CN104252847A - Light emitting module and control method - Google Patents

Abstract

Provided are a light emitting module and a control method thereof. The light-emitting module includes a power supply, first and second light-emitting parts respectively connected between the power supply and the common voltage terminal, the first light-emitting part includes a first switch unit and a first light-emitting unit connected in series, and the second light-emitting part includes a second light-emitting part connected in series The switch unit and the second light emitting unit, the first and second switch units respectively control the first and second light emitting units to emit light alternately according to the first and second PWM control signals. The light emitting module also includes a working time monitoring unit and a control unit for recording the working time of the light emitting module, and the control unit adjusts the duty cycle of the first and second PWM control signals according to the working time of the light emitting module based on the first control information table. The light-emitting module further includes a third switch unit, the control unit outputs a switch control signal according to the working time of the light-emitting module based on the second control information table, and the third switch unit provides additional current to the first and second light-emitting units respectively according to the switch control signal.

Description

Light emitting module and control method thereof

technical field

The present invention relates to the technical field of light emitting modules, and more particularly relates to a light emitting module and a control method thereof.

Background technique

At present, for a liquid crystal display LCD, its lifespan mainly depends on the lifespan of a backlight module. Usually, the selling price of LCD with long life is high, and the life of common LCD is 5 years. At present, it is difficult to find an LCD with a life span of 15 years in the market, that is, it has been in the display state for 15 years.

On the other hand, since the luminous brightness of the light-emitting device in the backlight module tends to decrease with the increase of the working time, that is, the luminous luminance decreases under the same driving current, so as the working time increases, the brightness of the backlight produced by the backlight module will decrease. It also gradually decreases, which also affects the display effect of the LCD.

Therefore, there is a need for a light-emitting module that can be applied to a backlight module and a control method thereof, which not only has a long working life, but also can provide a good display effect during the long working life.

Contents of the invention

The present invention has been made in consideration of the above-mentioned problems. The purpose of the present invention is to provide a light-emitting module and its control method, which can effectively prolong the working time of these two groups of light-emitting units (correspondingly, the light-emitting module) under the condition of ensuring the display brightness by using two groups of light-emitting units to emit light alternately. life. Furthermore, the light-emitting module and its control method can also adjust the duty cycle of the two PWM control signals used to control the two groups of light-emitting units according to the working time of the light-emitting module, so that as the working time increases, the PWM control can be appropriately increased. The duration of the effective control level of a signal so that a constant brightness can be maintained. Furthermore, the light-emitting module and its control method can also increase the magnitude of the driving current flowing through the light-emitting unit when the working time of the light-emitting module exceeds a predetermined threshold, so that it can effectively compensate for the aging of the light-emitting unit under the same driving current. The problem of reduced luminous brightness.

According to a first aspect of the present invention, there is provided a light emitting module, including: a power supply for supplying a power supply voltage; a first light emitting part, which includes a first resistor unit, a first switch unit, and a first light emitting unit connected in series, The first end of the first light emitting part is connected to the power supply, the second end of the first light emitting part is connected to the common voltage end; and the second light emitting part includes a second resistor unit and a second switch unit connected in series , and a second light emitting unit, the first end of the second light emitting part is connected to the power supply, the second end of the second light emitting part is connected to the common voltage end, wherein the control end of the first switch unit receives the first a PWM control signal, and control the first light-emitting unit to emit light when the first PWM control signal is at an effective control level, the control terminal of the second switch unit receives the second PWM control signal, and when the second PWM control signal is at When the level is effectively controlled, the second light-emitting unit is controlled to emit light, and under the control of the first PWM control signal and the second PWM control signal, the first light-emitting unit and the second light-emitting unit alternately emit light.

Preferably, the resistance of the first resistance unit is the same as the resistance of the second resistance unit, the periods of the first PWM control signal and the second PWM control signal are the same, and the phase difference between the first PWM control signal and the second PWM control signal is 180°, the durations of the effective control levels of the first PWM control signal and the second PWM control signal are the same and less than half of the period of the first PWM control signal and the second PWM control signal.

According to the second aspect of the present invention, there is provided a light emitting module, comprising: a power supply for supplying a power supply voltage; a first light emitting part comprising a first resistance unit connected in series between the power supply and a common voltage terminal, A first switch unit and a first light-emitting unit; a second light-emitting part, which includes a second resistance unit connected in series between the power supply and a common voltage terminal, a second switch unit, and a second light-emitting unit; a working time monitoring unit , for recording the working time of the light-emitting module; and a control unit, for receiving the working time recorded by the working time monitoring unit, and based on the first control information table, adjusting the second working time according to the received working time A duration of effective control levels of the PWM control signal and the second PWM control signal, wherein the first control information table stores the working time and the duration of the effective control levels of the first and second PWM control signals The corresponding relationship of time, the control terminal of the first switch unit receives the first PWM control signal, and controls the first light-emitting unit to emit light when the first PWM control signal is at an effective control level, and the control terminal of the second switch unit receives the second PWM control signal, and control the second light emitting unit to emit light when the second PWM control signal is at an effective control level.

According to a third aspect of the present invention, there is provided a light emitting module, comprising: a power supply for supplying a power supply voltage; a first light emitting part comprising a first resistor unit connected in series between the power supply and a common voltage terminal, A first switch unit and a first light-emitting unit; a second light-emitting part, which includes a second resistance unit connected in series between the power supply and a common voltage terminal, a second switch unit, and a second light-emitting unit; a working time monitoring unit , for recording the working time of the light-emitting module; the control unit is used for receiving the working time recorded by the working time monitoring unit, and based on the second control information table, outputting a switch control signal according to the received working time; and The first end and the second end of the third switch unit are respectively connected to the first end and the second end of the first resistance unit, and the third end and the fourth end are respectively connected to the second end of the second resistance unit. The first terminal is connected to the second terminal, and its control terminal receives the switch control signal, wherein, when the switch control signal is at an effective control level, the third switch unit connects its first terminal and the second terminal The electrical connection between and the electrical connection between the third terminal and the fourth terminal.

