FORM 2
THE PATENTS ACT, 1970
(39 OF 1970)
AND
THE PATENT RULES, 2003
COMPLETE SPECIFICATION
(See section 10 and rule 13)
“SENSOR LESS STANDALONE STEP DIMMING LED LUMINAIRE TECHNOLOGY”
We, Bajaj Electricals Limited, an Indian National, of 45/47, Veer Nariman Road, Fort, Mumbai- 400001, Maharashtra, India
The following specification particularly describes the invention and the manner in which it is to be performed.

FIELD OF INVENTION
The present invention generally relates to lighting controls. In particular, the present invention provides a control circuit comprising modules for modifying the luminance of at least an LED for a time period for optimal lighting and power consumption.
BACKGROUND OF THE INVENTION
Lighting, particularly street lighting in cities, etc. is an essential, indispensable, and integral part of any civic plan. Lighting is important not only for general security, but also visibility of the area for vehicles, and pedestrians. However, most lighting systems are manually operated from a central location (on/off) and give a constant/ steady luminesce irrespective of external brightness conditions. This can conceivably lead to inefficient use of resources, such as power supply.
There are some “smart” technologies, whereby sensors are incorporated into such lighting systems, which detect external lighting and accordingly switch on/off the lights. However, such systems are generally expensive and not self-contained in that they depend on external signals to regulate the lighting. Therefore, there is a need to develop truly autonomous systems which are not dependent upon external signals/ cues and yet are able to regulate lighting operation for optimal power usage and lighting at the same time.
SUMMARY OF THE INVENTION
In an aspect of the present invention, there is provided a control circuit for modifying the luminance of at least a LED for at least a time period, said control circuit comprising: (a) at least a timer module adapted to select one of a plurality of pre-defined time periods and initiate a countdown of the selected pre-defined time period to 0; (b) at least a LED luminosity module adapted to select one of a plurality of pre-defined luminosity values; and (c) at least a power supply module adapted to select one of a plurality of pre-defined current values

for supply to the LED, wherein the luminance of the LED is varied in a time-dependent manner for optimal power consumption.
In an aspect of the present invention, the selected pre-defined luminosity value is based on the selected pre-defined current value.
In an aspect of the present invention, the selected pre-defined time period is associated with at least a duty-cycle value (n), where n is a whole number ≥ 2, and n ≤ t, where t is equal to number of plurality of pre-defined time periods.
In another aspect of the present invention, the at least a duty-cycle value (n) is associated with at least a pre-defined current value.
In yet another aspect of the present invention, the control circuit comprises a loop module, wherein said loop module is adapted to select a first duty-cycle value (n1); and select a second duty-cycle value (n2) when the countdown of the time-period associated with duty-cycle n1 hits 0; and when n2 = nt (nt being the upper-limit of duty-cycle value), the loop module reselects the first duty-cycle n1.
In still another aspect of the present invention, the said modules are comprised in at least a microcontroller, ASIC, or a microprocessor.
In another aspect of the present invention, the modules are collectively an autonomous module capable of modifying the luminance of at least an LED for at least a time period without requiring external sensory inputs.
In an aspect of the present invention, there is provided a method for controlling the luminance of at least an LED for at least a time period, said method comprising: (a) a loop module selecting a first-duty cycle value (n1) and initiating a countdown by a timer module of a pre-defined time period associated with said selected first duty-cycle (n1); (b) a power supply module selecting a pre¬defined current value to supply to the LED based on the duty-cycle value; and (c) a LED luminosity module selecting a pre-defined luminosity value based on the selected pre-defined current value, wherein said selected pre-defined luminosity

