Photocell enclosure comprising an integrated photocell and LED driver circuit

Abstract

Disclosed is a photocell enclosure comprising an ambient light sensor, a photocell electronic circuit for controlling the operation of the ambient light sensor, and an associated external LED luminaire light engine or an LED Chip on board (COB), and an LED photocell driver circuit. The LED photocell driver circuit is communicatively coupled to the photocell electronic circuit for providing an output low voltage DC power to the LED luminaire light engine or the LED COB, wherein the LED photocell driver circuit is configured to operate in sync with the photocell electronic circuit that delivers the dusk to dawn, the part-night or dimming control of the LED engine, wherein the photocell enclosure is a twist lock mounting type photocell of at least four pins

Description

[0001] Title

[0002] Photocell enclosure comprising an integrated photocell and LED driver circuit

[0003] Field

[0004] The present disclosure relates to a photocell, and more particularly to LED light engine driver circuit within a photocell enclosure.

[0005] Background

[0006] In streetlighting systems, the use of DC rather than AC is a new emerging technology means of delivering a low voltage DC supply as for example: a solar source of 48Volts DC or other various DC power voltages. This means, that the future streetlighting can be powered from alternative energy sources such as solar energy panels that delivers direct current. In AC systems, the AC power has to converted to DC, as all electronic devices in the present world today operate only on DC power. Also, along with an AC LED Light Engine driver, a Low voltage DC LED Light Engine Driver in streetlighting is advancing due to it being a sustainable lighting solution and especially as energy costs increase. More and more streetlights are being connected to 48Volts DC solar power supplies and other various DC non solar power supply installations as was the case with the present varying 85VAC to 520 Mains AC grid systems. Also, regarding DC systems, the requirement to replace old mains streetlight cabling is not necessary, once low voltage DC streetlighting is employed, delivering large installation savings and safety from accidental electrocution.

[0007] Further, present LED drivers are mounted within the gear compartment of the LED luminaire. Presently, the following procedure must take place to replace a faulty LED streetlight driver or upgrade to a new more beneficial LED driver. Firstly, the incoming mains supply to the streetlight must be disconnected. Next, the cherry picker basket is raised for the electrician to open the luminaire canopy. Then, the faulty LED driver is removed and replaced with a new driver. On some occasions, the LED Luminaire may have to be removed and the driver replaced in the maintenance depot. Then, it is replaced with a new driver, the LED streetlight canopy is fitted back, the cherry picker maintenance basket is lowered, and the mains supply is re-connected. Thus, replacing a faulty LED streetlight driver or upgrading to a new more beneficial LED driver in an LED luminaire is a very time-consuming procedure.

[0008] Also in the LED luminaire, the LED engine driver cannot use the cool night air to keep them operating at a low temperature. Also, there is heat generated by the light engine and some light engines operate up to 150 watts and higher and this heat circulates within the luminaire enclosure. The mounting of LED light engine drivers within the LED streetlight luminaire itself has no means of keeping it cool and protecting it from the heat of the light engine. Thus, 1 degree reduction of temperature doubles the life of the component, circuit or of an overall product. Also, mounting LED drivers within the LED luminaire can also be subjected to capillary action should the LED luminaire enclosure be badly sealed.

[0009] US2016 / 0286619 discloses a lighting fixture that includes an outer frame, a solid-state light source, a lens, and a sensor module connector. The driver circuitry is coupled to the outer frame and provides one or more drive signals for powering the light source. However, the mounting of driver circuitry within the lighting fixture has no means of keeping it cool and protecting it from the heat. GB2530298 refers to a light sensor for use with a light assembly and a control circuit connected to the light sensor and this light sensor circuit is mounted and connected internally within the Luminaire. However, said system too suffers from the disadvantages associated with the mounting of driver circuitry within the lighting fixture.

[0010] WO201 4 / 124501 discloses an OLC outdoor lighting controller with an ambient light sensor fitted within the photocell enclosure similar to all standard photocells. Furthermore, WO201 4 / 124501 describes a 3 pin ANSI / NEMA twist lock photocell with just 3 pins for inserting into a 3 pin ANSI / NEMA standard socket. US2003 / 0010901 discloses a photo switching device that includes first, and second terminals respectively coupled to a power source and a load. US5908235 discloses an integrated, electronic fluorescent ballast fixture which includes an electronic ballast packaged with a set of fluorescent lamp connectors into an integral fixture. US4874989 discloses an electronic ballast that powers fluorescent lamps in a lighting fixture with a current of magnitude related to the frequency of the ballast output voltage. DE 19521934 discloses a lighting unit that includes an integral dimmable electronic ballast which can be adjusted by means of a potentiometer fitted to the inside or outside of the light.

