency, total power consumption, temperature, voltage, electric current in this curve.
3. LED temperature control system based on PWM; Comprise that at least one drives the loop; It is characterized in that: also comprise control circuit; Said control circuit comprises that at least one brightness detects loop and a controller, and said brightness detects the loop and is connected with controller, and said controller is connected with the driving loop.
4. the LED temperature control system based on PWM according to claim 3; It is characterized in that: said control circuit also comprises an AD converter; Said AD converter independently is arranged in the control circuit, and an end detects the loop with brightness and is connected, and the other end is connected with controller; Perhaps said AD converter is directly to be integrated in the controller.
5. the LED temperature control system based on PWM according to claim 3; It is characterized in that: it is a bridge-type bleeder circuit that said brightness detects the loop; At least comprise a photo resistance or a light-sensitive semiconductor element, the bleeder circuit at said photo resistance or light-sensitive semiconductor element place is connected with controller.
6. the LED temperature control system based on PWM according to claim 5 is characterized in that: said bridge-type bleeder circuit is by photo resistance or light-sensitive semiconductor element and three four arm electrical bridges that resistance is formed.
7. the LED temperature control system based on PWM according to claim 3 is characterized in that: said controller is a single-chip microcomputer.
8. the LED temperature control system based on PWM according to claim 3 is characterized in that: said controller is provided with at least one voltage detecting end and at least one pwm signal output.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
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| CN201210045322.9A CN102595732B (en) | 2012-02-27 | 2012-02-27 | LED (light-emitting diode) temperature control method and system based on PWM (pulse width modulation) |
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| CN201210045322.9A CN102595732B (en) | 2012-02-27 | 2012-02-27 | LED (light-emitting diode) temperature control method and system based on PWM (pulse width modulation) |
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Cited By (6)
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| CN102883506A (en) * | 2012-09-21 | 2013-01-16 | 东南大学 | Method for dynamically controlling temperature of central area of array light emitting diode (LED) lighting lamp |
| CN103458575A (en) * | 2013-08-22 | 2013-12-18 | 广西奥顺仪器有限公司 | Digital linear dimming method for high-power LED |
| CN103781228A (en) * | 2012-10-24 | 2014-05-07 | 深圳市鑫田威尔科技有限公司 | LED industrial and mineral lamp and circuit control method thereof |
| CN105050263A (en) * | 2015-07-15 | 2015-11-11 | 广东融能科技有限公司 | Time-sharing automatic dimming system and method for light-emitting diode (LED) street lamp |
| CN107027213A (en) * | 2017-03-06 | 2017-08-08 | 广东德洛斯照明工业有限公司 | A kind of intelligent constant luminance output control method |
| CN107302814A (en) * | 2016-04-15 | 2017-10-27 | 英飞凌科技奥地利有限公司 | Temperature protection circuit for light emitting diode |
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Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102883506A (en) * | 2012-09-21 | 2013-01-16 | 东南大学 | Method for dynamically controlling temperature of central area of array light emitting diode (LED) lighting lamp |
| CN103781228A (en) * | 2012-10-24 | 2014-05-07 | 深圳市鑫田威尔科技有限公司 | LED industrial and mineral lamp and circuit control method thereof |
| CN103458575A (en) * | 2013-08-22 | 2013-12-18 | 广西奥顺仪器有限公司 | Digital linear dimming method for high-power LED |
| CN103458575B (en) * | 2013-08-22 | 2016-05-18 | 广西奥顺仪器有限公司 | Great power LED digital linear light-dimming method |
| CN105050263A (en) * | 2015-07-15 | 2015-11-11 | 广东融能科技有限公司 | Time-sharing automatic dimming system and method for light-emitting diode (LED) street lamp |
| CN107302814A (en) * | 2016-04-15 | 2017-10-27 | 英飞凌科技奥地利有限公司 | Temperature protection circuit for light emitting diode |
| CN107302814B (en) * | 2016-04-15 | 2019-11-01 | 英飞凌科技奥地利有限公司 | Temperature protection circuit for light emitting diode |
| CN107027213A (en) * | 2017-03-06 | 2017-08-08 | 广东德洛斯照明工业有限公司 | A kind of intelligent constant luminance output control method |
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