The present invention relates to driver devices for Light Emitting Diodes based illumination system. More particular, the present invention relates to a driver device for Light Emitting Diodes based illumination system having short circuit detection and protection mechanism for vehicular applications.
Background of the Invention:
A two-wheeler vehicle such as bike, motorbike, scooter and the like comprises a number of lights such as a position indicating light, left & right winkers at the front, left & right winkers at the rear, a license plate illuminating light (located near a rear license plate), and a tail stop light associated with brakes. In the prior art, said lights incorporated incandescent bulbs.
The automobile industry is evolving and moving towards replacing incandescent bulb with Light Emitting Diodes (hereinafter LED) for the fact that LED has extremely long lifespan and are energy efficient as compared to any other lighting technology. In many cases, an incandescent bulb is replaced by different number(s) of LED. For example, one incandescent bulb may be replaced by one or two or three LED connected in series.
A conventional circuit (100) comprising a plurality of LED clusters for use in a vehicle is shown in Figure 1. The circuit (100) is shown to comprise of a front-left LED winker cluster (102), a front-right LED winker cluster (104), a rear-left LED winker cluster (106), a rear-right LED winker cluster (108), a position LED cluster (110), a license plate illuminating LED cluster (112), and a tail-stop LED cluster (114). It may be noted that the circuit may comprise of additional or lesser number of LED clusters. While the number of LED as contained in each LED cluster may vary, each LED cluster is shown to comprise of plurality of LEDs connected in series. The circuit (100) further comprises a power source (116), which may be a battery or regulator/rectifier device. The circuit (100) further comprises a driver device (118) connected between the power source (116) and the plurality of LED clusters (102, ..., 114) that provides the currents as required by each LED cluster. The driver device (118) comprises a buck converter (120) that receives input voltage from the power source (116) and converts the input voltage to a predetermined driving voltage. The driver device (118) further comprises plurality of current regulators (122i..j) that are connected in parallel to each other and to an output of the buck converter (120). Each of the plurality of current regulator (122i..j) is configured to receive the preconfigured driving voltage and generate preconfigured constant current for supply to the LED cluster connected thereto (the purpose

of providing constant current to the LED cluster is to realize constant luminance from the LED cluster).
The predetermined driving voltage as supplied by the buck converter (120) is generally lesser than the input voltage as received by the buck converter and slightly higher than the output voltage as provided by the current regulators (122i..j). This ensures that the current regulators work properly and at the same time, the voltage difference across the current regulators is less (to minimize power dissipation).
In the circuit of the aforesaid nature, there are two possibilities with regard to failure of the LED (as contained in the LED cluster (102, ..., 114)), namely LED open condition and LED short-circuit condition. In case one or more LED as contained in the LED cluster (102, ..., 114) fails (hereinafter faulty LED cluster) in LED open condition, the faulty LED cluster is automatically disconnected from the current regulator (122).
In case one or more LED as contained in the LED cluster (102, ..., 114) fails in LED short-circuit condition, the faulty LED cluster is not disconnected from the current regulator (122). A faulty LED cluster having one or more LED in LED short-circuit condition may affect other components forming part of the circuit (100) and create the following problems:
1. Output voltage of the current regulator connected to the faulty LED cluster drops, causing an increased voltage difference across said current regulator. As a result, heat dissipation in the current regulator connected to the faulty LED cluster increases and this may lead to eventual failure of said current regulator.
2. As the faulty LED cluster is not disconnected from the output of the current regulator , the failure may not be detected and no appropriate action may be taken. Also, there is a decrease in the light intensity output of the faulty LED cluster, which may affect the visibility. In a worst case scenario, it may lead to violation of regulatory norms, especially norms pertaining to photometry requirements.
Thus, there exists a need to provide a simple and cost effective solution to address aforesaid disadvantage.
Summary of the Invention:
This summary is provided to introduce a selection of concepts in a simplified format that is further described in the detailed description of the invention. This summary is neither

intended to identify key or essential inventive concepts of the invention and nor is it intended for determining the scope of the invention.
Accordingly, the present invention provides a driver device for LED based illumination system forming part of a vehicle. The driver device may be connected between a power source and a plurality of LED clusters as provided in the vehicle. The driver device comprises a buck converter configured to receive input voltage from the power source and generate a preconfigured driving voltage. In an embodiment of the invention, the driver device further comprises a plurality of current control devices adapted to receive the preconfigured driving voltage as produced by the buck converter and generate preconfigured constant driving currents along a plurality of current flow paths that are parallel to each other. To each of the current flow path a LED cluster is connected, with each LED cluster having a plurality of LED. The driver device further comprises plurality of voltage sensors connected to the plurality of the current flow paths such that voltage in each current flow path after the corresponding current control device is detected. The driver device further comprises a control unit adapted to determine "LED cluster having at least one LED short-circuit failure" condition if voltage detected by the voltage sensor connected thereto is equal to or less than a corresponding threshold value i.e. if VOUTy < Uy, wherein VOUTy is the voltage as detected by the voltage sensor, Uy is the threshold value and y has a value in the range of 1 to n.
To further clarify the advantages and features of the present invention, a more particular description of the invention will be rendered by reference to specific embodiments thereof, which is illustrated in the appended drawings. It is appreciated that these drawings depict only typical embodiments of the invention and are therefore not to be considered limiting of its scope. The invention will be described and explained with additional specificity and detail with the accompanying drawings.
Brief Description of the drawings:
These and other features, aspects, and advantages of the present invention will become better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like parts throughout the drawings, wherein:
Figure 1 demonstrates a conventional circuit comprising a plurality of LED clusters for use in a vehicle;