[0011] In view of the above, there is a need for a system that overcomes the disadvantages associated with installing the LED light engine drivers within the LED luminaire enclosure.

[0012] SUMMARY OF INVENTION

[0013] In an aspect of the present invention, there is provided a photocell enclosure that includes an integrated photocell and LED driver system, as set out in the appended claims. The photocell enclosure comprises an ambient light sensor, a photocell electronic circuit for controlling the operation of the ambient light sensor, and an external associated LED luminaire light engine or an LED Chip on board (COB). The photocell enclosure further includes an LED photocell driver circuit communicatively coupled to the photocell electronic circuit for providing an output low voltage DC power to the LED luminaire light engine or the LED COB, wherein the LED photocell driver circuit is configured to operate in sync with the photocell electronic circuit that delivers the dusk to dawn, the part-night or dimming control of the LED engine. In an embodiment of the present invention, the LED photocell driver circuit includes an DC to DC constant current LED driver or an AC to DC converter that comprises first and second capacitors connected in parallel to the LED light engine, and wherein an incoming AC mains supply is provided alternately to the first and second capacitors, leading to a phase shift between the voltage and current, thereby supplying only positive reactive power to the LED light engine. The photocell enclosure is a twist lock mounting type photocell of at least four pins.

[0014] In an embodiment of the present invention, the LED photocell driver circuit receives a DC to DC constant current or alternatively an AC mains input and generates a predefined DC output.

[0015] In an embodiment of the present invention, a normal load outline to the LED Light engine is connected from the photocell driver that is connected to an incoming DC supply or alternatively an AC mains supply to the photocell driver circuit.

[0016] In an embodiment of the present invention, the AC LED photocell driver circuit is an LC circuit with an electromagnetic coil, represented by an incoming mains grid, a capacitor and an indictive or capacitive resistance represented by the LED light engine.

[0017] In an embodiment of the present invention, the LED photocell driver circuit is a DC-to-DC constant current LED photocell driver circuit that operates on an incoming DC power supply.

[0018] In an embodiment of the present invention, the dusk to dawn operation of the photocell is either controlled by utilising a light sensor or remote command signal from a variety of sources.

[0019] In an embodiment of the present invention, the LED photocell driver circuit is enclosed within the photocell enclosure as an additional stacked printed circuit board.

[0020] In an embodiment of the present invention, the photocell enclosure is inserted into four, five or seven pin sockets mounted externally on top or bottom of an LED streetlight luminaire canopy or on a photocell wall or pole mounting bracket.

[0021] In an embodiment of the present invention, the LED photocell driver circuit consumes less than 1 Watt when in standby power.

[0022] In an embodiment of the present invention, the LED photocell driver circuit and the photocell electronic circuit have a power factor close to unity. In an embodiment of the present invention, the LED photocell driver circuit has an automatic re-start after a malfunction or a power outage.

[0023] In an embodiment of the present invention, the photocell enclosure is inserted into a twist lock socket or hardwired mounted on top of a streetlight canopy.

[0024] In an embodiment of the present invention, the photocell enclosure has an auxiliary output to provide auxiliary DC power to external smart city street loT systems.

[0025] In an embodiment of the present invention, the photocell complies with Zhaga Book 18 type photocell enclosure and DALI D4 type communications.

[0026] In an embodiment of the present invention, the photocell can receive or transmit control, monitoring and diagnostic and over the air updates from or to a remote location.

[0027] In an embodiment of the present invention, the photocell is designed to communicate with third party loT town and smart city devices.

[0028] In accordance with another aspect of the present invention, there is provided a method for operating a LED luminaire light engine. The method includes providing a photocell enclosure that includes an ambient light sensor and a photocell electronic circuit for controlling the operation of the ambient light sensor and the external associated LED luminaire light engine, wherein the photocell enclosure is a twist lock mounting type photocell of at least four pins; fitting an LED photocell driver within the photocell enclosure, wherein the LED photocell driver is communicatively coupled to the photocell electronic circuit for providing an output low voltage DC power to the LED luminaire light engine, wherein the LED photocell driver circuit is configured to operate in sync with the photocell electronic circuit that delivers the dusk to dawn, the part-night or dimming control of the LED engine, and wherein the LED photocell driver circuit comprises an DC to DC constant current LED driver or an AC electronic to DC LED light engine supply or an AC converter that comprises first and second capacitors connected in parallel to the LED light engine, and wherein an incoming AC mains supply is provided alternately to the first and second capacitors, leading to a phase shift between the voltage and current, thereby supplying only positive reactive power to the LED light engine; and inserting the photocell enclosure into four, five, six or seven pin sockets mounted externally on top or bottom of an LED streetlight luminaire canopy or on a photocell wall or pole mounting bracket.