value controls the luminance of the LED in a time-dependent manner; and said modules are comprised in a control circuit, said control circuit comprising: (i) at least a timer module adapted to select one of a plurality of pre-defined time periods and initiate a countdown of the selected pre-defined time period to 0; (ii) at least a LED luminosity module adapted to select one of a plurality of pre¬defined luminosity values; and (iii) at least a power supply module adapted to select one of a plurality of pre-defined current values for supply to the LED, wherein the luminance of the LED is varied in a time-dependent manner for optimal power consumption.
In another aspect of the present invention, the loop module is adapted to select a first duty-cycle value (n1); and select a second duty-cycle value (n2) when the countdown of the time-period associated with duty-cycle n1 hits 0; and when n2 = nt (nt being the upper-limit of duty-cycle value), the loop module reselects the first duty-cycle n1, and where n is a whole number ≥ 2, and n ≤ t, where t is equal to number of plurality of pre-defined time periods.
In an aspect of the present invention, there is provided a plurality of LEDs in a geospatially defined area for providing varied illuminance to said area, wherein the varied illuminance of the plurality of the LEDs is controlled by at least a control circuit comprising: (i) at least a timer module adapted to select one of a plurality of pre-defined time periods and initiate a countdown of the selected pre-defined time period to 0; (ii) at least a LED luminosity module adapted to select one of a plurality of pre-defined luminosity values; and (iii) at least a power supply module adapted to select one of a plurality of pre-defined current values for supply to the LED, wherein the luminance of the LED is varied in a time-dependent manner for optimal power consumption.
This summary is not intended to identify the essential features of the invention nor is it intended for use in determining or limiting the scope of the claimed subject matter.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
The following drawings form part of the present disclosure and are intended to be illustrative to better explain the invention and the embodiments herein, but are not to be construed as limiting the scope of the invention.
Figure 1 depicts in a diagrammatic representation the control circuit and modules for modifying the luminance of at least an LED for at least a time period, in accordance with an embodiment of the present invention.
Figure 2 depicts an exemplary graph of a plurality of duty-cycles, each associated with a time-period and luminosity value, in accordance with an embodiment of the present invention.
Figure 3 depicts in diagrammatic form the cycling of a plurality of duty-cycles, each associated with a time-period and luminosity value, in accordance with an embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
Those skilled in the art will be aware that the invention described herein is subject to variations and modifications other than those specifically described. It is to be understood that the invention described herein includes all such variations and modifications. The invention also includes all such features referred to or indicated in this specification, individually or collectively, and any and all combinations of any two or more of said features.
For convenience, before further description of the present invention, certain terms/ definitions employed in the specification should be read in light of the remainder of the disclosure and understood as by a person of skill in the art. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by a person of ordinary skill in the art.
The present invention provides a control circuit (100) for modifying the luminance of at least a LED (110) for at least a time period, said control circuit comprising: (a) at least a timer module (102) adapted to select one of a plurality of pre-defined time periods and initiate a countdown of the selected pre-defined

time period to 0; (b) at least a LED luminosity module (104) adapted to select one of a plurality of pre-defined luminosity values; and (c) at least a power supply module (108) adapted to select one of a plurality of pre-defined current values for supply to the LED (110), wherein the luminance of the LED (110) is varied in a time-dependent manner for optimal power consumption.
In an embodiment of the present invention, the timer module (102) can store 1 pre-defined current value. In another embodiment, the timer module (102) can store up to 2 pre-defined current values. In yet another embodiment, the timer module (102) can store more than 2 pre-defined current values.
In an embodiment of the present invention, the control circuit (100) comprises 1 LED luminosity module (104) electrically connected with power supply module(s) (106). The LED luminosity module (104) has a plurality of pre-stored LED luminosity values. In an embodiment, a first pre-stored LED luminosity value is associated with a first pre-defined current value stored in timer module (102). In another embodiment, a first pre-stored LED luminosity value is associated a plurality of pre-defined current value stored in timer module (102).
In an embodiment of the present invention, the control circuit (100) comprises a single timer module (102). In another embodiment, the control circuit (100) comprise multiple timer modules (102). In an embodiment, the timer module (102) has at least 2 pre-defined time periods. In another embodiment, the timer module (102) has more than 2 pre-defined time periods. Each of the pre-defined time periods can be in seconds, minutes, hours days, or combinations thereof. The timer module (102) is adapted to select a first pre¬defined time period based on value of selected pre-define current value. Any one pre-defined time-period is associated with a duty-cycle value (n), where n is a whole number ≥ 2, and n ≤ t, where t is equal to number of plurality of pre¬defined time periods. In an embodiment, t=2. In an embodiment, t=3. In another embodiment, t=4. In yet another embodiment, t=5, 6, 7, 8, 9, 10 or the like. In an