Figure 2 demonstrates a circuit comprising a driver device having short circuit detection
mechanism in accordance with the teachings of the present application connected between a
power source and a plurality of LED clusters as provided in a vehicle;
Figure 3 demonstrates a circuit comprising a driver device having short circuit detection
mechanism in accordance with an example of the present application connected between a
power source and plurality of LED clusters that include Front-Right Winker LED cluster,
Front-Left Winker LED cluster, Rear-Right Winker LED cluster, Rear-Left Winker LED
cluster, Position LED cluster, License Plate Illuminating LED cluster, and Tail-Stop Light
LED cluster as provided in a vehicle;
Figure 4 demonstrates a circuit comprising a driver device having short circuit detection and
protection mechanism in accordance with the teachings of the present application connected
between a power source and a plurality of LED clusters as provided in a vehicle;
Figure 5 demonstrates a circuit comprising a driver device having short circuit detection and
protection mechanism in accordance with an example of the present application connected
between a power source and a plurality of LED clusters that include Front-Right LED Winker
cluster, Front-Left Winker LED cluster, Rear-Right Winker LED cluster, Rear-Left Winker
LED cluster, Position LED cluster, License Plate Illuminating LED cluster, and Tail-Stop
Light LED cluster as provided in a vehicle; and
Figure 6 demonstrates a circuit comprising a driver device having short circuit detection and
protection mechanism and other facilities in accordance with an example of the present
application.
Further, skilled artisans will appreciate that elements in the drawings are illustrated for simplicity and may not have been necessarily been drawn to scale. For example, the flow charts illustrate the method in terms of the most prominent steps involved to help to improve understanding of aspects of the present invention. Furthermore, in terms of the construction of the device, one or more components of the device may have been represented in the drawings by conventional symbols, and the drawings may show only those specific details that are pertinent to understanding the embodiments of the present invention so as not to obscure the drawings with details that will be readily apparent to those of ordinary skill in the art having benefit of the description herein.
DETAILED DESCRIPTION OF FIGURES

For the purpose of promoting an understanding of the principles of the invention, reference will now be made to the embodiment illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended, such alterations and further modifications in the illustrated system, and such further applications of the principles of the invention as illustrated therein being contemplated as would normally occur to one skilled in the art to which the invention relates.
It will be understood by those skilled in the art that the foregoing general description and the following detailed description are explanatory of the invention and are not intended to be restrictive thereof.
Reference throughout this specification to "an aspect", "another aspect" or similar language means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, appearances of the phrase "in an embodiment", "in another embodiment" and similar language throughout this specification may, but do not necessarily, all refer to the same embodiment.
The terms "comprises", "comprising", or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a process or method that comprises a list of steps does not include only those steps but may include other steps not expressly listed or inherent to such process or method. Similarly, one or more devices or sub-systems or elements or structures or components proceeded by "comprises... a" does not, without more constraints, preclude the existence of other devices or other sub-systems or other elements or other structures or other components or additional devices or additional sub-systems or additional elements or additional structures or additional components.
Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skilled in the art to which this invention belongs. The system, methods, and examples provided herein are illustrative only and not intended to be limiting.
Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

Referring to Figure 2, a two-wheeled vehicle may be provided with a circuit (200) that
comprises a power source (202) and a plurality of LED clusters (204i n). The circuit also
comprises a driver device (206) connected between a power source (202) and a plurality of LED clusters (2041....n). It may be noted that the driver device (206) defines plurality of output
current flow paths (212i n) that are parallel to one another to which the plurality of LED
clusters are connected. While in Figure 2, for the sake of simplicity (and not as a limitation), one LED cluster is shown to be connected to a particular output current flow path, it is feasible that in some cases two or more LED clusters are connected to a particular output current flow path and it is also feasible that in some cases two or more output current flow paths are interconnected and then connected to one LED cluster.
The driver device (206) comprises a buck converter (208) configured to receive input voltage from the power source (202) and generate a preconfigured driving voltage. The driver device
(206) further comprises plurality of current control devices (210i n) adapted to receive the
preconfigured driving voltage as produced by the buck converter (208) and generate preconfigured constant driving currents along the plurality of output current flow paths
(212i n). The current control devices (210i n) produce constant driving currents so as to
maintain constant luminance from the LED cluster.
The driver device (206) further comprises plurality of voltage sensors (214i...n) connected to the plurality of output current flow paths (212i....n). Generally speaking, there exists a one-to-one relationship between the number of output current flow paths (212 i....n), the number of
current control devices (210i n), and the number of voltage sensors (214i....n) such that one
output current flow path has one current control device and one voltage sensor connected
thereto. In a preferred embodiment of the invention, the voltage sensor is connected
downstream of the current control device so that voltage in each current flow path after the
corresponding current control device is detected (i.e. VOUTi n is detected).
The driver device (206) further comprises a control unit (216) adapted to determine "LED
cluster having at least one LED short-circuit failure" condition if voltage detected by the
voltage sensor (i.e. VOUTi n) is equal to or less than a corresponding threshold value (i.e.
Ul n)-