The control terminal of the first switch unit receives the first PWM control signal, and controls the first light emitting unit to emit light when the first PWM control signal is at an effective control level, the control terminal of the second switch unit receives the second PWM control signal, and The second light emitting unit is controlled to emit light when the second PWM control signal is at an effective control level.

According to a fourth aspect of the present invention, there is provided a light emitting module, comprising: a power supply for supplying a power supply voltage; a first light emitting part comprising a first resistor unit connected in series between the power supply and a common voltage terminal, A first switch unit and a first light-emitting unit; a second light-emitting part, which includes a second resistance unit connected in series between the power supply and a common voltage terminal, a second switch unit, and a second light-emitting unit; a working time monitoring unit , for recording the working time of the light-emitting module; the control unit is used for receiving the working time recorded by the working time monitoring unit, based on the second control information table, outputting the switch control signal according to the received working time, and also Based on the first control information table, adjust the duration of the effective control level of the first PWM control signal and the second PWM control signal according to the received working time; and the third switch unit, the first terminal and The second end is respectively connected with the first end and the second end of the first resistance unit, and its third end and the fourth end are respectively connected with the first end and the second end of the second resistance unit, and its control The terminal receives the switch control signal, wherein, when the switch control signal is at an effective control level, the third switch unit turns on the electrical connection between its first terminal and the second terminal and its third terminal and the third terminal. The electrical connection between the four terminals.

The first control information table stores the corresponding relationship between the working time and the duration of the effective control levels of the first and second PWM control signals, the control terminal of the first switch unit receives the first PWM control signal, and When the first PWM control signal is at an effective control level, the first light-emitting unit is controlled to emit light, and the control terminal of the second switch unit receives the second PWM control signal, and controls the second PWM control signal when the second PWM control signal is at an effective control level. The light emitting unit emits light.

According to the fifth aspect of the present invention, there is provided a driving method applied to the light-emitting module according to the first aspect of the present invention, comprising: the control terminal of the first switch unit receives a first PWM control signal, and When the signal is at an effective control level, control the first light-emitting unit to emit light; the control terminal of the second switch unit receives the second PWM control signal, and controls the second light-emitting unit to emit light when the second PWM control signal is at an effective control level, wherein, Under the control of the first PWM control signal and the second PWM control signal, the first light emitting unit and the second light emitting unit emit light alternately.

According to the sixth aspect of the present invention, there is provided a driving method applied to the light-emitting module according to the second aspect of the present invention, including: recording the working time of the light-emitting module through the working time monitoring unit; based on the first control information table, the control unit according to The received working time is used to adjust the duration of the effective control level of the first PWM control signal and the second PWM control signal; the control terminal of the first switch unit receives the first PWM control signal, and in the first PWM When the control signal is at an effective control level, control the first light-emitting unit to emit light; the control terminal of the second switch unit receives the second PWM control signal, and controls the second light-emitting unit to emit light when the second PWM control signal is at an effective control level, wherein , the first control information table stores the corresponding relationship between the working time and the duration of the effective control levels of the first and second PWM control signals, in the first PWM control signal and the second PWM control signal Under control, the first light emitting unit and the second light emitting unit emit light alternately.

According to the seventh aspect of the present invention, there is provided a driving method applied to the light-emitting module according to the third aspect of the present invention, including: recording the working time of the light-emitting module through the working time monitoring unit; based on the second control information table, the control unit according to The received working time outputs a switch control signal; the control terminal of the third switch unit receives the switch control signal, and when the switch control signal is at an effective control level, the third switch unit connects its first terminal and the second switch unit. The electrical connection between the two terminals and the electrical connection between the third terminal and the fourth terminal; the control terminal of the first switch unit receives the first PWM control signal, and when the first PWM control signal is at an effective control level Control the first light-emitting unit to emit light; the control terminal of the second switch unit receives the second PWM control signal, and controls the second light-emitting unit to emit light when the second PWM control signal is at an effective control level, wherein, in the first PWM Under the control of the control signal and the second PWM control signal, the first light emitting unit and the second light emitting unit emit light alternately.

According to the eighth aspect of the present invention, there is provided a driving method applied to the light-emitting module according to the fourth aspect of the present invention, including: recording the working time of the light-emitting module through the working time monitoring unit; based on the second control information table, the control unit according to The received working time outputs a switch control signal; the control terminal of the third switch unit receives the switch control signal, and when the switch control signal is at an effective control level, the third switch unit connects its first terminal and the second switch unit. The electrical connection between the two terminals and the electrical connection between the third terminal and the fourth terminal; based on the first control information table, the control unit adjusts the first PWM control signal and the second PWM control signal according to the received working time The duration of the effective control level of the control signal; the control terminal of the first switch unit receives the first PWM control signal, and controls the first light emitting unit to emit light when the first PWM control signal is at the effective control level; the second switch unit The control terminal of the control terminal receives the second PWM control signal, and controls the second light-emitting unit to emit light when the second PWM control signal is at an effective control level, wherein the first control information table stores the working time and the first and The corresponding relationship between the duration of the effective control level of the second PWM control signal, under the control of the first PWM control signal and the second PWM control signal, the first light emitting unit and the second light emitting unit emit light alternately .

According to the light-emitting module and the driving method of various aspects of the present invention, on the one hand, by controlling the first light-emitting unit and the second light-emitting unit to emit light alternately; The second terminal and the third terminal and the fourth terminal that are connected to the third switch unit, that is, when the working time of the light emitting module exceeds the first working time threshold, the third switch unit additionally supplies the first light emitting unit and the second The light-emitting unit provides current; on the other hand, by adjusting the duration of the effective control level of the first PWM control signal and the second PWM control signal according to the received working time, that is, as the working time increases, according to the predetermined The relationship increases the duration of the effective control levels of the first PWM control signal and the second PWM control signal, which can better compensate for the decrease in luminous brightness of the light emitting device caused by the same driving current caused by the increase of the working time of the light emitting device.

