CN103974492B - Light emitting device and control method thereof - Google Patents

Abstract

The invention discloses a light-emitting device and a control method thereof, comprising the following steps: operating a light emitting module of the light emitting device, wherein the light emitting module comprises a plurality of light emitting unit strings, each light emitting unit string comprises a plurality of light emitting units connected in series, and one end of each light emitting unit string receives a direct current voltage together; capturing the voltage values of the multiple current control units, and further judging whether the light emitting units of the light emitting unit strings are in fault, wherein the current control units are connected with at least one of the light emitting unit strings in series; and when the light emitting unit of a specific string of the light emitting unit strings has a fault and the fault number x is greater than or equal to the critical fault number p, short-circuiting the fault light emitting unit in the specific string and short-circuiting (x-p +1) light emitting units in each light emitting unit string outside the specific string to reduce the direct current voltage received by each light emitting unit.

Description

Light emitting device and control method thereof

technical field

The present disclosure relates to a lighting module control technology, and in particular to a lighting device and method.

Background technique

Whether it is a backlight source for a display panel or a light source for lighting, solid-state light-emitting devices such as light-emitting diodes (light emitting diodes; LEDs) have gradually become mainstream technologies. In a backlight such as a display panel, the light-emitting elements are usually designed in the form of a module to provide a uniform light source for the display panel, wherein the above-mentioned module includes light-emitting elements connected in series. However, in the above-mentioned modules, it is unavoidable that the light-emitting element fails. When one of the light-emitting elements in series fails, the original voltage drop of the failed light-emitting element will be transferred to other elements in the same series. Therefore, when the number of faults increases, the voltage drop of the transfer increases, which will easily cause damage to other components.

In order to avoid the occurrence of the above situation, the conventional method is to turn off the whole string of light-emitting elements when the number of failures of the light-emitting elements in a string reaches a certain amount. However, turning off the whole string of light-emitting elements for possibly a small number of faulty light-emitting elements will greatly reduce the brightness of the light source, which is not conducive to its operating efficiency.

Therefore, how to design a new light-emitting device and method to have a flexible adjustment mechanism when the light-emitting element fails to avoid the disadvantage of greatly reducing the brightness of the light source is an urgent problem to be solved in the industry.

Contents of the invention

The object of the present invention is to provide a light emitting device and a control method thereof to solve at least one of the above problems and/or other problems.

Therefore, one mode of the present disclosure is to provide a light emitting device, including: a light emitting module, a plurality of current control units, and a control module. The light emitting module includes a plurality of light emitting unit strings, and each light emitting unit string includes a plurality of light emitting units connected in series, wherein one end of each light emitting unit string receives a DC voltage together. Each current control unit is connected in series with at least one of the light emitting unit strings to control the current of each light emitting unit string. The control module captures the cross-voltage value of each current control unit, and further judges whether the light-emitting units of each light-emitting unit string fail; and when the light-emitting unit of a specific string of light-emitting unit strings fails and the number of failures x is greater than or equal to the critical number of failures p , the control module short-circuits the faulty light-emitting units in a specific string and short-circuits (x-p+1) light-emitting units in each light-emitting unit string outside the specific string, so as to reduce the DC voltage received by each light-emitting unit string to reduce the current Efficacy of the power consumption of the control unit.

According to an embodiment of the present disclosure, the number m of the light emitting unit strings is smaller than the number n of light emitting units included in each light emitting unit string. When the control module judges that the number (m-1)*(x-p+1) of the short-circuited light-emitting units of each light-emitting unit string outside the specific string is greater than or equal to the number (n-x) of the non-short-circuited light-emitting units in the specific string, The control module turns off a particular string.

According to another embodiment of the present disclosure, each light emitting unit further includes a light emitting element and a parallel switch, and the control module controls the parallel switch to conduct to short-circuit the corresponding light emitting element.