In an embodiment of the invention, the driver device (206) further comprises a memory unit
(218) that stores the threshold values (Ui n) for all output current flow paths (212i....n). The
control unit (216) is operably connected to the memory unit (218) and is adapted to retrieve
the threshold values (Ui n) and compare the threshold values with the voltage detected
(VOUTi J by the voltage sensors.
In case one or more LED as contained in a particular LED cluster (2041 n) fails in LED
short-circuit condition, the output voltage of the current control device (210i...n) connected to the faulty LED cluster or in other words, the output voltage of the current flow path having the faulty LED cluster drops, which is sensed by the voltage sensor connected thereto. Thus, the control unit (216) is adapted to determine "LED cluster having at least one LED short-circuit failure" condition if voltage detected by the voltage sensor is equal to or less than a corresponding threshold value.
In simpler words, the control unit (216) is adapted to determine "LED cluster having at least one LED short-circuit failure" condition if: VOUTy < Uy, wherein VOUTy is the voltage as detected by the voltage sensor, Uy is the threshold value and y has a value in the range of 1 to n and corresponds to the output current flow path.
Now referring to Figure 3, a particular example of the driver device as described in Figure 2
is provided. In Figure 3, there is illustrated a block diagram of a circuit (300) comprising a
power source (302). The circuit is shown to comprise of 7 LED clusters namely a Front-Left
Winker LED cluster (3041), Front-Right Winker LED cluster (3042), Rear-Left Winker LED
cluster (3043), Rear-Right Winker LED cluster (3044), Position LED cluster (3045), License
Plate Illuminating LED cluster (304e), and Tail-Stop Light LED cluster (304/) as provided in
a vehicle. The circuit further comprises a driver device (306) having the short circuit
detection mechanism which is connected between the power source (302) and the LED
clusters (3041, , 3047).
The driver device (306) is shown to define 7 output current flow paths (3121, 3122, 3123, 3124, 3125, 3126 and 3127) that are parallel to one another. To the first output current flow path (312i) the Front-Left Winker LED cluster (3041) is connected, to the second output current flow path (3122) the Front-Right Winker LED cluster (3042) is connected, to the third output current flow path (312s) the Rear-Left Winker LED cluster (304s) is connected, to the fourth output current flow path (3124) the Rear-Right Winker LED cluster (3044) is connected, to

the fifth output current flow path (312s) the Position LED cluster (304s) is connected, to the sixth output current flow path (3126) the License Plate Illuminating LED cluster (304e) is connected, and to the seventh output current flow path (3127) the Tail-Stop Light LED cluster (3047) is connected.
The driver device (306) comprises a buck converter (308) configured to receive input voltage from the power source (302) and generate a preconfigured driving voltage. The driver device (306) further comprises a seven current control devices (310i, 3IO2, 3IO3, 3IO4, 310s, 3106, and 3IO7) adapted to receive the preconfigured driving voltage as produced by the buck converter (308) and generate preconfigured constant driving currents along the seven output
current flow paths (3121, , 3127). In particular, to the first output current flow path (312i)
the first current control device (310i) is connected, to the second output current flow path (3122) the second current control device (3IO2) is connected, to the third output current flow path (3123) the third current control device (3IO3) is connected, to the fourth output current flow path (3124) the fourth current control device (3IO4) is connected, to the fifth output current flow path (312s) the fifth current control device (310s) is connected, to the sixth output current flow path (312e) the sixth current control device (310e) is connected, and to the seventh output current flow path (3127) the seventh current control device (3IO7) is connected. Each of the seven current control devices (310i, ...., 3IO7) produces constant
driving currents so as to maintain constant luminance of the 7 LED clusters (304i, , 304/)
connected thereto.
The driver device (306) further comprises seven voltage sensors (314i, ...., 3H7) connected to the seven current flow paths (312i, ..... 3127). In particular, the first voltage sensor (314i) is connected to the first output current flow path (312i) so as to be downstream of the first current control device (310i). Likewise, the second voltage sensor (3142) is connected to the second output current flow path (3122) so as to be downstream of the second current control device (3102), the third voltage sensor (314 3) is connected to the third output current flow path (3123) so as to be downstream of the third current control device (3103), the fourth voltage sensor (3144) is connected to the fourth output current flow path (3124) so as to be downstream of the fourth current control device (3IO4), the fifth voltage sensor (314s) is connected to the fifth output current flow path (312s) so as to be downstream of the fifth current control device (310s), the sixth voltage sensor (314 6) is connected to the sixth output current flow path (312e) so as to be downstream of the sixth current control device (310e),