Description of drawings

Various features and advantages of the embodiments of the present invention will be more apparent and easier to understand by describing embodiments of the present invention with reference to the accompanying drawings, in which:

Fig. 1 shows a schematic block diagram of a first example of a lighting module according to a first embodiment of the present invention;

Fig. 2 shows a schematic block diagram of a second example of a lighting module according to the first embodiment of the present invention;

Fig. 3 shows a schematic block diagram of a first example of a lighting module according to a second embodiment of the present invention;

Fig. 4 shows a schematic block diagram of a second example of a lighting module according to a second embodiment of the present invention;

Fig. 5 shows an example implementation of a light emitting module according to a second embodiment of the present invention;

FIG. 6 shows an exemplary timing diagram of a first PWM control signal and a second PWM control signal according to an embodiment of the present invention;

Fig. 7 shows a flowchart of a method for controlling a light emitting module according to a first embodiment of the present invention;

Fig. 8 shows a flowchart of a method for controlling a light emitting module according to a second embodiment of the present invention;

Fig. 9 shows a flowchart of a method for controlling a light emitting module according to a third embodiment of the present invention; and

Fig. 10 shows a flowchart of a method for controlling a light emitting module according to a fourth embodiment of the present invention.

Specific implementation

The light emitting module according to the embodiment of the present invention will be described first with reference to FIGS. 1-5 .

The light-emitting module according to the first embodiment of the present invention includes a power supply, a first light-emitting part, and a second light-emitting part, and the first light-emitting part includes a first resistance unit, a first switch unit, and a first light-emitting unit connected in series, so The second light emitting part includes a second resistance unit, a second switch unit and a second light emitting unit connected in series, the first ends of the first light emitting part and the second light emitting part are connected to the power supply and the second ends Both are connected to the common voltage terminal. The control terminal of the first switch unit receives the first PWM control signal, and controls the first light emitting unit to emit light when the first PWM control signal is at an effective control level, the control terminal of the second switch unit receives the second PWM control signal, and When the second PWM control signal is at an effective control level, the second light-emitting unit is controlled to emit light, and under the control of the first PWM control signal and the second PWM control signal, the first light-emitting unit and the second The light emitting units emit light alternately.

Fig. 1 and Fig. 2 respectively show schematic block diagrams of a first example and a second example of a light emitting module according to the first embodiment of the present invention.

As shown in Figure 1, the light emitting module includes a power supply 101, a first light emitting part, and a second light emitting part, and the first light emitting part includes a first resistance unit 102, a first light emitting unit 104 and a first light emitting unit connected in series in sequence. The switch unit 106 , the second light emitting part includes a second resistance unit 103 , a second light emitting unit 105 and a second switch unit 107 sequentially connected in series.

A first end of the first resistance unit 102 is connected to the power supply, and a second end of the first resistance unit 102 is connected to the first end of the first light emitting unit 104 . A first end of the second resistance unit 103 is connected to the power supply, and a second end of the second resistance unit 103 is connected to the first end of the second light emitting unit 105 . Preferably, the resistance of the first resistance unit 102 is equal to the resistance of the second resistance unit 103 .

The first terminal of the first switch unit 106 is connected to the second terminal of the first light emitting unit 104, the second terminal of the first switch unit 106 is connected to the common voltage terminal, and the control terminal of the first switch unit 106 receives the first PWM control signal. The first switch unit 106 controls the first light emitting unit 104 to emit light when the first PWM control signal is at an effective control level.

The first terminal of the second switch unit 107 is connected to the second terminal of the second light emitting unit 105, the second terminal of the second switch unit 107 is connected to the common voltage terminal, and the control terminal of the second switch unit 107 receives the second PWM control signal. The second switch unit 107 controls the second light emitting unit to emit light when the second PWM control signal is at an effective control level.

As shown in Figure 2, the light emitting module also includes a power supply 101, a first light emitting part, and a second light emitting part, and the first light emitting part includes a first resistance unit 102, a first switch unit 106 and a second light emitting unit connected in series in sequence. A light emitting unit 104 , the second light emitting part includes a second resistor unit 103 , a second switch unit 107 and a second light emitting unit 105 connected in series in sequence.

A first end of the first resistance unit 102 is connected to the power supply, and a second end of the first resistance unit 102 is connected to the first end of the first switch unit 106 . A first end of the second resistance unit 103 is connected to the power supply, and a second end of the second resistance unit 103 is connected to the first end of the second switch unit 107 . Preferably, the resistance of the first resistance unit 102 is equal to the resistance of the second resistance unit 103 .

The second end of the first switch unit 106 is connected to the first end of the first light emitting unit 104, and the control end of the first switch unit 106 receives the first PWM control signal, and the second end of the first light emitting unit 104 is connected to the common voltage end . The first switch unit 106 controls the first light emitting unit 104 to emit light when the first PWM control signal is at an effective control level.

The second end of the second switch unit 107 is connected to the first end of the second light emitting unit 105, and the control end of the second switch unit 107 receives the second PWM control signal, and the second end of the second light emitting unit 105 is connected to the common voltage end . The second switch unit 107 controls the second light emitting unit 105 to emit light when the second PWM control signal is at an effective control level.

Only two examples of lighting modules according to the first embodiment of the present invention are shown in FIGS. 1 and 2 . However, the first embodiment of the present invention is not limited thereto, and the first resistance unit 102, the first light emitting unit 104, and the first switch unit 106 may be connected in series between the power supply 101 and the common voltage terminal in any order, and the second resistance unit 103, the second light emitting unit 105, and the second switch unit 107 can be connected in series between the power supply 101 and the common voltage terminal in any order, and the series connection of the first resistance unit 102, the first light emitting unit 104 and the first switch unit 106 The order may be different from the series order of the second resistor unit 103 , the second light emitting unit 105 and the second switch unit 107 .

Advantageously, the first resistance unit 102 and the second resistance unit 103 have the same equivalent circuit structure, that is, the resistance of the first resistance unit 102 is the same as the resistance of the second resistance unit 103, the first switch unit 106 and the second switch The unit 107 has the same equivalent circuit structure, and the first light emitting unit 104 and the second light emitting unit 105 also have the same equivalent circuit structure. More advantageously, the first resistance unit 102 and the second resistance unit 103 have the same/symmetrical circuit structure, the first switch unit 106 and the second switch unit 107 have the same/symmetrical circuit structure, the first light emitting unit 104 and the second The two light emitting units 105 also have the same/symmetrical circuit structure.