embodiment, each duty-cycle has the same time period. In another embodiment, each duty-cycle has different time periods. In yet another embodiment, 2 or more duty-cycle may have the same time period. In an embodiment, upon selection of a pre-defined time period, the timer module (102) initiates a countdown of the selected pre-defined time period to 0. In an embodiment, the first pre-defined time period is associated with a first duty-cycle (n1). In a preferred embodiment, each of the pre-defined time periods of each duty-cycle can be reprogrammed such that the time associated with a particular duty-cycle can be varied. In an embodiment, the number of pre¬defined time periods can be reprogrammed, such that nt can be varied.
In an embodiment of the present invention, the timer module (102) can be programmed via Wi-Fi. In another embodiment, the timer module (102) can be programmed via Bluetooth. In another embodiment, the timer module (102) can be programmed via cellular technology. In a preferred embodiment, the timer module (102) can be programmed via at least a wired port, such as, but not limited to ethernet.
The control circuit of the present invention further comprises a loop module (108), wherein said loop module (108) is adapted to select a first duty-cycle value (n1); and select a second duty-cycle value (n2) when the countdown of the time-period associated with duty-cycle n1 hits 0; and when n2 = nt (nt being the upper-limit of duty-cycle value), the loop module (108) reselects the first duty-cycle n1. It is understood that when the loop module (108) selects the second duty-cycle (n2), the timer module (102) initiates countdown of second duty-cycle (n2) to 0.
In an embodiment of the present invention, the timer module (102) and the loop module (108) are provided in a single unit/ module. In another embodiment, the timer module (102) and the loop module (108) are provided in separate units/ modules.
In an embodiment of the present invention, in the event of loss of

external current supply to control circuit (100), the first duty-cycle n1 is selected by default and the time countdown associated with duty-cycle n1 is restarted.
In an embodiment of the present invention, any one or more of the timer module (102), LED luminosity module (104), power supply module (106), and loop module (108) is comprised in one or more microprocessor. In an embodiment, any one or more of the timer module (102), LED luminosity module (104), power supply module (106), and loop module (108) is comprised in one or more ASIC. In an embodiment, any one or more of the timer module (102), LED luminosity module (104), power supply module (106), and loop module (108) is comprised in one or more microprocessor.
The one or more of the timer module (102), luminosity module (104), power supply module (106), and loop module (108) of the control circuit (100) of the present invention are collectively an autonomous module capable of modifying the luminance of at least an LED (110) for at least a time period without requiring external sensory or. control inputs.
The control circuit (100) of the present invention can modulate the luminance of the LED (110) in a pre-defined manner by cycling through two or more LED luminance values for optimal lighting and power consumption. The said modulation of LED luminance is programmable. The said modulation of LED luminance is pre-determined and not real-time. In other words, the control circuit (100) does not require external environmental or control inputs to optimize power consumption or lighting requirement based on external daylight condition.
The present invention also provides a method for controlling the luminance of at least an LED for at least a time period, said method comprising: (a) a loop module (108) selecting a first-duty cycle value (n1) and initiating a countdown by a timer module (102) of a pre-defined time period associated with said selected first duty-cycle (n1); (b) a power supply module (106) selecting a pre-defined current value to supply to the LED based on the duty-cycle value;