According to yet another embodiment of the disclosure, the control module stores a short-circuited light-emitting unit comparison table to record at least one short-circuited light-emitting unit in each light-emitting unit string and whether the short-circuited light-emitting unit is faulty. Wherein the control module judges whether to short-circuit a normal operator of the light-emitting units in the specific string when short-circuiting the specific string, so as to restore the normal operator to the path when the short-circuit is performed to the normal operator. The control module further judges whether the specific string of light-emitting units has at least one short-circuited normal light-emitting unit according to the short-circuited light-emitting unit comparison table, so as to restore the short-circuited normal light-emitting unit to the path when the number k of the short-circuited normal light-emitting units is less than or equal to x , and when k is greater than x, x short-circuited normal light-emitting units are restored to paths. The control module sequentially short-circuits the light-emitting units of the specific string and judges whether to short-circuit the normal light-emitting units according to the cross-voltage value of the current control unit.

According to still another embodiment of the present disclosure, when the control module short-circuits the light-emitting unit strings outside the specific string, it judges whether the light-emitting units of the light-emitting unit strings outside the specific string have short-circuited light-emitting units according to the short-circuited light-emitting unit comparison table. unit, when the light-emitting unit has a short-circuited light-emitting unit and the number q of the short-circuited light-emitting unit is greater than or equal to (x-p+1), the control module does not short-circuit, and when the number q of the short-circuited light-emitting unit of the light-emitting unit is less than (x-p+1), p+1), the control module short-circuits (x-p+1-q) non-short-circuited light-emitting units.

According to a further embodiment of the present disclosure, when y light-emitting unit strings fail and the number of failures is z, and ((m-1)*(x-p+1)-z)≧((n-x )*y+(p-1)*(y-1)), the control module turns off y light-emitting unit strings.

Another aspect of the present disclosure is to provide a method for controlling a light emitting device, including: operating a light emitting module of the light emitting device, wherein the light emitting module includes a plurality of light emitting unit strings, and each light emitting unit string includes a plurality of light emitting units connected in series, One end of each light-emitting unit string receives a DC voltage; the respective cross-voltage values of multiple current control units are captured to further determine whether the light-emitting unit of each light-emitting unit string is faulty, wherein each current control unit is connected in series with one of the light-emitting unit strings ; and when the light-emitting units of the specific string of the light-emitting unit strings fail and the fault number x is greater than or equal to the critical fault number p, short-circuit the faulty light-emitting units in the specific string and make each light-emitting unit string outside the specific string (x -p+1) light-emitting units are short-circuited to lower the DC voltage received by each light-emitting unit string.

According to an embodiment of the disclosure, the number of light emitting unit strings is less than the number of light emitting units included in each light emitting unit string. The light emitting device control method further includes determining that the number (m-1)*(x-p+1) of short-circuited light-emitting units in each light-emitting unit string outside the specific string is greater than or equal to the number of non-short-circuited light-emitting units in the specific string ( n-x), directly close the specific string.

According to another embodiment of the present disclosure, the step of short-circuiting a specific string further includes judging whether to short-circuit a normal operator of the light-emitting units in the specific string, so as to restore the normal operation when the short-circuit is performed on a normal operator. The operator is the access. The light emitting device control method further includes judging whether the specific string of light emitting units has at least one short-circuited normal light-emitting unit, so that the short-circuited normal light-emitting unit is restored to a path when the number k of the short-circuited normal light-emitting units is less than or equal to x, and at k When it is greater than x, x short-circuited normal light-emitting units are restored to paths.

According to another embodiment of the present disclosure, the step of short-circuiting a specific string further includes sequentially short-circuiting the light-emitting units of the specific string and judging whether to short-circuit the normal light-emitting units according to the cross-voltage value of the current control unit. short circuit.

According to still another embodiment of the present disclosure, the step of short-circuiting the light-emitting unit strings outside the specific string further includes judging whether the light-emitting units of the light-emitting unit strings outside the specific string have short-circuited light-emitting units, and emit light when the short-circuited The number q of units is greater than or equal to (x-p+1), no short circuit is performed, when the number q of short-circuited light-emitting units is less than (x-p+1), make (x-p+1-q) non-short-circuited The light-emitting unit is short-circuited.

According to a further embodiment of the present disclosure, the control method of the light emitting device further includes when y light emitting unit strings fail, the number of faults in each of the y light emitting unit strings is z, and ((m-1) When *(x-p+1)-z)≧((n-x)*y+(p-1)*(y-1)), y light-emitting unit strings are turned off.