In order to make the first light-emitting unit 104 in the first light-emitting part and the second light-emitting unit 105 in the second light-emitting part have substantially the same working time (that is, basically the same aging degree), advantageously, the first PWM control signal and the second The periods of the PWM control signals are the same, and the durations of the active control levels of the first PWM control signal and the second PWM control signal are also the same.

The effective control level of the first PWM control signal may be the same as the effective control level of the second PWM control signal. For example, both the first PWM control signal and the second PWM control signal are active high. In this case, the duration of the active control levels of the first PWM control signal and the second PWM control signal may be equivalent to the duty cycle of the first PWM control signal and the second PWM control signal. Alternatively, both the first PWM control signal and the second PWM control signal may be active low.

In this case, in order to make the light-emitting brightness of the light-emitting module according to the first embodiment of the present invention uniform, advantageously, the phase difference between the first PWM control signal and the second PWM control signal is 180°, and the first PWM control signal and the second PWM control signal The duration of the active control level of the PWM control signal is less than half of the period of the first PWM control signal and the second PWM control signal. FIG. 6 shows an exemplary timing diagram when the effective control levels of the first PWM control signal and the second PWM control signal are both high.

The effective control level of the first PWM control signal may be different from the effective control level of the second PWM control signal. For example, the first PWM control signal is active high, while the second PWM control signal is active low. In this case, the duration of the active control level of the first PWM control signal is equivalent to the duration of its high level, and the duration of the active control level of the second PWM control signal is equivalent to its low level duration, and vice versa.

In this case, in order to make the light-emitting brightness of the light-emitting module according to the first embodiment of the present invention uniform, it is advantageous that the start time of the effective control level of the first PWM control signal and the start time of the effective control level of the second PWM control signal The start time phase difference is 180°, the end time phase of the effective control level of the first PWM control signal and the end time phase difference of the effective control level of the second PWM control signal are also 180°, and the first PWM control signal and the second PWM control signal The durations of the effective control levels of the two PWM control signals are less than half of the periods of the first PWM control signal and the second PWM control signal.

In addition, the two examples of the light emitting module according to the first embodiment of the present invention shown in FIG. 1 and FIG. 2 may further include a working time monitoring unit (not shown) and a control unit 110 .

The working time monitoring unit records the working time of the light emitting module. The control unit 110 receives the working time recorded by the working time monitoring unit, and based on the first control information table, adjusts the effective control levels of the first PWM control signal and the second PWM control signal according to the received working time duration.

It is known that the luminous brightness of the light-emitting device perceived by the human eye is determined by the time during which the driving current flows through the light-emitting device in each cycle and the magnitude of the driving current. The magnitude of the driving current directly determines the instantaneous luminous brightness of the light emitting device, and the time during which the driving current flows through the light emitting device directly determines the light emitting time of the light emitting device. That is to say, the luminous brightness of the light-emitting device perceived by human eyes is determined by the light-emitting time of the light-emitting device in each cycle and the instantaneous luminous brightness of the light-emitting device.

However, as the working time of the light emitting device increases (ie, the aging degree increases), the instantaneous luminous brightness generated by the same driving current flowing through the light emitting device decreases. According to the first embodiment of the present invention, the instantaneous decrease in luminous brightness caused by the same driving current flowing through the light emitting device is compensated by prolonging the light emitting time of the light emitting device in each cycle.

The corresponding relationship between the working time of the light-emitting device and the instantaneous luminous brightness under the same driving current can be obtained in advance, and the relationship between the working time of the light-emitting device and the light-emitting time of the light-emitting device in each cycle can be obtained accordingly, and such a relationship can be stored in In the first control information table. Therefore, in the light emitting module according to the first embodiment of the present invention, by referring to the first control information table, as the working time of the light emitting device increases (the degree of aging increases), the control unit 110 can prolong the operation of the light emitting device in each cycle. The light-emitting time is used to compensate for the instantaneous decrease in luminous brightness caused by the same driving current flowing through the light-emitting device, thereby effectively improving the display effect.

In the following, in order to simplify the description, the effective control level of the first PWM control signal and the effective control level of the second PWM control signal are both high levels as an example to expand the description.

For example, the initial duty cycle of the first PWM control signal and the second PWM control signal can be set as the first duty cycle (for example, 20-30%), and gradually increase the first duty cycle as the working time of the light-emitting module increases. The duty cycle of the PWM control signal and the second PWM control signal until reaching a first duty cycle threshold (eg lower than 50%). For example, the duty ratios of the first PWM control signal and the second PWM control signal may be increased in units of years, and the duty ratios of the first PWM control signal and the second PWM control signal are increased by a predetermined percentage every year. Advantageously, the duty cycles of the first PWM control signal and the second PWM control signal are both less than 50%, so as to ensure that the lighting times of the first light emitting unit 104 and the second light emitting unit 105 do not overlap with each other.

Fig. 3 and Fig. 4 respectively show schematic block diagrams of a first example and a second example of a light emitting module according to a second embodiment of the present invention.

The light emitting module according to the second embodiment of the present invention includes a third switch unit 108 in addition to the light emitting module according to the first embodiment of the present invention.

The first end of the third switch unit 108 is connected to the first end of the first resistance unit 102, the second end of the third switch unit 108 is connected to the second end of the first resistance unit 102, and the third end of the third switch unit 108 terminal is connected to the first terminal of the second resistance unit 103, the fourth terminal of the third switch unit 108 is connected to the second terminal 104 of the second resistance unit, and the control terminal of the third switch unit 108 receives a switch control signal.

When the switch control signal is at an effective control level, the third switch unit 108 turns on the electrical connection between its first terminal and its second terminal and the electrical connection between its third terminal and its fourth terminal.