and the seventh voltage sensor (3147) is connected to the seventh output current flow path (3127) so as to be downstream of the seventh current control device (3107).
In particular, the first voltage sensor (314i) is adapted to sense a first output voltage (VOUTi) in the first output current flow path (312i) downstream of the first current control device (310i). Likewise, second voltage sensor (3142) is adapted to sense a second output voltage (VOUT2) in the second output current flow path (3122) downstream of the second current control device (3IO2). Similarly, the third voltage sensor (3143) is adapted to sense a third output voltage (VOUT3) in the third output current flow path (312s) downstream of the third current control device (3IO3). The fourth voltage sensor (314 4) is likewise adapted to sense a fourth output voltage (VOUT4) in the fourth output current flow path (3124) downstream of the fourth current control device (3IO4). The fifth voltage sensor (314s) is similarly adapted to sense a fifth output voltage (VOUT5) in the fifth output current flow path (312s) downstream of the fifth current control device (310s). The sixth voltage sensor (314 6) is adapted to sense a sixth output voltage (VOUTe) in the sixth output current flow path (312e) downstream of the sixth current control device (310e). Last, but not the least, the seventh voltage sensor (3147) is adapted to sense a seventh output voltage (VOUT7) in the seventh output current flow path (3127) downstream of the seventh current control device (3IO7).
The driver device (306) further comprises a control unit (316). The control unit (316) is operatively coupled to the seven voltage sensors (314i, ...., 3147). The control unit (316) is adapted to receive the first to the seventh output voltages (VOUTi, VOUT2, VOUT3, VOUT4, VOUT5, VOUT6, VOUT7) from the seven voltage sensors (314i, ..... 3147).
The driver device (306) further comprises a memory unit (318) that stores seven threshold values (Ui, U2, U3, U4, U5, U6, and U7) corresponding to each of the first to the seventh output current flow path (312i, ...., 3127). The control unit (316) is coupled to the memory unit (318) and is adapted to retrieve the seven threshold values (Ui, U2, U3, U4, U5, U6, and U7). Furthermore, the control unit (316) is adapted to compare each of the seven output voltages (VOUTi, VOUT2, VOUT3, VOUT4, VOUT5, VOUT6, VOUT7) with its corresponding threshold value (Ui, U2, U3, U4, U5, U6, and U7).
In particular, the control unit (316) compares the first output voltage (VOUTi) with the threshold value corresponding thereto (Ui) and determine "Front-Left Winker LED cluster (3041) having at least one LED short-circuit failure condition" in case the first output voltage

(VOUTi) is equal to or less that the threshold value corresponding thereto (Ui). Likewise, the control unit (316) compares the second output voltage (VOUT2) with the threshold value corresponding thereto (U2) and determine "Front-Right Winker LED cluster (3042) having at least one LED short-circuit failure condition" in case the second output voltage (VOUT2) is equal to or less that the threshold value corresponding thereto (U2).
Likewise, the control unit (316) compares the third output voltage (VOUT3) with the threshold value corresponding thereto (U3) and determine "Rear-Left Winker LED cluster (3043) having at least one LED short-circuit failure condition" in case the third output voltage (VOUT3) is equal to or less that the threshold value corresponding thereto (U3). Similarly, the control unit (316) compares the fourth output voltage (VOUT4) with the threshold value corresponding thereto (U4) and determine "Rear-Right Winker LED cluster (3044) having at least one LED short-circuit failure condition" in case the fourth output voltage (VOUT4) is equal to or less that the threshold value corresponding thereto (U4).
Likewise, the control unit (316) compares the fifth output voltage (VOUT5) with the threshold value corresponding thereto (U5) and determine "Position LED cluster (304s) having at least one LED short-circuit failure condition" in case the fifth output voltage (VOUT5) is equal to or less that the threshold value corresponding thereto (U5). Similarly, the control unit (316) compares the sixth output voltage (VOUTe) with the threshold value corresponding thereto (Ue) and determine "License Plate Illuminating LED cluster (304e) having at least one LED short-circuit failure condition" in case the sixth output voltage (VOUTe) is equal to or less that the threshold value corresponding thereto (Ue). Last, but not the least, the control unit (316) compares the seventh output voltage (VOUT7) with the threshold value corresponding thereto (U7) and determine "Tail Stop Light LED cluster (3047) having at least one LED short-circuit failure condition" in case the seventh output voltage (VOUT7) is equal to or less that the threshold value corresponding thereto (U7).
It may be noted that the threshold values (Ui, U2, U3, U4, U5, U6, and U7) corresponding to each of seven output current flow paths (3121, 3122, 3123, 3124, 312s, 3126, and 3127) can be set by the user. The values can be same or different.
Generally speaking, a particular threshold value is set on the basis of the characteristics of the LED cluster. For instance, if the Front-Left Winker LED cluster (3041) comprises three LED, each of which has a voltage requirement of 2.5 volts, then the voltage requirement of the