The advantage of applying the present disclosure is that by short-circuiting the failed light-emitting units in a specific string and short-circuiting (x-p+1) light-emitting units in each light-emitting unit string outside the specific string, it is possible to avoid damage caused when the entire light-emitting unit string is directly turned off. The disadvantage that the brightness may be greatly reduced can easily achieve the above-mentioned purpose.

Description of drawings

In order to make the above and other objects, features, advantages and embodiments of the present disclosure more comprehensible, the accompanying drawings are described as follows:

FIG. 1A is a circuit diagram of a light emitting device in an embodiment of the present disclosure;

FIG. 1B is a more detailed circuit diagram of a light emitting device in an embodiment of the present disclosure;

FIG. 2 is a circuit diagram of a fault condition in a light-emitting unit string of a light-emitting module in an embodiment of the present disclosure;

FIG. 3 is a circuit diagram of a failure situation of two light-emitting unit strings in a light-emitting module in an embodiment of the present disclosure; and

FIG. 4 is a flow chart of a method for controlling a light emitting device in an embodiment of the present disclosure.

Wherein, the reference signs are explained as follows:

1: Lighting device 10: Lighting module

100: light emitting unit 102: light emitting element

104: Parallel switch 12: Control module

14: dimming control bus 140: current control unit

16: Power module 200: Fault light emitting unit

210: Short-circuit light-emitting unit 400: Light-emitting device control method

401-408: Steps

detailed description

Please refer to Figure 1A. FIG. 1A is a circuit diagram of a light emitting device 1 in an embodiment of the present disclosure. The light emitting device 1 includes: a light emitting module 10 , a control module 12 and a dimming control bus 14 .

The light-emitting module 10 includes a plurality of strings of light-emitting units, which are represented by the first string, the second string, . . . , the m-th string in FIG. 1A . Each light emitting unit string includes a plurality of light emitting units 100 connected in series.

In this embodiment, the light-emitting module 10 includes m light-emitting unit strings in total, and each light-emitting unit string has n light-emitting units 100 arranged in an array form of m rows and n columns. The string of light-emitting units can emit light according to the current and produce a uniform light source. In this embodiment, the number m of the light emitting unit strings is smaller than the number n of the light emitting units 100 included in each light emitting unit string. The dimming control bus 14 can be used to control the current of each light-emitting unit string, so that the light-emitting performance of the light-emitting unit string can be stabilized. In this embodiment, the light emitting device 1 further includes a power module 16 for providing power to the light emitting module 10 to make the light emitting module 10 emit light. Wherein, one end of each light emitting unit string in the light emitting module 10 is commonly connected to the power module 16 .

Please refer to Figure 1B. FIG. 1B is a more detailed circuit diagram of the light emitting device 1 in an embodiment of the present disclosure. In this embodiment, the dimming control bus 14 includes several current control units 140 . Each current control unit 140 is connected in series with the corresponding light emitting unit 100 in the light emitting unit string to control the current flowing through the light emitting unit string. In this embodiment, the current control unit 140 can control the current of the light-emitting unit string to a constant value, so that the light-emitting performance of the light-emitting unit string can be stabilized.

One end of the light emitting unit string receives the DC voltage Vdc in common, and the other end is connected to the ground terminal GND through the current control unit 140 . Wherein, the DC voltage Vdc can be provided by the power module 16 in FIG. 1A . Each light emitting unit 100 in the light emitting unit string includes a light emitting element 102 and a parallel switch 104 . The light emitting element 102 may be a solid state light emitting element. For example, semiconductor light emitting diodes (light emitting diodes; LEDs) and organic light emitting diodes (organic LEDs; OLEDs) are solid state light emitting devices. In different embodiments, the light emitting element 102 can be realized by using different solid state light emitting elements. The parallel switch 104 is connected in parallel with the light emitting element 102 . When the parallel switch 104 is closed and the light-emitting element 102 is not faulty, the light-emitting element 102 will operate normally; and when the parallel switch 104 is turned on, the light-emitting element 102 will be short-circuited regardless of whether it is in a normal state or a fault state.