[0029] Various embodiments of the present invention provide a photocell enclosure that includes an integrated photocell and LED driver circuit, thereby eliminating the requirement to fit a LED driver within a LED streetlight or general outdoor LED light. This eliminates the most time-consuming procedure of replacing a faulty LED streetlight driver or upgrading to a new more beneficial LED driver by delivering rapid insertion and removal during periods of installation and maintenance. The fitting of the LED driver within the photocell enclosure allows improved LED luminaire manufacturing assembly by reducing the number of modules required to manufacture a LED luminaire, thus improving manufacturing efficiency and reducing costs. The LED driver circuit can be fitted in the photocell enclosure during the streetlight installation phase and not during the LED luminaire component assembly phase. The installation of the LED driver within a photocell enclosure keeps the LED driver cool, protects it from the heat of the light engine, and eliminates subjecting the LED drivers to fluctuating temperatures and the damaging effects of moisture withing the LED luminaire enclosures.

[0030] Also, fitting of the LED driver within the photocell enclosure require the photocell enclosure to have a socket requiring more than 3 electrical pins. The photocell enclosure of the present invention can be either fit into a NEMA / ANSI or Zhaga 4 / 5 / or 7 pin twist lock mounting type photocell socket. The LED photocell driver can be inserted into the above mentioned 4 / 5 / and 7 pin twist lock sockets. The incorporation of a driver circuit fitted within a photocell enclosure makes use of the latest new and novel 4 / 5 and 7 pin ANSI / NEMA and Zhaga Book 18 twist lock sockets. Those mentioned sockets are mounted on the canopy of road, streetlight LED luminaires or any outdoor LED luminaire having such fitted sockets when utilised externally.

[0031] Further, the photocell enclosure is sealed to protect the electronics against the ingress of dust and water as they are been mounted externally to the light fixture. Also, this novelty keeps the photocell and LED driver electronics cool delivering a longer photocell and LED driver life.

[0032] The fitting of the LED driver circuitry into the photocell enclosure delivers ease of maintenance should the LED driver circuit fail. This allows the rapid maintenance of the outdoor lighting luminaire which can be mounted on a road, motorway, or street. Thus, changing the LED driver becomes the same as changing a photocell. Further, fitting of the LED driver circuitry can lead to reducing the size of LED luminaires, which will ensure it is less prone to high wind conditions and reduce the column vibrations and may be more aesthetically pleasing to the citizens and less prone to vandalism.

[0033] Further, the LED driver circuit of the present invention includes an innovative AC to DC converter that innovatively reduces the component count in all past and present AC powered LED driver circuits fitted within LED luminaires, by providing a circuit that includes two diodes and two capacitors that delivers the exact current and voltages depending on the capacitors selected to a wide variety of LED light engines.

[0034] BRIEF DESCRIPTION OF DRAWINGS

[0035] The invention will be more clearly understood from the following description of an embodiment thereof, given by way of example only, with reference to the accompanying drawings, in which:-

[0036] FIG.1 A illustrates an LED light engine photocell driver circuit, in accordance with an embodiment of the present invention;

[0037] FIG.1 B illustrates phase shifted voltage and current outputted by the LED light engine photocell driver circuit;

[0038] FIG.2A illustrates an exemplary photocell enclosure, which may be a standard ANSI / NEMA mains AC photocell;

[0039] FIG.2B illustrates an internal view of an integrated photocell and LED light engine photocell driver circuit; FIG.2C illustrates a detailed internal view of the integrated photocell and LED light engine photocell driver circuit, in accordance with an embodiment of the present invention; and

[0040] FIGs.2D and 2E illustrate a street lighting system including an integrated photocell and LED light engine photocell driver circuit, in accordance with an embodiment of the present invention.