Front-Left Winker LED cluster (304i) is said to be equal to 7.5 volts. In this case, the threshold value Ui can be set for example as 7 volts. Thus, when the first output voltage (VOUTi) is less than 7 volts, then it can be said that at least one of the three LED of the Front-Left Winker LED cluster (3041) has failed in short-circuit condition.
In yet another example, if the Position LED cluster (304s) comprises two LED, each having a voltage requirement of 1.8 volts, then the voltage requirement of the Position LED cluster (3045) is said to be equal to 3.6 volts. In this case, the threshold value U5 can be set for example, as 3.2 volts. Thus, when the fifth voltage output (VOUT5) is less than 3.2 volts, then it can be said that at least one of the two LED of the Position LED cluster (304 5) has failed in short-circuit condition.
In yet another example, if the Tail Stop Light LED cluster (304/) comprises five LED, each having a voltage requirement of 1.8 volts, then the voltage requirement of the Tail Stop Light LED cluster (304/) is said to be equal to 9 volts. In this case, the threshold value U7 can be set for example, as 8.5 volts. Thus, when the seventh voltage output (VOUT7) is less than 8.5 volts, then it can be said that at least one of the five LED of the Tail Stop Light LED cluster (3047) has failed in short-circuit condition.
While the driver device in Figures 2 and 3, is shown to include mechanism for detecting short circuit condition in relation to at least one LED contained in the LED cluster, in an embodiment of the invention, the driver device may also be provided with a protection mechanism that protects the driver device in case of a short circuit condition.
Now referring to Figure 4, there is illustrated a circuit (400) comprising a driver device (406) having short circuit detection and protection mechanism in accordance with the teachings of the present application connected between a power source (402) and a plurality of LED clusters (404i....n) as provided in a vehicle. The driver device (406) defines plurality of output
current flow paths (412i n) that are parallel to one another to which the plurality of LED
clusters are connected.
The driver device (406) comprises a buck converter (408) configured to receive input voltage from the power source (402) and generate a preconfigured driving voltage. The driver device
(406) further comprises a plurality of current control devices (410i n) adapted to receive
the preconfigured driving voltage as produced by the buck converter (408) and generate

preconfigured constant driving currents along the plurality of output current flow paths
(412i J. The current control devices (410i n) produce constant driving currents so as to
maintain constant luminance from the LED cluster.
The driver device (406) further comprises plurality of voltage sensors (414i...n) connected to the plurality of the current flow paths (412i....n) such that one output current flow path has one current control device and one voltage sensor connected thereto with the voltage sensor being connected downstream of the current control device so that voltage in each current flow path after the corresponding current control device is detected.
In an embodiment of the invention, the driver device (406) further comprises a memory unit (418) that stores the threshold values for all output current flow paths (4121....n) and a control unit (416) operably connected to the memory unit (418). The control unit (416) is adapted to retrieve the threshold values and compare the threshold values with the voltage detected by the voltage sensors. The control unit (416) is adapted to determine "LED cluster having at least one LED short-circuit failure" condition if voltage detected by the voltage sensor is equal to or less than a corresponding threshold value.
In response to determining "LED cluster having at least one LED short-circuit failure" condition the control unit (416) is adapted to generate a "current control device switch OFF signal".
The driver device (406) further comprises plurality of switching devices (420i n) connected
to the plurality of current control devices (410i n) such that one current control device has
one switching device connected thereto. The plurality of switching devices (420i n) are
connected to the control unit (416) and the control unit (416) is configured to supply the "current control device switch OFF signal" to the switching device. In response to receiving the "current control device switch OFF signal", the switching device is adapted to switch OFF the current control device connected thereto.
Now referring to Figure 5, a particular example of the driver device as described in Figure 4 is provided. In Figure 5, there is illustrated a block diagram of a circuit (500) comprising a power source (502). The circuit is shown to comprise of 7 LED clusters namely a Front-Left Winker LED cluster (5041), Front-Right Winker LED cluster (5042), Rear-Left Winker LED cluster (5043), Rear-Right Winker LED cluster (504^, Position LED cluster (504s), License