In one embodiment, the control module 12 can control the opening and closing of the parallel switch 104 through the dimming control bus 14 . In other embodiments, the parallel switch 104 may also be controlled in other ways.

The light emitting unit 100 and the current control unit 140 operate according to the current corresponding to the DC voltage Vdc, so when the light emitting module 10 operates, both the light emitting unit 100 and the current control unit 140 generate a voltage drop. In FIG. 1B , the voltage drop generated by each light emitting unit 100 is represented by Vy(a,b), where a and b represent the position of the light emitting unit 100 in the array of light emitting modules 10 . For example, the voltage drop generated by the light-emitting unit 100 located in row 1, column 1 (that is, the first chip in the first series) is Vy(1,1), and the light-emitting unit 100 located in row m, column n The resulting pressure drop is Vy(m,n). On the other hand, the voltage drops generated by the current control units 140 corresponding to the first light-emitting unit string to the m-th light-emitting unit string are represented by Vz1˜Vzm respectively.

The control module 12 retrieves the voltage across the current control unit 140 corresponding to each light-emitting unit string, and further determines whether the light-emitting unit 100 of each light-emitting unit string is faulty. It should be noted that the failure of the light emitting unit 100 essentially means that the light emitting element 102 thereof fails to operate. Since each light-emitting unit string operates according to the same DC voltage Vdc, the total voltage drop of each light-emitting unit string is equal. When a light-emitting unit 100 in the light-emitting unit string fails, its original voltage drop will be transferred to the corresponding current control unit 140 because it can no longer operate normally. Therefore, by capturing the voltage across the current control unit 140 (ie, the voltage drop of the current control unit 140 ) and determining whether the voltage across the current control unit 140 increases, the control module 12 can determine whether there is a failure of the light emitting unit 100 .

For example, when the light-emitting unit 100 in the first row and the second column fails, the voltage across the corresponding current control unit 140 will be Vz1+Vy(1,2). If the number x of failures of the light emitting units 100 in the same string is greater than or equal to a critical failure number p, the corresponding current control unit 140 will not be able to withstand the high voltage and be damaged, so that the entire string of light emitting units can no longer operate. In one embodiment, the critical failure number p is 2; that is, when the number of failures of the light emitting units 100 in the same string is greater than or equal to 2, the corresponding current control unit 140 will be damaged.

However, when the number of faults x exceeds the critical number of faults p, the entire string of light-emitting units 100 will be turned off. It is easy to lose the brightness of the entire string of light-emitting units 100 because only one or two faulty light-emitting units 100 will cause the entire light-emitting module 10 to emit light. Efficiency drops drastically. For example, when the number m of light-emitting unit strings in the light-emitting module 10 is 4, and the number n of light-emitting units 100 in each string is 13, if the number x of faults in one string is 2, the string will The brightness of 13 light-emitting units 100 in the overall light-emitting module 10 is reduced due to direct shutdown.

Therefore, in the present invention, when the control module 12 judges that one of the light-emitting unit strings has a fault, and the fault number x is greater than or equal to the critical fault number p, it will short-circuit the faulty light-emitting unit 100 in the string, and The (x-p+1) light-emitting units in each light-emitting unit string outside the string are also short-circuited accordingly.

Please refer to Figure 2. FIG. 2 is a circuit diagram of a fault in the light emitting unit string of the light emitting module 10 in an embodiment of the present disclosure.

For example, when the control module 12 is judging the light-emitting module 10, the first row, the first column and the first row, the second column (that is, those with Vy(1,1) and Vy(1,2) voltage drops) are failures When the light-emitting unit 200 is used, the parallel switch 104 connected in parallel with the light-emitting element 200 will be controlled to short-circuit the failed light-emitting unit 100 . In addition, the control module 12 further short-circuits one (2-2+1=1) light-emitting unit in the light-emitting unit strings from the second row to the m-th row. In this embodiment, the control module 12 short-circuits the light-emitting units 210 in the first column from the second row to the m-th row (that is, those with Vy(2,1) . . . Vy(m,1) voltage drop). It should be noted that the above-mentioned short-circuiting of the light-emitting unit may refer to the control module 12 controlling the internal parallel switch 104 to be turned on so as to short-circuit the light-emitting element 102 .