and (c) a LED luminosity module (104) selecting a pre-defined luminosity value based on the selected pre-defined current value, wherein said selected pre¬defined luminosity value controls the luminance of the LED (110) in a time-dependent manner. The modules are comprised in a control circuit (100) as substantially described herein.
The present invention further provides a plurality of LEDs in a geospatially defined area for providing varied illuminance to said area, wherein the varied illuminance of the plurality of the LEDs is controlled by at least a control circuit (100) as substantially described herein.
In an embodiment, a single control circuit (100) controls a plurality of LEDs in a geospatially defined area. In another embodiment, multiple control circuits (100) control a plurality of LEDs in a geospatially defined area. In an embodiment, the plurality of LEDs have synchronous duty-cycle (n1). In another embodiment, the plurality of LEDs have asynchronous duty-cycle.
EXAMPLES
In an exemplary implementation of the present invention, Fig. 1 shows a layout of the control circuit (100) comprising various modules. As seen in in Fig. 1, the circuit (100) comprises a loop module (108) and a timer module (102) which are comprised in a single unit/ module, whereby the loop module (108) selects a first duty-cycle n1 and the timer module (102) initiates a time countdown associated with the selected duty cycle. Based on the selected duty-cycle, the LED luminosity module (104) selects a pre-determined LED luminosity value and the power supply module (106) selects a current value based on the selected LED luminosity value and sends it to the LED. It is to be understood that while the modules are depicted in a particular manner, the communication between the various modules may be in parallel and/or in a sequence.
In an exemplary implementation of the present invention, Fig. 2 shows a graph of a plurality of duty-cycles, each associated with a time-period and luminosity value. As seen in Fig. 2, the control circuit (100) has 3 different

luminosity value, namely, A, B, and C. The control circuit (100) has 3 duty-cycles (n1, n2, and n3). Duty-cycle n1 is associated with X time period; duty-cycle n2 is associated with Y time period; and duty-cycle n3 is associated with Z time period. At the initiation of duty-cycle n1, the LED is at luminosity A and the time period X starts countdown to 0. When time period X reaches 0, duty-cycle n2 is selected, luminosity of LED switches from A to B and the time period Y associated with duty-cycle n2 starts countdown to 0. When time period Y reaches 0, duty-cycle n3 is selected, luminosity of LED switches from B to C and the time period Z associated with duty-cycle n3 starts countdown to 0. When time period Z countdown reaches 0, duty-cycle n1 is reselected (not shown).
Fig. 3 shows in diagrammatic form the cycling as depicted in Fig. 2 and as explained above. As seen in Fig. 3, when the cycle starts, a first duty-cycle n1 with pre-defined time period X is selected and the countdown is initiated. The luminosity of LED associated with duty-cycle n1 is A (no dimming; 100% luminosity). While the current time (CT) of the countdown is not 0, the LED operates at luminosity A. When CT hits 0, a second duty-cycle n2 with pre¬defined time period Y is selected and the countdown is initiated. The luminosity of LED associated with duty-cycle n2 is B (25% dimming; 75% luminosity). While the current time (CT) of the countdown is not 0, the LED operates at luminosity B. When CT hits 0, a third duty-cycle n3 with pre-defined time period Z is selected and the countdown is initiated. The luminosity of LED associated with duty-cycle n3 is C (50% dimming; 50% luminosity). While the current time (CT) of the countdown is not 0, the LED operates at luminosity C. when CT hits 0, duty-cycle n1 is again selected.
It is to be noted that the number of dimming steps (duty-cycle) and time period associated with each dimming step is not a limiting factor. The number of steps and time period of each step can be varied and reprogramed independent of other duty cycles.
In another example, a 120W LED operated between 6pm-6am (12 hours)

