Abstract: A method (50) of, a node device (100) and a computer program product arranged for alerting node devices in a network of operatively interconnected node devices by transmitting an alerting message comprising a geographic location address of an originator node device (21) transmitting the alerting message and a moving direction (12) of an object (11) receiving service from the originator node device (21). When a receiving node device (24, 25) determines, based on its geographic location address, the geographic location address of the originator node device (21) and the moving direction (12), that the object (11) is approaching the receiving node device (24, 25), it transmits the alerting message comprising the geographic location address of the originator node device (21) and the moving direction (12).

Abstract: A lighting device and system having at least one circuit, the circuit having at least two LEDs connected in series, parallel or anti-parallel configuration and at least one current limiting diode. The device or system may be driven with AC or DC power and may further include a sensor and polarity switching circuit to utilize all LEDs within the circuit when drive by DC power.

Abstract: A lighting apparatus includes a solar plate, a battery, a driver module, a light source, a lens tube, a main housing and a plugging bar. The solar plate converts a sunlight to an electricity. The battery stores the electricity. The driver module converts the electricity stored in the battery to a driving current. The solar plate is placed on a top side of the driver module and the light source is placed on a bottom side of the driver module. The lens tube has a top opening and a bottom opening. The top opening has a larger size than the bottom opening. The top opening is closer to the light source than the bottom opening. A light of the light source is emitted via a lateral lens surface of the lens tube between the top opening and the bottom opening.

Abstract: Implementations generally relate to systems, apparatuses, and methods for providing a modular sensor device in a residential environment. In some implementations, a modular sensor device includes a base that attaches to a wall in a living space. The modular sensor device also includes a power unit coupled to a first side of the base, where the power unit receives power from a power source, and where the power unit includes one or more devices that control conditions in an environment of the living space. The modular sensor device also includes a control module removably coupled to a second side of the base, where the module receives power from the power unit, and where the control module performs one or more predetermined control functions.

Abstract: The invention relates to a luminaire with a light source comprising: a functional unit; a power supply and control unit configured for converting power from a main power source into a power signal for powering the functional unit; wherein the power supply and control unit is configured to generate a power supply failure signal when the power supply from the main power source fails and to communicate the power supply failure signal to the functional unit.

Abstract: A lighting apparatus includes a solar plate, a battery, a driver module, a light source, a lens tube, a main housing and a plugging bar. The solar plate converts a sunlight to an electricity. The battery stores the electricity. The driver module converts the electricity stored in the battery to a driving current. The solar plate is placed on a top side of the driver module and the light source is placed on a bottom side of the driver module. The lens tube has a top opening and a bottom opening. The top opening has a larger size than the bottom opening. The top opening is closer to the light source than the bottom opening. A light of the light source is emitted via a lateral lens surface of the lens tube between the top opening and the bottom opening.

Abstract: A control device may be configured to control one or more electrical loads in a load control system. The control device may be a wall-mounted device such as dimmer switch, a remote control device, or a retrofit remote control device. The control device may include a gesture-based user interface for applying advanced control over the one or more electrical loads. The types of control may include absolute and relative control, intensity and color control, preset, zone, or operational mode selection, etc. Feedback may be provided on the control device regarding a status of the one or more electrical loads or the control device.

Abstract: A rail signal arrangement for a rail signaling system comprises a rail signal having a rail signal lamp including a plurality of light emitter sub-arrays each comprising a light emitter, wherein the light emitter sub-arrays are electrically connected in parallel. A control circuit is provided and configured to operate the rail signal lamp in response to operating instructions from a remote operations management system, detect the proportion of light emitter sub-arrays that are in an operable condition with a monitoring system, and provide a condition status signal to the remote operations management system in accordance with whether the proportion of light emitter sub-arrays in an operable condition meets a minimum threshold level.

Abstract: A control device may be configured to control one or more electrical loads in a load control system. The control device may be a wall-mounted device such as dimmer switch, a remote control device, or a retrofit remote control device. The control device may include a gesture-based user interface for applying advanced control over the one or more electrical loads. The types of control may include absolute and relative control, intensity and color control, preset, zone, or operational mode selection, etc. Feedback may be provided on the control device regarding a status of the one or more electrical loads or the control device.

Abstract: A loss of ground detection system includes a reference voltage source that provides a reference voltage, a primary ground connection that is adapted to be connected to a primary ground, a secondary ground connection that is adapted to be connected to a secondary ground, and an internal ground. The system also includes a combined ground integrity monitoring unit that outputs a multistage signal to control electronics. The multistage signal includes a first and a second output voltage. A first switch is interposed between the primary ground connection and the internal ground such that the first switch opens in response to loss of connection to the primary ground as indicated by a change of status in multistage signal, a diode system is interposed between the secondary ground connection and the internal ground, the diode system oriented to allow flow from the internal ground to secondary ground connection under forward bias.