Therefore, except that two light-emitting units 100 in the first string cannot operate, one light-emitting unit 100 in each other string is short-circuited and does not operate. Since the number of elements that can consume current and cause a voltage drop in each string is reduced, the control module 12 can further adjust the DC voltage Vdc so that the DC voltage Vdc drops without causing damage to the elements in each light-emitting unit string, and still enables each string to emit light. Unit 100 operates normally.

Therefore, if the number m of light-emitting unit strings is 4, and the number n of light-emitting units 100 in each string is 13, for example, when dealing with the failure of light-emitting units 100 in the manner of the present invention, only the first string needs to be turned off. The two light-emitting units and one light-emitting unit in each of the second to fourth strings, a total of five light-emitting units 100, and directly shutting down the entire string of light-emitting units 100 causes 13 (including faulty) light-emitting units 100 to fail to operate In comparison, the problem that the light-emitting efficiency of the light-emitting module 10 decreases when the light-emitting unit 100 fails can be greatly improved.

In the above manner, if the number of damaged light-emitting units 100 in the same string is 3 (x=3) and the number of critical failures is 2 (p=2), the control module 12 short-circuits the three failed light-emitting units In addition, two ((x-p+1)=(3-2+1)=2) in other light-emitting unit strings outside the string are also short-circuited.

However, in one embodiment, when the control module 12 judges that the number x of faults is too large to make it uneconomical to turn off the light emitting units 100 in other strings, the light emitting unit string may be directly turned off. That is, if the number of non-short-circuited light-emitting units 100 in a specific string with faulty light-emitting units is (n-x), the number of light-emitting units 100 that need to be short-circuited under the aforementioned mechanism is (m-1)*(x-p+ 1), when the control module 12 judges (m-1)*(x-p+1)≧(n-x), the control module 12 will close the specific string.

For example, if in an array of 4 rows and 13 columns (m=4; n=13), the number of faults in one string is 4 (x=4) and the number of critical faults is 2 (p=2), then the The number of short-circuited light emitting units 100 is equivalent to (n−x)=(13−4)=9 pieces. If the above mechanism is used for adjustment, then a total of (m-1)*(x-p+1)=(3)*(4-2+1)=9 pieces need to be closed. Therefore, the above mechanism is not more advantageous than directly shutting down the specific string, and at this time the control module 12 can directly shut down the specific string.

If in the same array, the number of failures in one string is 5 (x=5), the number of unshort-circuited light-emitting units 100 is equivalent to (n-x)=(13-5)=8. However, if the above mechanism is used for adjustment, a total of (m-1)*(x-p+1)=(3)*(5-2+1)=12 pieces needs to be closed. The control module 12 can determine that the way to close the specific string is more efficient and close the specific string.

Please refer to Figure 3. FIG. 3 is a schematic circuit diagram of a failure situation of two light emitting unit strings in the light emitting module 10 in an embodiment of the present disclosure.

In this embodiment, the light emitting module 10 is an array of 5 rows and 13 columns (m=5; n=13), and the number of critical failures is 2 (p=2). The two light-emitting unit strings in the light-emitting module 10, such as the first string and the fifth string shown in FIG. Unit 200. If controlled in such a way that the entire string of lighting units is turned off, up to 26 lighting units 100 would have to be short-circuited (5 originally failed and 21 additionally turned off). However, in the manner of the present invention, only 11 light-emitting units (5 faulty light-emitting units 200 and 6 additionally turned off light-emitting units 210 ) need to be short-circuited.

In one embodiment, if y light-emitting unit strings fail at the same time, and the number of failures is z, the control module 12 can further determine whether the following formula holds:

((m-1)*(x-p+1)-z)≧((n-x)*y+(p-1)*(y-1))

If the above formula is established, the control module 12 will directly turn off the string of light emitting units. If not, the control module 12 only needs to short-circuit (x−p+1) light emitting units 100 in other light emitting unit strings.

The mechanism of the short circuit of the light emitting unit 100 by the control module 12 will be described in more detail below.