Advantageously, the circuit between the first terminal and the second terminal of the third switch unit 108 and the circuit between the third terminal and the fourth terminal of the third switch unit 108 have the same equivalent circuit structure, that is, the third The resistance between the first end and the second end of the switch unit 108 is equal to the resistance between the third end and the fourth end of the third switch unit 108 . More advantageously, the circuit between the first terminal and the second terminal of the third switch unit 108 and the circuit between the third terminal and the fourth terminal of the third switch unit 108 have the same/symmetrical circuit structure.

As shown in FIG. 3, the first light-emitting part includes a first resistance unit 102, a first light-emitting unit 104, and a first switch unit 106 connected in series in sequence, and the second light-emitting part includes a second resistance unit connected in series in sequence. 103 , the second light emitting unit 105 and the second switch unit 107 . Except for the addition of the third switch unit 108 , the light emitting module shown in FIG. 3 is the same as the light emitting module shown in FIG. 1 , which will not be repeated here.

As shown in FIG. 3, the first terminal (also the third terminal) of the third switch unit 108 is connected to the power supply 101, the second terminal of the third switch unit 108 is connected to the first terminal of the first light emitting unit 104, The fourth terminal of the third switch unit 108 is connected to the second terminal of the second light emitting unit 105, and the control terminal of the third switch unit 108 receives the switch control signal.

As shown in FIG. 4, the first light-emitting part includes a first resistance unit 102, a first switch unit 106, and a first light-emitting unit 104 connected in series in sequence, and the second light-emitting part includes a second resistance unit connected in series in sequence. 103 , a second switch unit 107 and a second light emitting unit 105 . Except for the addition of the third switch unit 108 , the light emitting module shown in FIG. 4 is the same as the light emitting module shown in FIG. 2 , which will not be repeated here.

As shown in FIG. 4, the first end (also the third end) of the third switch unit 108 is connected to the power supply 101, the second end of the third switch unit 108 is connected to the first end of the first switch unit 106, The fourth terminal of the third switch unit 108 is connected to the second terminal of the second switch unit 107, and the control terminal of the third switch unit 108 receives the switch control signal.

Only two examples of lighting modules according to the second embodiment of the invention are shown in FIGS. 3 and 4 . However, the second embodiment of the present invention is not limited thereto, and the first resistance unit 102, the first light emitting unit 104, and the first switch unit 106 may be connected in series between the power supply 101 and the common voltage terminal in any order, and the second resistance unit 103, the second light emitting unit 105, and the second switch unit 107 can be connected in series between the power supply 101 and the common voltage terminal in any order, and the series connection of the first resistance unit 102, the first light emitting unit 104 and the first switch unit 106 The order may be different from the series order of the second resistor unit 103 , the second light emitting unit 105 and the second switch unit 107 . Moreover, the first end and the third end of the third switch unit 108 can be different, as long as the first end of the third switch unit 108 is connected to the first end of the first resistance unit 102, and the second end of the third switch unit 108 is connected to The second end of the first resistance unit 102 is connected, the third end of the third switch unit 108 is connected to the first end of the second resistance unit 103, the fourth end of the third switch unit 108 is connected to the second end of the second resistance unit 104 connection is enough.

Same as the first embodiment of the present invention, in the second embodiment of the present invention, in order to make the first light-emitting unit 104 in the first light-emitting part and the second light-emitting unit 105 in the second light-emitting part have substantially the same working time (that is, Aging degree), advantageously, the periods of the first PWM control signal and the second PWM control signal are the same, and the durations of the effective control levels of the first PWM control signal and the second PWM control signal are also the same.

In addition, the lighting module according to the second embodiment of the present invention further includes a working time monitoring unit (not shown) and a control unit 110 .

The working time monitoring unit records the working time of the light emitting module. The control unit 110 receives the working time recorded by the working time monitoring unit, and based on the second control information table, outputs the switch control signal according to the received working time. When the switch control signal output by the control unit 110 is at an effective control level, the third switch unit 108 turns on the electrical connection between its first terminal and its second terminal and the electrical connection between its third terminal and its fourth terminal. connect.

To simplify the description, the following takes the effective control level of the switch control signal as a high level as an example to expand the description.

For example, the second control information table may include a first working time threshold (for example, 8 years, 10 years, etc.), and when the working time recorded by the working time monitoring unit is greater than the first working time threshold, the The switch control signal output by the control unit 110 is at a high level. The control terminal of the third switch unit 108 receives a high-level switch control signal, and connects the electrical connection between the first terminal and the second terminal and the electrical connection between the third terminal and the fourth terminal.

For another example, the second control information table may include a first working time threshold (for example, 7 years, 8 years, etc.) and a second working time threshold (such as 10 years, 12 years, etc.), the first working time threshold is less than the first working time threshold Two working time thresholds, the switch control signal output by the control unit 110 may include a first switch control signal and a second switch control signal, and the control terminal of the third switch unit may include a switch for receiving the first control signal A first control terminal and a second control terminal for receiving the second control signal.

In this case, when the working time recorded by the working time monitoring unit is greater than the first working time threshold and smaller than the second working time threshold, the first control signal is at a high level, and the second The second control signal is at a low level, there is a first resistor between the first terminal and the second terminal of the third switch unit, and the first resistor can flow between the first terminal and the second terminal of the third switch unit. current, thereby increasing the current flowing through the first light-emitting unit; there is also a first resistor between the third terminal and the fourth terminal of the third switch unit, and the third terminal and the fourth terminal of the third switch unit The first current may also flow between them, thereby increasing the current flowing through the second light emitting unit.

In this case, when the working time recorded by the working time monitoring unit is greater than the second working time threshold, the second control signal is at a high level, and the first terminal of the third switching unit and the There is a second resistance between the second terminals, there is a second resistance between the third terminal and the fourth terminal of the third switch unit, and the first resistance is greater than the second resistance. At this time, the second current may flow between the first end and the second end of the third switch unit, thereby increasing the current flowing through the first light emitting unit; between the third end and the fourth end of the third switch unit A second current may also flow between them, thereby increasing the current flowing through the second light emitting unit, and the second current is greater than the first current. In other words, as the working time of the light-emitting module increases, the driving current flowing through the light-emitting unit is controllably increased in stages, thereby compensating for the problem of instantaneous luminous brightness decrease caused by the same driving current caused by the aging of the light-emitting unit.