Plate Illuminating LED cluster (504e), and Tail-Stop Light LED cluster (504/) as provided in
a vehicle. The circuit further comprises a driver device (506) having the short circuit
detection and protection mechanism which is connected between the power source (502) and
the LED clusters (504i, , 5047).
The driver device (506) is shown to define 7 output current flow paths (512i, 5122, 5123, 5124, 5125, 5126 and 512z) that are parallel to one another. The Front-Left Winker LED cluster (5041) is connected to the first output current flow path (512i), the Front-Right Winker LED cluster (5042) is connected to the second output current flow path (5122), the Rear-Left Winker LED cluster (504s) is connected to the third output current flow path (5123), the Rear-Right Winker LED cluster (5044) is connected to the fourth output current flow path (5124), the Position LED cluster (504s) is connected to the fifth output current flow path (5125), the License Plate Illuminating LED cluster (504e) is connected to the sixth output current flow path (512e), and the Tail-Stop Light LED cluster (504/) is connected to the seventh output current flow path (5127).
The driver device (506) comprises a buck converter (508) configured to receive input voltage from the power source (502) and generate a preconfigured driving voltage. The driver device (506) further comprises a seven current control devices (510i, 5IO2, 5IO3, 5IO4, 5IO5, 5106, and 5IO7) adapted to receive the preconfigured driving voltage as produced by the buck converter (508) and generate preconfigured constant driving currents along the seven output
current flow paths (512i, , 5127). In particular, to the first output current flow path (512i)
the first current control device (510i) is connected, to the second output current flow path (5122) the second current control device (5102) is connected, to the third output current flow path (5123) the third current control device (5103) is connected, to the fourth output current flow path (5124) the fourth current control device (5104) is connected, to the fifth output current flow path (512s) the fifth current control device (5IO5) is connected, to the sixth output current flow path (512e) the sixth current control device (510e) is connected, and to the seventh output current flow path (5127) the seventh current control device (5107) is connected. Each of the seven current control devices (510i, ...., 5IO7) produces constant
driving currents so as to maintain constant luminance of the 7 LED clusters (504i, , 504/)
connected thereto.
The driver device (506) further comprises seven voltage sensors (514i, ...., 5H7) connected to the seven current flow paths (512i, ..... 5127). In particular, the first voltage sensor (514i) is

connected to the first output current flow path (512i) so as to be downstream of the first current control device (510i). Likewise, the second voltage sensor (5142) is connected to the second output current flow path (512i) so as to be downstream of the second current control device (5IO2), the third voltage sensor (5143) is connected to the third output current flow path (5123) so as to be downstream of the third current control device (5IO3), the fourth voltage sensor (5144) is connected to the fourth output current flow path (5124) so as to be downstream of the fourth current control device (5104), the fifth voltage sensor (514s) is connected to the fifth output current flow path (512s) so as to be downstream of the fifth current control device (5IO5), the sixth voltage sensor (514e) is connected to the sixth output current flow path (512e) so as to be downstream of the sixth current control device (510e), and the seventh voltage sensor (5H7) is connected to the seventh output current flow path (5127) so as to be downstream of the seventh current control device (5IO7).
In particular, the first voltage sensor (514i) is adapted to sense a first output voltage (VOUTi) in the first output current flow path (512i) downstream of the first current control device (510i). Likewise, second voltage sensor (5142) is adapted to sense a second output voltage (VOUT2) in the second output current flow path (5122) downstream of the second current control device (5IO2). Similarly, the third voltage sensor (5143) is adapted to sense a third output voltage (VOUT3) in the third output current flow path (5123) downstream of the third current control device (5IO3). The fourth voltage sensor (5144) is likewise adapted to sense a fourth output voltage (VOUT4) in the fourth output current flow path (5124) downstream of the fourth current control device (5IO4). The fifth voltage sensor (514s) is similarly adapted to sense a fifth output voltage (VOUT5) in the fifth output current flow path (512s) downstream of the fifth current control device (5IO5). The sixth voltage sensor (514e) is adapted to sense a sixth output voltage (VOUTe) in the sixth output current flow path (512 6) downstream of the sixth current control device (510e). Last, but not the least, the seventh voltage sensor (5147) is adapted to sense a seventh output voltage (VOUT7) in the seventh output current flow path (5127) downstream of the seventh current control device (5IO7).
The driver device (506) further comprises a control unit (516). The control unit (516) is operatively coupled to the seven voltage sensors (514i, ...., 5147). The control unit (516) is adapted to receive the first to the seventh output voltages (VOUTi, VOUT2, VOUT3 VOUT4 VOUT5, VOUT6, VOUT7) from the seven voltage sensors (514i, ..... 5147).