In one embodiment, the control module 12 stores a short-circuited light-emitting unit comparison table (not shown) to record the short-circuited light-emitting unit 100 in each light-emitting unit string and whether the short-circuited light-emitting unit 100 is faulty. Since the control module 12 judges whether there is a failure of the light emitting unit 100 according to the voltage across the current control unit 140 corresponding to each light emitting unit string, the control module 12 can only judge the occurrence of the failure, but cannot know which one is the failure. pieces. Therefore, when performing the short-circuit operation, the light-emitting units 100 in the string will be short-circuited one by one, and check whether the cross-voltage value of the current control unit 140 rises again to determine whether the light-emitting units 100 in normal operation are turned off.

When the normally operating light-emitting unit 100 is turned off, its original voltage drop will be transferred to the current control unit 140 to increase the voltage across the current control unit 140 . Therefore, the control module 12 will turn on the parallel switch 104 of the light-emitting unit 100 again, so that the light-emitting unit 100 will return to the path, and the light-emitting element 102 can continue to operate normally. When the control module 12 judges that the cross-voltage value of the current control unit 140 has not increased, it means that the short-circuited light-emitting unit 100 is a faulty light-emitting unit 200 , and records the short-circuit result in the short-circuited light-emitting unit comparison table.

In one embodiment, the control module 12 further judges according to the short-circuited light-emitting unit comparison table whether a light-emitting unit 100 that can operate normally has been short-circuited in a specific string. When the specific string of light emitting units 100 fails, the control module 12 further determines whether the number k of these “short-circuited but normal light emitting units” is less than or equal to the number x of failed light emitting units 100 .

When k is less than or equal to x, the control module 12 will short-circuit the faulty light-emitting units 200 and restore the paths of these short-circuited and non-faulty light-emitting units. When k is greater than x, the control module 12 will short-circuit the faulty light-emitting units 200, and restore x short-circuited but non-faulty light-emitting units to the path. The control module 12 will further modify the comparison table of the short-circuited light-emitting units to store the new short-circuit result therein.

For other light-emitting unit strings other than the specific string, the control module 12 can also perform a short-circuit mechanism according to the short-circuited light-emitting unit comparison table.

In one embodiment, when short-circuiting the light-emitting unit strings outside the specific string, the control module 12 determines whether the light-emitting unit 100 of each light-emitting unit string has a short-circuited light-emitting unit 100 according to the short-circuited light-emitting unit comparison table. When there are short-circuited light-emitting units 100 and the number q of these short-circuited light-emitting units 100 is greater than or equal to (x-p+1), the control module 12 does not short-circuit, and when the number q of the short-circuited light-emitting units of the light-emitting units is less than ( When x-p+1), the control module 12 short-circuits (x-p+1-q) non-short-circuited light-emitting units.

For example, in an array of 4 rows and 13 columns (m=4; n=13), the number of failures of the light-emitting units 100 in the first string is 3 (x=3) and the number of critical failures is 2 (p= 2), then there are two light-emitting units 100 to be short-circuited in the second string to the fourth string ((x-p+1)=(3-2+1)=2). If more than two light-emitting units 100 in one of the second to fourth strings have been short-circuited at this time, the control module 12 does not need to short-circuit the light-emitting units 100 of the string. And if one of the other light-emitting unit strings outside the specific string has a light-emitting unit 100 that has been short-circuited at this time, the control module 12 only needs to control one of the remaining non-short-circuited light-emitting units 10 ((x−p +1-q)=(3-2+1-1)=1) for short circuit.

Therefore, after being assisted by the above mechanism, more flexible control can be performed on the light emitting module 10, and the brightness of the light emitting module 10 can be maintained as much as possible while avoiding element damage.

It should be noted that in the above-mentioned embodiments, one current control unit corresponds to one light-emitting unit string as an example for illustration. In other embodiments, one current control unit may correspond to more than two parallel-connected light-emitting unit strings, and the control module controls and adjusts the switches of the light-emitting units in the above-mentioned manner.

Please refer to Figure 4. FIG. 4 is a flow chart of a method 400 for controlling a lighting device in an embodiment of the present disclosure. The lighting device control method 400 can be applied to the lighting device 1 shown in FIG. 1A and FIG. 1B , but is not limited thereto. The light emitting device control method 400 includes the following steps (it should be understood that the steps mentioned in this embodiment, unless the order is specifically stated, can be adjusted according to actual needs, and can even be executed simultaneously or partially simultaneously ).