In addition, when the working time recorded by the working time monitoring unit is greater than the second working time threshold, the first control signal can be at a high level or at a low level, as long as it is ensured that in this case It only needs that the second resistance existing between the first end and the second end of the third switch unit is smaller than the first resistance.

In addition, in the light emitting module according to the second embodiment of the present invention, the control unit 110 can also adjust the validity of the first PWM control signal and the second PWM control signal according to the received working time based on the first control information table. Controls the duration of the level.

For example, when the working time of the light-emitting module is shorter than the first working time threshold, the control unit 110 adjusts the high levels of the first PWM control signal and the second PWM control signal according to the received working time based on the first control information table. The duration of the level (that is, the duty cycle), so as to realize the compensation for the aging degree of the light-emitting module.

As the working time of the light-emitting module increases, the duty ratios of the first PWM control signal and the second PWM control signal gradually increase, and gradually approach the duty ratio threshold (for example, 50%).

When the working time of the light-emitting module reaches the first working time threshold, the duty ratios of the first PWM control signal and the second PWM control signal are also closer to or reach the duty ratio threshold, and the control unit 110 starts to output high-level switch control signal, so that the third switch unit 108 starts to provide the first current to the first light emitting unit 104 and the second light emitting unit 105 respectively, so as to increase the driving current flowing through the first light emitting unit 104 and the second light emitting unit 105 respectively, thereby further Compensation for the aging degree of the light-emitting module is realized.

In the first control information table, the duty cycle of the PWM control signal before and after the first working time threshold may jump downward. For example, considering that the first working time threshold is 10 years, in the first control information table, the duty cycle of the PWM control signal corresponding to the first working time threshold may be 45%, but the PWM control signal corresponding to the working time of 11 years The duty cycle of the signal may be 30%, because the first current has been additionally supplied to the first light emitting unit 104 and the second light emitting unit 105 respectively through the third switch unit 108 .

The first control information table and the second control information table can be set according to experiments or experience, and the present invention is not limited by the forms of the first control information table and the second control information table.

An example implementation of the light emitting module shown in FIG. 3 is exemplarily shown in FIG. 5 .

As shown in Figure 5, the first resistance unit 102 includes resistors R11 and R12 connected in parallel, the first switch unit 106 includes a transistor T11 and resistors R191 and R192, the gate of the transistor T11 receives the first PWM control signal through R191, and the transistor T11 The source of the transistor T11 is connected to the common voltage terminal, which may be ground level, and the drain of the transistor T11 is connected to the second terminal of the first light emitting unit 104 .

As shown in Figure 5, the second resistance unit 103 includes resistors R21 and R22 connected in parallel, the second switch unit 107 includes a transistor T21 and resistors R291 and R292, the gate of the transistor T21 receives the second PWM control signal through R291, and the transistor T21 The source of the transistor T21 is connected to the common voltage terminal, and the drain of the transistor T21 is connected to the second terminal of the second light emitting unit 105 .

As shown in FIG. 5 , the third switch unit 108 includes a first part and a second part, the first part is connected to the first resistance unit, and the second part is connected to the second resistance unit. The first part includes transistors T12 and T13, resistors R13, R14, R15, R16, R17 and R18, and the second part includes transistors T22 and T23, resistors R23, R24, R25, R26, R27 and R28.

Transistors T11, T12, T13, T21, T22 and T23 may be MOS transistors, triodes and the like. As shown in FIG. 5 , transistors T13 and T23 are NMOS transistors, transistors T12 and T22 are PMOS transistors, and transistors T11 and T21 are NMOS transistors. However, the present invention is not limited thereto, and the transistors T11 , T12 , T13 , T21 , T22 and T23 may have different implementations according to specific implementations.

When the first PWM control signal is at a low level (inactive control level), T11 is turned off, no driving current flows through the first light emitting unit, and the first light emitting unit does not emit light. When the first PWM control signal is at a high level (effective control level), T11 is turned on, the driving current flows through the first light emitting unit, and the first light emitting unit emits light.

When the second PWM control signal is at a low level (inactive control level), T21 is turned off, no driving current flows through the second light emitting unit, and the second light emitting unit does not emit light. When the second PWM control signal is at a high level (effective control level), T21 is turned on, the driving current flows through the second light emitting unit, and the second light emitting unit emits light.

When the switch control signal is at low level (inactive control level), T13 , T12 , T23 and T22 are all off, so the third switch unit 108 does not provide current to the first light emitting unit 104 and the second light emitting unit 105 .

When the switch control signal is at a high level (effective control level), T13, T12, T23 and T22 are all turned on, thus the third switch unit 108 additionally provides current to the first light emitting unit 104 and the second light emitting unit 105 .

Although a specific implementation manner of the third switch unit 108 is shown in FIG. 5 , the present invention is not limited thereto, and those skilled in the art can obtain other implementation manners based on the concept of the present invention. For example, the 3V (high level) switching control signal output by the control unit 110 can be transformed into a voltage of eg 8V by using an amplifying circuit or a boosting circuit, and applied to the gate of the transistor T12 to control T12 to be turned on. In this case, T12 may also be an NMOS transistor, the drain of T12 is connected to the power supply, and the source of T12 is connected to the second terminal of the first resistance unit. In addition, the first switch unit 106 is not limited to the implementation shown in FIG. 5 , and a PMOS transistor may also be used as the effective control level of the first PWM control signal changes.

In the embodiment of the present invention, the first light emitting unit and the second light emitting unit may include LED devices as light emitting devices. Those skilled in the art should understand that the first light emitting unit and the second light emitting unit may also include devices having similar light emitting characteristics as light emitting devices.

The driving method of the light emitting module according to the embodiment of the present invention will be described below with reference to FIGS. 7-10 .

A method 700 for driving a light emitting module according to a first embodiment of the present invention is described with reference to FIG. 1 , FIG. 2 and FIG. 7 .