The driver device (506) further comprises a memory unit (518) that stores seven threshold values (Ui, U2, U3, U4, U5, U6, and U7) corresponding to each of the first to the seventh output current flow path (512i, ...., 5127). The control unit (516) is coupled to the memory unit (518) and is adapted to retrieve the seven threshold values (Ui, U2, U3, U4, U5, U6, and U7). Furthermore, the control unit (516) is adapted to compare each of the seven output voltages with its corresponding threshold value (Ui, U2, U3, U4, U5, U6, and U7).
In particular, the control unit (516) compares the first output voltage (VOUTi) with the threshold value corresponding thereto (Ui) and determine "Front-Left Winker LED cluster (504i) having at least one LED short-circuit failure condition" in case the first output voltage (VOUTi) is equal to or less that the threshold value corresponding thereto (Ui). In an embodiment of the invention, in response to determining "Front-Left LED Winker cluster (504i) having at least one LED short-circuit failure condition" the control unit (516) is adapted to generate a "first current control device switch OFF signal".
Likewise, the control unit (516) compares the second output voltage (VOUT2) with the threshold value corresponding thereto (U2) and determine "Front-Right Winker LED cluster (5042) having at least one LED short-circuit failure condition" in case the second output voltage (VOUT2) is equal to or less that the threshold value corresponding thereto (U2). In an embodiment of the invention, in response to determining "Front-Right Winker LED cluster
(5042) having at least one LED short-circuit failure condition" the control unit (516) is
adapted to generate a "second current control device switch OFF signal".
Likewise, the control unit (516) compares the third output voltage (VOUT3) with the threshold value corresponding thereto (U3) and determine "Rear-Left Winker LED cluster
(5043) having at least one LED short-circuit failure condition" in case the third output voltage
(VOUT3) is equal to or less that the threshold value corresponding thereto (U3). In an
embodiment of the invention, in response to determining "Rear-Left Winker LED cluster
(5043) having at least one LED short-circuit failure condition" the control unit (516) is
adapted to generate a "third current control device switch OFF signal".
Similarly, the control unit (516) compares the fourth output voltage (VOUT4) with the threshold value corresponding thereto (U4) and determine "Rear-Right Winker LED cluster
(5044) having at least one LED short-circuit failure condition" in case the fourth output
voltage (VOUT4) is equal to or less that the threshold value corresponding thereto (U4). In an

embodiment of the invention, in response to determining "Rear-Right Winker LED cluster (5044) having at least one LED short-circuit failure condition" the control unit (516) is adapted to generate a "fourth current control device switch OFF signal".
Likewise, the control unit (516) compares the fifth output voltage (VOUT5) with the threshold value corresponding thereto (U5) and determine "Position LED cluster (504s) having at least one LED short-circuit failure condition" in case the fifth output voltage (VOUT5) is equal to or less that the threshold value corresponding thereto (U5). In an embodiment of the invention, in response to determining "Position LED cluster (504s) having at least one LED short-circuit failure condition" the control unit (516) is adapted to generate a "fifth current control device switch OFF signal".
Similarly, the control unit (516) compares the sixth output voltage (VOUTe) with the threshold value corresponding thereto (Ue) and determine "License Plate Illuminating LED cluster (504e) having at least one LED short-circuit failure condition" in case the sixth output voltage (VOUTe) is equal to or less that the threshold value corresponding thereto (Ue). In an embodiment of the invention, in response to determining "License Plate Illuminating LED cluster (504e) having at least one LED short-circuit failure condition" the control unit (516) is adapted to generate a "sixth current control device switch OFF signal".
Likewise, the control unit (516) compares the seventh output voltage (VOUT7) with the threshold value corresponding thereto (U7) and determine "Tail Stop Light LED cluster (5047) having at least one LED short-circuit failure condition" in case the seventh output voltage (VOUT7) is equal to or less that the threshold value corresponding thereto (U7). In an embodiment of the invention, in response to determining "Tail Stop Light LED cluster (5047) having at least one LED short-circuit failure condition" the control unit (516) is adapted to generate a "seventh current control device switch OFF signal".
The driver device (506) further comprises seven switching devices (520i, ...., 52O7) connected
to the seven current control devices (510i 5107). In particular, a first switching device
(520i) is connected to the first current control device (510i). Likewise, the second switching device (52O2) is connected to the second current control device (5IO2), the third switching device (52O3) is connected to the third current control device (5103), the fourth switching device (52O4) is connected to the fourth current control device (5IO4), the fifth switching device (520s) is connected to the fifth current control device (510s), the sixth switching

device (520e) is connected to the sixth current control device (510e), and the seventh switching (520/) is connected to the seventh current control device (5IO7).
Each of the seven switching devices (520i, ...., 52O7) is also connected to the control unit (516) such that the control unit (516) provides the "current control device switch OFF signal" to the respective switching device (520i, ...., 52O7). For example, the control unit (516) is adapted to provide the "first current control device switch OFF signal" to the first switching device (520i) thereby turning OFF the first current control device (510i).
Similarly, the control unit (516) is adapted to provide the "second current control device switch OFF signal" to the second switching device (52O2) thereby turning OFF the second current control device (5IO2)- Likewise, the control unit (516) is adapted to provide the "third current control device switch OFF signal" to the third switching device (52O3) thereby turning OFF the third current control device (5IO3). Similarly, the control unit (516) is adapted to provide the "fourth current control device switch OFF signal" to the fourth switching device (52O4) thereby turning OFF the fourth current control device (5IO4). Likewise, the control unit (516) is adapted to provide the "fifth current control device switch OFF signal" to the fifth switching device (520s) thereby turning OFF the fifth current control device (510s). The control unit (516) is adapted to provide the "sixth current control device switch OFF signal" to the sixth switching device (520e) thereby turning OFF the sixth current control device (510e). Similarly, the control unit (516) is adapted to provide the "seventh current control device switch OFF signal" to the seventh switching device (52O7) thereby turning OFF the seventh current control device (5IO7).
In an embodiment of the invention, the output voltage sensors may be resistor connected in shunt with the output current flow paths.
In an embodiment of the invention, each of the switching devices includes a transistor. It may be noted that operation of the switching device that are placed in conjunction with the current control devices come into picture only under "LED cluster having at least one LED short-circuit failure condition". Despite the above, the minimum voltage required for the circuit to function does not increase. Thus, the circuit does not need an increased minimum voltage for its proper functioning.