[0041] DETAILED DESCRIPTION OF THE DRAWINGS

[0042] The embodiments in the invention described with reference to the drawings comprise a computer apparatus and / or processes performed in a computer apparatus. However, the invention also extends to computer programs, particularly computer programs stored on or in a carrier adapted to bring the invention into practice. The program may be in the form of source code, object code, or a code intermediate source and object code, such as in partially compiled form or in any other form suitable for use in the implementation of the method according to the invention. The carrier may comprise a storage medium such as ROM, e.g. a memory stick or hard disk. The carrier may be an electrical or optical signal which may be transmitted via an electrical or an optical cable or by radio or other means.

[0043] FIG.1 A illustrates an LED light engine photocell driver circuit 100, in accordance with an embodiment of the present invention. The LED light engine photocell driver circuit 100 receives an AC input, and generates a predefined DC output. In an example, the LED light engine photocell driver circuit 100 receives 220V / 230V 50 / 60Hz AC incoming supply. The LED light engine photocell driver circuit 100 may be enclosed within a photocell enclosure as an additional stacked printed circuit board. The LED light engine photocell driver circuit 100 may be hereinafter also referred to as the LED light engine photocell driver circuit, or the LED photocell driver circuit, or the LED driver photocell circuit. The LED light engine photocell driver circuit 100 is essentially an DC to DC constant current or an AC to DC converter, that includes two capacitors and two rectifiers or alternative DC circuits.

[0044] The LED light engine driver circuit 100 is designed as part of a photocell circuit, in that the normal load outline from the photocell is connected to an incoming mains supply to the LED driver circuit 100. This allows the photocell to control the LED driver circuit, switch it “On” at dusk and “Off” at dawn, switch it “On” at dawn or switch it “Off” at midnight called part-night or dim the streetlight at midnight or at different stages throughout the night.

[0045] In the LED driver circuit 100, the incoming mains supply (not shown) provides a resonance, sinusoidal signal to the line and neutral contacts. Both electrical potentials are provided alternatingly to one of the respective capacitors 104 and 106, depending on the current value. Due to this interplay between the incoming mains and both capacitors 104 and 106, the grid therefore only recognizes one capacitor and shifts the phase between the voltage 1 10 and current 1 12 by almost 90 degrees (See, FIG.1 B). Thus, the voltage 1 10 is up to 90 degree behind the current. In this situation, the power grid supplies only positive reactive power (+Q) and the active power is reduced to the level of the line losses.

[0046] The current delivered depends on capacitor selection regarding the different light engine wattages required. In an example, 250-450 AC mains is supplied to the capacitors 104 and 106, and capacitors vary from 2-30 microfarads depending on the required wattages.

[0047] The LED driver circuit 100 can be seen as one LC circuit with an electromagnetic coil (represented by the mains grid), a capacitor (106 or 104) and an indictive or capacitive resistance represented by the LED light engine 108. FIG.2A illustrates an exemplary photocell enclosure 200, which may be a standard ANSI / NEMA mains AC photocell. FIG.2B illustrates an internal view of an integrated photocell and LED driver system 203, which illustrates an ambient light sensor 202, a photocell electronics PCB 204, and an LED photocell driver circuit 206. The photocell 200 senses the ambient light through the ambient light sensor 202, and delivers power to both the photocell electronics circuitry 204 and the LED photocell driver circuit 206. The ambient light sensor 202 may be hereinafter referred to as a photocell.

[0048] In an embodiment of the present invention, the LED driver circuit 206 may be a DC to DC constant current photocell LED driver or an AC LED Photocell driver circuit (similar to one shown in FIG.1 ). The AC LED photocell driver is powered from the AC 220V - 230V mains high voltage system, and the DC to DC constant current LED photocell driver is powered from the low voltage DC 24V - 48V or other commonly used DC system. However, in the preferred embodiment, the LED driver circuit 206 is a DC LED photocell driver. The output of the DC LED photocell driver 206 is DC low voltage power.

[0049] The possibility of the LED driver circuit 206 being an DC to DC constant current LED photocell driver, or an AC LED photocell driver caters for present and past AC powered streetlights, and the emerging low powered developing smart loT city DC powered streetlights.

[0050] A DC streetlight powered system has an AC to DC converter power supply situated at up every 2.5kilometres along a city street, motorway or road supplying low voltage DC to the streetlight LED luminaires and the DC photocells. If solar panels are utilized, the voltage supply which is a low volage DC supply can be fed directly into the streetlighting grid. As more and more smart city loT sensors are being rolled out, DC powering systems are becoming more popular. FIG.2C illustrates a detailed internal view of the integrated photocell and LED driver enclosure 203, in accordance with an embodiment of the present invention. Enclosure 203 shows the LED photocell driver circuit 206 incorporated within a normal type of streetlight dusk to dawn photocell electronic circuitry 204.