In step S710, the control terminal of the first switch unit receives the first PWM control signal, and controls the first light emitting unit to emit light when the first PWM control signal is at an effective control level.

In step S720, the control terminal of the second switch unit receives the second PWM control signal, and controls the second light emitting unit to emit light when the second PWM control signal is at an effective control level.

Under the control of the first PWM control signal and the second PWM control signal, the first light emitting unit and the second light emitting unit emit light alternately. By reasonably setting the period of the first PWM control signal and the second PWM control signal, for example, the period is less than 10ms, so that human eyes cannot feel the flickering of the first light-emitting unit and the second light-emitting unit, and the life of the light-emitting module can be extended to a certain extent. service life.

A method 800 for driving a light emitting module according to a second embodiment of the present invention will be described with reference to FIG. 1 , FIG. 2 and FIG. 8 .

In step S810, the working time of the light emitting module is recorded by the working time monitoring unit.

In step S820, based on the first control information table, the control unit adjusts the duration of the effective control levels of the first PWM control signal and the second PWM control signal according to the received working time. The first control information table stores the corresponding relationship between the working time and the duration of the effective control levels of the first and second PWM control signals.

In step S830, the control terminal of the first switch unit receives the first PWM control signal, and controls the first light emitting unit to emit light when the first PWM control signal is at an effective control level.

In step S840, the control terminal of the second switch unit receives the second PWM control signal, and controls the second light emitting unit to emit light when the second PWM control signal is at an effective control level.

By adjusting the duration of the effective control levels of the first PWM control signal and the second PWM control signal according to the received working time, that is, as the working time increases, the first PWM control signal and the second PWM control signal are increased according to a predetermined relationship. The duration of the effective control level of the second PWM control signal can compensate for the instantaneous decrease in luminous brightness of the light emitting device caused by the same driving current caused by the increase of the working time of the light emitting device.

A method 900 for driving a light emitting module according to a third embodiment of the present invention is described with reference to FIG. 1 , FIG. 2 and FIG. 9 .

In step S910, the working time of the light emitting module is recorded by the working time monitoring unit.

In step S920, based on the second control information table, the control unit outputs a switch control signal according to the received working time.

In step S930, the control terminal of the third switch unit receives the switch control signal, and when the switch control signal is at an effective control level, the third switch unit turns on the power between the first terminal and the second terminal. connection and electrical connection between its third and fourth terminals, and the resistance present between its first and second terminals is equal to the resistance present between its third and fourth terminals.

In step S940, the control terminal of the first switch unit receives the first PWM control signal, and controls the first light emitting unit to emit light when the first PWM control signal is at an effective control level.

In step S950, the control terminal of the second switch unit receives the second PWM control signal, and controls the second light emitting unit to emit light when the second PWM control signal is at an effective control level.

By controlling to turn on the first end and the second end of the third switch unit and turn on the third end and the fourth end of the third switch unit according to the received working time, that is, when the working time of the light-emitting module exceeds the first When the operating time threshold is reached, the third switch unit additionally provides current to the first light emitting unit and the second light emitting unit, so as to compensate for the decrease in the instantaneous luminous brightness of the light emitting device caused by the same driving current caused by the increase in the working time of the light emitting device.

A light emitting module driving method 1000 according to a fourth embodiment of the present invention is described with reference to FIG. 1 , FIG. 2 and FIG. 10 .

In step S1010, the working time of the light emitting module is recorded by the working time monitoring unit.

In step S1020, based on the second control information table, the control unit outputs a switch control signal according to the received working time.

In step S1030, the control terminal of the third switch unit receives the switch control signal, and when the switch control signal is at an effective control level, the third switch unit turns on the power between the first terminal and the second terminal. connection and electrical connection between its third and fourth terminals, and the resistance present between its first and second terminals is equal to the resistance present between its third and fourth terminals.

In step S1040, based on the first control information table, the control unit adjusts the duration of the effective control levels of the first PWM control signal and the second PWM control signal according to the received working time. The first control information table stores the corresponding relationship between the working time and the duration of the effective control levels of the first and second PWM control signals.

In step S1050, the control terminal of the first switch unit receives the first PWM control signal, and controls the first light emitting unit to emit light when the first PWM control signal is at an effective control level.

In step S1060, the control terminal of the second switch unit receives the second PWM control signal, and controls the second light emitting unit to emit light when the second PWM control signal is at an effective control level.

According to the driving method of the fourth embodiment of the present invention, on the one hand, by controlling the first end and the second end of the third switch unit to be turned on and the third end and the fourth end of the third switch unit to be turned on according to the received working time terminal, that is, when the working time of the light-emitting module exceeds the first working time threshold, the third switch unit additionally provides current to the first light-emitting unit and the second light-emitting unit; on the other hand, by adjusting according to the received working time The duration of the effective control levels of the first PWM control signal and the second PWM control signal, that is, as the working time increases, the effective control levels of the first PWM control signal and the second PWM control signal increase according to a predetermined relationship The flat duration can better compensate for the reduction of the luminous brightness of the light emitting device caused by the same driving current caused by the increase of the working time of the light emitting device.

The light emitting module and the control method thereof according to the embodiments of the present invention have been described above with reference to the accompanying drawings. Those skilled in the art should understand that the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention, and the modifications should also be included within the scope of the present invention. The scope of the invention should be defined by the appended claims and their equivalents.

Claims (14)

1. a light emitting module, comprising:

Power supply, for providing supply voltage;

First luminous component, it comprises the first resistance unit, the first switch element and the first luminescence unit that are connected in series, and the first end of this first luminous component is connected with described power supply, the second end of this first luminous component and common electrical press bond; And

Second luminous component, it comprises the second resistance unit, second switch unit and the second luminescence unit that are connected in series, and the first end of this second luminous component is connected with described power supply, the second end of this second luminous component and described common electrical press bond,

Wherein, the control end of the first switch element receives the first pwm control signal, and control the first luminescence unit when described first pwm control signal is in effective control level luminous,

The control end of second switch unit receives the second pwm control signal, and control the second luminescence unit when described second pwm control signal is in effective control level luminous, and

Under the control of described first pwm control signal and the second pwm control signal, described first luminescence unit and described second luminescence unit are alternately luminous.