In an embodiment of the invention as shown in Figure 6, the control unit (616) detects "LED cluster having at least one LED short-circuit failure" condition, it may be further configured to generate an error signal. The control unit (616) may be connected to an error signal output device (622) and the control unit (616) may be further adapted to provide the error signal to the error signal output device (622). The error signal output device (622) may be a visual output providing device that may be disposed on the instrument cluster of the vehicle. Alternatively, the error signal output device (622) may be an audio output providing device that may be disposed at a suitable location on the vehicle.
In an embodiment of the invention, the control unit (616) may be further connected to an error signal storing unit (624) and the control unit (616) may be further adapted to provide the error signal to the error signal storing unit (624). The error signal thus stored on the error signal storing unit (624) may be used for diagnostic purposes.
In an example of the invention, if the control unit (616) determines "Front-Left Winker LED cluster (6041) having at least one LED short-circuit failure condition", the error signal may be provided so as to double the flashing rate of the Rear-Left Winker LED cluster (604s). Likewise, if the control unit (616) determines "Front-Right Winker LED cluster (6042) having at least one LED short-circuit failure condition", the error signal may be provided so as to double the flashing rate of the Rear-Right Winker LED cluster (6O44).
In another example of the invention, if the control unit (616) determines "Rear-Left Winker LED cluster (6O43) having at least one LED short-circuit failure condition", the error signal may be provided so as to double the flashing rate of the Front-Left Winker LED cluster (604i). Likewise, if the control unit (616) determines "Rear-Right Winker LED cluster (6O44) having at least one LED short-circuit failure condition", the error signal may be provided so as to double the flashing rate of the Front-Right Winker LED cluster (6042).
In an embodiment of the invention, the driver device (606) may comprise a capacitor (626) to act as a backup in an event of non-availability of input voltage from the power supply device (602).
In an embodiment of the invention, the driver device (606) may further comprise a reverse protection device (628) provided in a path between the power supply device (602) and the capacitor (626).

While certain present preferred embodiments of the invention have been illustrated and described herein, it is to be understood that the invention is not limited thereto. Clearly, the invention may be otherwise variously embodied, and practiced within the scope of the following claims.

WE CLAIM:

1.A driver device (206; 306; 406; 506; 606) for vehicular application, said driver device
being connected between a power supply device (202; 302; 402; 502; 602) and a
plurality of LED clusters (204i, n; 304i, , 3047; 404i, , 404n; 504i, , 5047;
604i, , 6047), the driver device defining plurality of current flow paths (212i, n;
312i, , 3127; 412i, , 412n; 512L , 5127; 612L , 6127), that are parallel to
each other and to which the plurality of LED clusters are connected, the driver device comprising:
a buck converter (208; 308; 408; 508; 608) configured to receive input voltage from the power source and generate a preconfigured driving voltage;
plurality of current control devices (210i, n; 310i, , 3107; 410i, , 410n;
510i, , 5IO7; 6IO1, , 6IO7), adapted to receive the preconfigured driving voltage
as produced by the buck converter and generate preconfigured constant driving currents along a plurality of current flow paths;
plurality of voltage sensors (214i, „; 314i, , 3147; 414i, , 414n; 514i,
, 5147; 614i, , 6147), connected to the plurality of the current flow paths such
that voltage in each current flow path after the corresponding current control device is detected; and
a control unit (216; 316; 416; 516; 616) adapted to determine "LED cluster having at least one LED short-circuit failure" condition if voltage detected by the voltage sensor connected thereto is equal to or less than a corresponding threshold value.
2. The driver device as claimed in claim 1, wherein each of the plurality of current flow
path is provided with a voltage sensor for sensing the output voltage (VOUTi n) in
the current flow path downstream of the current control device connected to the current flow path.
3. The driver device as claimed in claim 1, wherein the control unit is operably coupled
to a memory unit (218; 318; 418; 518; 618) that stores the threshold values (Ui, ....
Un) for all output current flow paths, the control unit being adapted to retrieve the
threshold values (Ui, .... Un) and compare the threshold values with the voltage
detected (VOUTi n) by the voltage sensors and determine "LED cluster having at
least one LED short-circuit failure" condition if:

VOUTy