In step 401 , the light emitting module 1 having an array of m rows and n columns of light emitting units 100 is operated.

In step 402, the control module 12 retrieves the voltage across the current control unit 140 corresponding to each light emitting unit string, and further determines in step 403 whether the light emitting unit 100 of each light emitting unit string is faulty. When the light-emitting units of the specific string are not faulty, the process returns to step 402 .

When the light-emitting units of the specific string fail, the control module 12 determines whether the failure number x is greater than or equal to the critical failure number p in step 404 . When the fault number is less than the critical fault number p, the control module 12 will not act, and the process will go back to step 402 .

When the control module 12 judges in step 403 that the fault number x is greater than or equal to the critical fault number p, the control module 12 further judges in step 405 whether the number of short-circuited light-emitting units in each light-emitting unit string outside the specific string with faulty light-emitting units is greater than Or equal to the number of non-short-circuited light-emitting units 100 in a particular string. That is, to judge whether the following formula holds true:

(m-1)*(x-p+1)≧(n-x)

If yes, the control module 12 directly shuts down the specific string in step 406 .

When not established, the control module 12 short-circuits the faulty light-emitting unit 200 in the specific string in step 407 and short-circuits the (x-p+1) light-emitting units 210 in each light-emitting unit string outside the specific string, and in step 408 downgrades DC voltage Vdc received by each light emitting unit string.

Although the present disclosure has been disclosed above in terms of implementation, it is not intended to limit the present disclosure. Any person skilled in the art may make various modifications and modifications without departing from the spirit and scope of the present disclosure. Therefore, the scope of protection of the disclosure should be defined by the scope of the appended patent claims.

Claims (18)