2. light emitting module as claimed in claim 1, wherein,

The resistance of the first resistance unit is identical with the resistance of the second resistance unit,

Described first pwm control signal is identical with the cycle of the second pwm control signal, and described first pwm control signal is identical with the duration of effective control level of the second pwm control signal.

3. light emitting module as claimed in claim 1, wherein, described first pwm control signal and the second pwm control signal phase 180 °, and the duration of effective control level of described first pwm control signal and the second pwm control signal be all less than the half in the cycle of described first pwm control signal and the second pwm control signal.

4. light emitting module as claimed in claim 1, also comprises:

Working time monitoring unit, for recording the working time of described light emitting module; And

Control module, for receiving the working time that described working time monitoring unit records, and based on the first control information table, adjust the duration of effective control level of described first pwm control signal and the second pwm control signal according to the received working time

Wherein, described first control information table stores the corresponding relation of the duration of effective control level of working time and described first and second pwm control signals.

5. light emitting module as claimed in claim 1, also comprises:

Working time monitoring unit, for recording the working time of described light emitting module;

Control module, for receiving the working time that described working time monitoring unit records, and based on the second control information table, according to received working time output switch control signal; And

Described 3rd switch element, its first end and the second end are connected with the first end of described first resistance unit and the second end respectively, its the 3rd end and the 4th end are connected with the first end of described second resistance unit and the second end respectively, and its control end receives described switch controlling signal

Wherein, when described switch controlling signal is in effective control level, described 3rd switch element connects the electrical connection between its first end and the second end and the electrical connection between its 3rd end and the 4th end, and the resistance existed between its first end and the second end equals the resistance that exists between its 3rd end and the 4th end.

6. light emitting module as claimed in claim 5, wherein,

Wherein, described control module, also based on the first control information table, adjusts the duration of effective control level of described first pwm control signal and the second pwm control signal according to the received working time,

Wherein, described first control information table stores the corresponding relation of the duration of effective control level of working time and described first and second pwm control signals.

7. light emitting module as claimed in claim 5, wherein, described second control information table comprises the first working time threshold value, when the working time that described working time monitoring unit records is greater than described first working time threshold value, the switch controlling signal that described control module exports is in effective control level.

8. light emitting module as claimed in claim 5, wherein, described second control information table comprises the first working time threshold value and the second working time threshold value, the switch controlling signal that described control module exports comprises the first switch controlling signal and second switch control signal, the control end of described 3rd switch element comprises the first control end for receiving described first control signal and the second control end for receiving described second control signal

When the working time that described working time monitoring unit records is greater than described first working time threshold value and is less than described second working time threshold value, described first control signal is in effective control level, described second control signal is in invalid control level, between the first end and the second end of described 3rd switch element, there is the first resistance, between the 3rd end and the 4th end of described 3rd switch element, there is the first resistance;

When the working time that described working time monitoring unit records is greater than described second working time threshold value, described second control signal is in effective control level, the second resistance is there is between the first end and the second end of described 3rd switch element, between the 3rd end and the 4th end of described 3rd switch element, there is the second resistance, and the first resistance is greater than the second resistance.

9. the control method of a light emitting module, described light emitting module comprises power supply, the first luminous component and the second luminous component, described first luminous component comprises the first resistance unit, the first switch element and the first luminescence unit that are connected in series, described second luminous component comprises the second resistance unit, second switch unit and the second luminescence unit that are connected in series, described first luminous component be all connected with described power supply with the first end of the second luminous component and its second end all with common electrical press bond, described control method comprises:

The control end of the first switch element receives the first pwm control signal, and control the first luminescence unit when described first pwm control signal is in effective control level luminous,

The control end of second switch unit receives the second pwm control signal, and control the second luminescence unit when described second pwm control signal is in effective control level luminous,

Wherein, under the control of described first pwm control signal and the second pwm control signal, described first luminescence unit and described second luminescence unit are alternately luminous.

10. control method as claimed in claim 9, wherein, the resistance of the first resistance unit is identical with the resistance of the second resistance unit,

Described first pwm control signal is identical with the cycle of the second pwm control signal, described first pwm control signal and the second pwm control signal phase 180 °,

Described first pwm control signal is identical with the duration of effective control level of the second pwm control signal, and is all less than the half in the cycle of described first pwm control signal and the second pwm control signal.

11. control methods as claimed in claim 9, also comprise:

Record the working time of described light emitting module; And

Based on the first control information table, adjust the duration of effective control level of described first pwm control signal and the second pwm control signal according to the received working time,

Wherein, described first control information table stores the corresponding relation of the duration of effective control level of working time and described first and second pwm control signals.

12. control methods as claimed in claim 9, wherein, described light emitting module also comprises the 3rd switch element, its first end is connected with the first end of described first resistance unit, its second end is connected with the second end of described first resistance unit, its the 3rd end is connected with the first end of described second resistance unit, and its 4th end is connected with the second end of described second resistance unit

Described control method also comprises:

Record the working time of described light emitting module;

Based on the second control information table, according to received working time output switch control signal;

And

The control end of described 3rd switch element receives described switch controlling signal, when described switch controlling signal is in effective control level, described 3rd switch element connects the electrical connection between its first end and the second end and the electrical connection between its 3rd end and the 4th end, and the resistance existed between its first end and the second end equals the resistance that exists between its 3rd end and the 4th end.

13. control methods as claimed in claim 12, also comprise:

Based on the first control information table, adjust the duration of effective control level of described first pwm control signal and the second pwm control signal according to the received working time,

Wherein, described first control information table stores the corresponding relation of the duration of effective control level of working time and described first and second pwm control signals.

14. control methods as claimed in claim 12, wherein, described second control information table comprises the first working time threshold value, when the working time that described working time monitoring unit records is greater than described first working time threshold value, the switch controlling signal that described control module exports is in effective control level.