without any step-dimming or modulation consumes 1.434kWh. The luminosity is constant irrespective of actual requirement (presence of traffic/ pedestrians etc.). The same 120W LED operated between 6pm-6am (12 hours), with 3 duty-cycles (n1, n2, and n3). n1 duty-cycle time period being 4 hours (no dimming); n2 duty-cycle time period being 2 hours (25% dimming); and n3 duty-cycle time period being 6 hours (50% dimming). The power consumption in this case is 1.024kWh, which is about a 30% power saving compared to no dimming. It is to be appreciated that in both cases, the lighting requirement is met adequately.
ADVANTAGES OF THE INVENTION
The control circuit (100) of the present invention is a simple constructional feature and economically beneficial. Power requirement can be reduced by at least 25% in certain pre-defined periods by reducing the luminosity of the LEDs, based on time of day/ night; pedestrian/ traffic activity. The control circuit (100) is modular, scalable and programable. There is no requirement of dimmable driver and external signal/external input/ sensors/ concentrators/ monitoring system. The common constructional features can accommodate a wide variety of duty-cycles and time periods.
REFERENCE NUMERALS
(100) Control circuit
(102) Timer module
(104) LED luminosity module
(106) power supply module
(108) loop module
(110) LED

We Claim
1. A control circuit (100) for modifying the luminance of at least a LED (110)
for at least a time period, said control circuit comprising:
a. at least a timer module (102) adapted to select one of a plurality
of pre-defined time periods and initiate a countdown of the
selected pre-defined time period to 0;
b. at least a LED luminosity module (104) adapted to select one of a
plurality of pre-defined luminosity values; and
c. at least a power supply module (106) adapted to select one of a
plurality of pre-defined current values for supply to the LED (110),
wherein the luminance of the LED (110) is varied in a time-dependent manner for optimal power consumption.
2. The control circuit (100) as claimed in claim 1, wherein the selected pre¬defined luminosity value is based on the selected pre-defined current value.
3. The control circuit (100) as claimed in claim 1, wherein the selected pre¬defined time period is associated with at least a duty-cycle value (n), where n is a whole number ≥ 2, and n ≤ t, where t is equal to number of plurality of pre-defined time periods.
4. The control circuit (100) as claimed in claim 3, wherein at least a duty-cycle value (n) is associated with at least a pre-defined current value.
5. The control circuit (100) as claimed in claim 3, comprising a loop module (108), wherein said loop module (108) is adapted to select a first duty-cycle value (n1); and select a second duty-cycle value (n2) when the countdown of the time-period associated with duty-cycle n1 hits 0; and when n2 = nt (nt being the upper-limit of duty-cycle value), the loop module reselects the first duty-cycle n1.

6. The control circuit (100) as claimed in claims 1-6, wherein said modules are comprised in at least a microcontroller, ASIC, or a microprocessor.
7. The control circuit (100) as claimed in claim 1, said modules are collectively an autonomous module capable of modifying the luminance of at least an LED (110) for at least a time period without requiring external sensory and control inputs.
8. A method for controlling the luminance of at least an LED (110) for at least a time period, said method comprising:
a. a loop module (108) selecting a first-duty cycle value (n1) and
initiating a countdown by a timer module (102) of a pre-defined
time period associated with said selected first duty-cycle (n1);
b. a power supply module (106) selecting a pre-defined current value
to supply to the LED based on the duty-cycle value; and
c. a LED luminosity module (104) selecting a pre-defined luminosity
value based on the selected pre-defined current value,
wherein said selected pre-defined luminosity value controls the luminance of the LED (110) in a time-dependent manner; and said modules are comprised in a control circuit as claimed in claim 1.
9. The method as claimed in claim 8, wherein the loop module (108) is adapted to select a first duty-cycle value (n1); and select a second duty-cycle value (n2) when the countdown of the time-period associated with duty-cycle n1 hits 0; and when n2 = nt (nt being the upper-limit of duty-cycle value), the loop module (108) reselects the first duty-cycle n1, and where n is a whole number ≥ 2, and n ≤ t, where t is equal to number of plurality of pre-defined time periods.
10. The method as claimed in claim 8, said modules are collectively an autonomous module capable of controlling the luminance of at least an LED (110) for at least a time period without requiring external sensory and control inputs.

11. A plurality of LEDs in a geospatially defined area for providing varied illuminance to said area, wherein the varied illuminance of the plurality of the LEDs is controlled by at least a control circuit (100) as claimed in claim 1.