1. A lighting device, comprising: A light-emitting module, including a plurality of light-emitting unit strings, each of which includes a plurality of light-emitting units connected in series, wherein one end of each of the light-emitting unit strings receives a DC voltage; A dimming control bus, including a plurality of current control units, each connected in series with at least one of the light emitting unit strings, so as to control a current of each of the light emitting unit strings; a control module, used to capture a voltage value across each of the current control units, and further determine whether the light-emitting unit of each of the light-emitting unit strings is faulty; and When the light-emitting unit of a specific string of the light-emitting unit string fails and a fault number x is greater than or equal to a critical fault number p, the control module short-circuits the faulty light-emitting unit in the specific string and makes the specific string (x-p+1) of the light-emitting units in each of the light-emitting unit strings are short-circuited to lower the DC voltage received by each of the light-emitting unit strings. 2. The light-emitting device according to claim 1, wherein the number m of the light-emitting unit strings is smaller than the number n of the light-emitting units contained in each light-emitting unit string. 3. The light-emitting device according to claim 2, wherein when the control module judges that the number (m-1)*(x-p+1) of the light-emitting units short-circuited by each of the light-emitting unit strings outside the specific string is greater than or equal to the number (n-x) of the light-emitting units in the specific string that are not short-circuited, the control module turns off the specific string. 4 . The light emitting device according to claim 1 , wherein each light emitting unit further comprises a light emitting element and a parallel switch, and the control module short-circuits the corresponding light emitting element by controlling the parallel switch to conduct. 5. The lighting device as claimed in claim 1, wherein the control module stores a short-circuited light-emitting unit comparison table to record at least one short-circuited light-emitting unit in each of the light-emitting unit strings and whether the short-circuited light-emitting unit is faulty. 6. The lighting device according to claim 5, wherein the control module judges whether to short-circuit one of the light-emitting units in the specific string when the specific string is short-circuited, so as to short-circuit the normal operation of the string. In case of a short circuit, the normal operation is restored to the path. 7. The light-emitting device according to claim 6, wherein the control module further judges whether the light-emitting unit in the specific string has at least one short-circuited normal light-emitting unit according to the short-circuited light-emitting unit comparison table, so as to emit light in the short-circuited normal light-emitting unit When the number k of units is less than or equal to the fault number x, the short-circuited normal light-emitting unit is restored to the path, and when k is greater than x, the x short-circuited normal light-emitting units are restored to the path. 8. The light-emitting device according to claim 6, wherein the control module short-circuits one of the light-emitting units of the specific string sequentially and judges whether to short-circuit the short-circuited normal light-emitting unit according to the cross-voltage value of the current control unit . 9. The lighting device according to claim 5, wherein the control module judges each of the light-emitting unit strings outside the specific string according to the short-circuited light-emitting unit comparison table when short-circuiting each of the light-emitting unit strings outside the specific string Whether there is the short-circuited light-emitting unit, when the number q of the short-circuited light-emitting units is greater than or equal to (x-p+1), the control module does not short-circuit, and when the number q of the short-circuited light-emitting units of the light-emitting unit is less than ( x-p+1), the control module short-circuits (x-p+1-q) non-short-circuited light-emitting units. 10. The light-emitting device according to claim 2, wherein when y light-emitting unit strings fail and the number of failures is z, and ((m-1)*(x-p+1)-z)≧ When ((n-x)*y+(p-1)*(y-1)), the control module turns off y light-emitting unit strings. 11. A method for controlling a lighting device, comprising: Make a light-emitting module of a light-emitting device operate, wherein the light-emitting module includes a plurality of light-emitting unit strings, and each of the light-emitting unit strings includes a plurality of light-emitting units connected in series, wherein one end of each of the light-emitting unit strings receives a DC voltage; Retrieving a cross-voltage value of each of the plurality of current control units, and further judging whether the light-emitting unit of each of the light-emitting unit strings is faulty, wherein each of the current control units is connected in series with one of the light-emitting unit strings; and When the light-emitting units of a specific string of the light-emitting unit strings fail and a fault number x is greater than or equal to a critical fault number p, short-circuit the faulty light-emitting units in the specific string and make each of the faults outside the specific string The (x−p+1) light emitting units in the light emitting unit strings are short-circuited to lower the DC voltage received by each of the light emitting unit strings. 12. The light emitting device control method according to claim 11, wherein the number m of the light emitting unit strings is smaller than the number n of the light emitting units included in each of the light emitting unit strings. 13. The method for controlling a light-emitting device according to claim 12, further comprising determining the number (m-1)*(x-p+1) of the light-emitting units that are short-circuited in each of the light-emitting unit strings out of the specific string When greater than or equal to the number (n-x) of the light-emitting units in the specific string that are not short-circuited, the specific string is turned off. 14. The light emitting device control method as claimed in claim 11, wherein the step of short-circuiting the specific string further comprises judging whether a normal operation of the light-emitting units in the specific string is short-circuited, so as to short-circuit the normal operation of the specific string. When the operator is short-circuited, the normal operator is restored to the path. 15. The method for controlling a light-emitting device according to claim 14, further comprising judging whether the light-emitting unit of the specific string has at least one short-circuited normal light-emitting unit, so that the number k of the short-circuited normal light-emitting units is less than or equal to x When k is greater than x, the short-circuited normal light-emitting unit is restored to the path, and when k is greater than x, x of the short-circuited normal light-emitting units are restored to the path. 16. The light-emitting device control method according to claim 14, wherein the step of short-circuiting the specific string further comprises sequentially short-circuiting one of the light-emitting units of the specific string and controlling the unit according to the cross-voltage value of the current It is judged whether to short-circuit the normal light-emitting unit that has been short-circuited. 17. The light-emitting device control method according to claim 11, wherein the step of short-circuiting each of the light-emitting unit strings outside the specific string further includes judging whether the light-emitting units of each of the light-emitting unit strings outside the specific string have The short-circuited light-emitting unit, when the number q of the short-circuited light-emitting unit is greater than or equal to (x-p+1), no short-circuit is performed, and when the number q of the short-circuited light-emitting unit is less than (x-p+1), make (x -p+1-q) non-short-circuited light-emitting units are short-circuited. 18. The light emitting device control method according to claim 12, further comprising when y light emitting unit strings fail, the number of faults in each of the y light emitting unit strings is z, and ((m-1 )*(x-p+1)-z)≧((n-x)*y+(p-1)*(y-1)), turn off y light-emitting unit strings.