[0051] Photocell electronic circuitry 204 may be a 4, 5 or 7 pin photocell powered through an AC mains or DC power source. Enclosure 203 may be inserted into the four, 5 or 7 pin NEMA / ANSI sockets 208 mounted externally on top of the LED streetlight luminaire canopies or on a photocell wall or pole mounting bracket. This means of mounting utilizes the cold night air to keep the LED driver circuitry cool. The golden rule of thumb is: one degree of heat reduction doubles the life of an electronic component or circuit. The integrated photocell and LED photocell driver 203 delivers a DC voltage to an LED luminaire light engine or chip on board (COB) LED 210 that provides the illuminance from the luminaire on to the road or city street.

[0052] The LED driver circuit 206 is configured to operate in sync with the photocell electronic circuitry 204 that delivers the dusk to dawn, the part-night or dimming control of the streetlight. The photocell electronic circuitry 204 controls and dims the LED light engine illumination combined in a single unit mounted on top or bottom of a LED luminaire 210 utilizing applicant’s novel Astro clock algorithms embedded within the photocell electronic circuitry to deliver the specified part-night switch off or dimming 204. These algorithms control the part-night switch off or dimming of the light engine throughout the LED driver’s activation period which is throughout the night. The dimming or mid-night switch off is critical, as the more accurate it is, the more energy is saved and the more sustainable the streetlight becomes. At dusk, the photocell activates the LED driver circuit 206, so the driver 206 can then activate the light engine to deliver the illumination. The photocell electronic circuit 204 delivers various commands throughout this driver activation period such as: mid-night switch off, reductions in light output (dimming) throughout the illumination activation period (nighttime). The photocell electronic circuit 204 constantly monitors and controls the LED light engine driver 24 / 7 regarding diagnostic information, driver operation period calculated as lamp burn hours to monitor streetlight energy used. As illustrated before, the LED driver circuit 206 may include a DC-to-DC constant current source LED driver circuit, or an AC LED driver circuit, or both. In an example, the low voltage DC to DC constant current type LED driver circuit is a low voltage DC LED driver. The integrated photocell and LED driver 203 may be mounted also on the underneath side of the LED streetlight luminaire 210. The enclosure 203 receives AC mains or low DC voltage (direct from a DC or AC streetlight system). The photocell electronic circuit 204 may deliver all the expected photocell features accurate dusk to dawn lighting control, partnight off and on at dusk, dimming schedules programmed to the required specifiers specifications. The LED driver circuit 206 may deliver the power to the LED light engine 210 to illuminate the streetlight with improved luminous efficacy. The efficacy is the measure of how well a light source produces visible light. The LED driver circuit 206 is very efficient in standby power mode. The innovative way that the circuit 206 is designed as energy efficient as there is a watch dog circuit that closes down non-essential circuit operation when it is not needed. Both the LED driver circuit 206 and the photocell electronic circuit 204 has a power factor close to unity. Also, the integrated photocell and LED driver 203 has an automatic re-start after a malfunction or a power outage and designed to deliver 24 / 7 continuous operation. This is accomplished by the embedded code software in the microcontroller inside photocell electronic circuitry 206. This software in constantly scanning the circuit in a power management mode feature in conjunction with many of the peripheral other functions, especially the interrupt and serial functions. This enables the photocell to also go into power-saving mode and to respond quickly to external events such as DC or AC power failure interruptions.

[0053] In an example, both the photocell electronic circuitry 204 and driver technology 206 may be compliant with Zhaga Book 18 and DALI D2 and D4i standards or other such protocols such 0 -10volts.

[0054] Like the standard ANSI / NEMA and Zhaga Book 18 photocells, the LED driver 206 may be easily inserted into the twistlock socket mounted on top of the streetlight canopy regardless of whether the incoming mains supply is connected or not. It is easy to remove by twisting and unplugging from the socket. The most beneficial feature of the photocell is it can be removed and replaced by hand without the need to disconnect the incoming AC or DC supply. Although not shown, the integrated photocell and LED driver circuit 203 may have an auxiliary outputs to provide auxiliary DC power and communications to external smart loT city systems, i.e. air quality monitoring, CCTV cameras etc.

[0055] In the specification the terms "comprise, comprises, comprised and comprising" or any variation thereof and the terms include, includes, included and including" or any variation thereof are considered to be totally interchangeable, and they should all be afforded the widest possible interpretation and vice versa.

[0056] The invention is not limited to the embodiments hereinbefore described but may be varied in both construction and detail.

Claims

Claims:

1. A photocell enclosure for operating a LED luminaire light engine, comprising: an ambient light sensor; a photocell electronic circuit for controlling the operation of the ambient light sensor and an LED photocell driver circuit; and an LED photocell driver circuit communicatively coupled to the photocell electronic circuit for providing an output low voltage DC power to the LED luminaire light engine or the LED COB, wherein the LED photocell driver circuit is configured to operate in sync with the photocell electronic circuit that delivers the dusk to dawn, the part-night or dimming control of the LED luminaire light engine, wherein the LED photocell driver circuit comprises an DC to DC constant current LED driver or an AC to DC converter that comprises first and second capacitors connected in parallel to the LED luminaire light engine, and wherein an incoming AC mains supply is provided alternately to the first and second capacitors, leading to a phase shift between the voltage and current, thereby supplying only positive reactive power to the LED luminaire light engine, and wherein the photocell enclosure is a twist lock mounting type photocell of at least four pins.

2. The photocell enclosure as claimed in claim 1 , wherein the photocell electronic circuit and the LED photocell driver circuit receives a DC voltage to deliver a constant current and or alternatively receives an AC main input, and generates a predefined DC output for powering the LED light engine.

3. The photocell enclosure as claimed in claim 1 , wherein a normal load out line from the LED photocell driver circuit is connected to an outgoing DC to DC constant current supply to the LED light engine or alternatively an AC mains supply to the AC LED photocell driver circuit supplying a DC output to the LED light engine.

4. The photocell enclosure as claimed in any preceding claims, wherein the AC LED photocell driver circuit is either an electronic LED driver or an AC LC driver circuit with an electromagnetic coil, represented by an incoming mains grid, a capacitor and an indictive or capacitive resistance represented by the LED light engine.

5. The photocell enclosure as claimed in claim 1 , wherein the LED photocell driver circuit is a DC LED photocell constant current driver circuit that operates on an incoming DC power supply source.

6. The photocell enclosure as claimed in any preceding claim, wherein the LED photocell driver circuit is enclosed within the photocell enclosure as an additional stacked printed circuit board.

7. The photocell enclosure as claimed in any preceding claim, wherein the photocell enclosure is inserted into four, five, six or seven pin sockets mounted externally on top or bottom of an LED streetlight luminaire or on a photocell wall or pole mounting bracket or alternatively hardwired through the canopy.

8. The photocell enclosure as claimed in any preceding claim, wherein the LED photocell driver circuit consumes less than 1 Watt when in standby power.

9. The photocell enclosure as claimed in any preceding claim, wherein the LED photocell driver circuit and the photocell electronic circuit have a power factor close to unity.

10. The photocell enclosure as claimed in any preceding claim, wherein the LED photocell driver circuit has an automatic re-start after a malfunction or a power outage.

11. The photocell enclosure as claimed in any preceding claim, wherein the photocell enclosure is inserted into a twist lock socket or hardwired mounted on top of a streetlight canopy.

12. The photocell enclosure as claimed in any preceding claim, wherein the photocell enclosure has an auxiliary output to provide auxiliary DC power or communications to external smart loT city street systems.

13. A method for operating a LED luminaire light engine, comprising: providing a photocell enclosure that includes an ambient light sensor and a photocell electronic circuit for controlling the operation of the ambient light sensor and the associated LED luminaire light engine, wherein the photocell enclosure is a twist lock mounting type photocell of at least four pins; fitting an LED photocell driver within the photocell enclosure, wherein the LED photocell driver is communicatively coupled to the photocell electronic circuit for providing an output low voltage DC power to the LED luminaire light engine, wherein the LED photocell driver circuit is configured to operate in sync with the photocell electronic circuit that delivers the dusk to dawn, the part-night or dimming control of the LED engine, and wherein the LED photocell driver circuit comprises an DC to DC constant current LED driver or an AC to DC converter that comprises first and second capacitors connected in parallel to the LED light engine, and wherein an incoming AC mains supply is provided alternately to the first and second capacitors, leading to a phase shift between the voltage and current, thereby supplying only positive reactive power to the LED light engine; and inserting the photocell enclosure into four, five, six or seven pin sockets mounted externally on top or bottom of an LED streetlight luminaire canopy or on a photocell wall or pole mounting bracket.

Images