Abstract: A lighting system for an operating room wherein machine-controlled light sources are Bluetooth™-enabled to allow them to locate and track the movement of a device worn on the hand or wrist of a surgeon or other operating room personnel. In preferred embodiments, the system described herein will accommodate light source tracking for multiple surgeon-worn devices worn by one or more wearers. The system is capable of toggling between modes of following the wearer's movement and focusing on a single point determined by the wearer, where mode swapping can be controlled by the surgeon from the device itself. The system preferably accommodates the adjustment of multiple characteristics of the light source, such as light intensity, from the hand or wrist device. A periphery ribbon may also be used to control the direction of light sources. Applications of the invention y stretch to other fields such as construction or theater lighting.

Abstract: A load control device may be configured to provide a user interface for controlling the intensity and/or color of one or more lighting loads. The user interface may include separate actuation members for setting the intensity and/or color of the lighting loads. The user interface may include one actuation member configured to operate in an intensity and/or color control mode. The control mode of the actuation member may be set via a button, a lever, a rotary switch, a rotary knob, etc. The user interface may include a touch sensitive element capable of sensing a user's touch and translate the touch into a control signal. Feedback may be provided on the user interface to indicate the type of control being adjusted and/or amount of control being applied to the lighting loads.

Abstract: An LED security light with an integrated motion sensor includes a PIR motion sensing unit and an LED load integrated together to become a compact lighting device. The PIR motion sensing unit is a two-portion design with a Fresnel lens either integrating with a light diffuser or as a separate piece positioned right behind the light diffuser and with a PIR motion sensor positioned at a focal point of the Fresnel lens and encircled by LEDs, wherein the Fresnel lens collects infrared ray signals generated by a moving body and remotely converges infrared ray signals on the PIR motion sensor. A signal processing circuitry decides whether the infrared ray signals represent an intrusion in order to turn on the compact lighting device. When the compact lighting device of this art is turned on, there is no shadow effect which reduces the lumens output of the security light.

Abstract: A portable image capture device includes a main body, an image capture assembly and a handle assembly. The main body includes a top surface, a bottom side disposed opposite the top surface, and an internal space disposed between the top surface and the bottom side. The image capture assembly disposed in the internal space faces the bottom side and performs image capturing. The handle assembly includes a handle part and a start button disposed beside the handle part. The handle assembly is disposed on the main body, and the image capture assembly is separated from the handle assembly and disposed under the top surface and above the bottom side so that a user uses one single hand to operate the portable image capture device and control image capturing timings.

Abstract: A light fixture includes a driver for driving a light engine based on control signals received from a controller coupled to the driver. The driver is further connected to an AC power source and is configured for detecting a power loss from the AC power source and generating a power loss signal. Upon detecting the power loss, the driver sends the power loss signal to the controller. Based on the power loss signal, the controller sends an emergency egress mode control signal to the driver which drives the light engine in the emergency egress mode, i.e. at its full intensity for an emergency time period. Upon expiration of the emergency time period or upon the recovery of the AC power, the controller exits the emergency egress mode by sending a normal control signal to the driver.

Abstract: The present disclosure provides a remote controller, a lighting device and a lighting system. The remote controller is configured for controlling color of light emitted by a target lighting device and includes: a housing; a main control panel of a remote control terminal, located in the housing and provided with a color acquiring circuit for acquiring color information of a target region, and a wireless transmitter for transmitting the color information to the target lighting device; a color acquiring switch, located on the housing and electrically connected with both the color acquiring circuit and the wireless transmitter, and the color acquiring switch being configured for turning on/off the color acquiring circuit and the wireless transmitter. The remote controller has a simple structure and convenient operation, so that the color of the light emitted by the lighting device may be freely adjusted according to individual needs, which is convenient.

Abstract: Disclosed is a spectral deficiency-driven control system in a plant growth automation, the system comprising: a facilities resource management system; a processor; a memory element coupled to the processor; encoded instructions; wherein the system is further configured to: over a network, receive at least one of a facility systems data; based on the received facility systems data, control an action via the facilities resource management system; wherein the received facility systems data is gathered via at least one facility sensor configured to detect facility-incoming and, or facility-generated light spectra and a sensor manager for determining a deficiency in light spectra; and wherein the actions controlled by the facilities resource management system is augmenting at least one of a spectral output of at least one light-emitting diode (LED) channel from at least one LED light source; light brightness; and, or a light height adjustment, based on the spectral deficiency.

Abstract: Control-source devices may be associated with control-target devices of a load control system during a configuration procedure, such that the control-target devices are responsive to the associated control-source devices during normal operation. The configuration procedure may be executed using a network device having a visual display for associating the control-source devices and control-target devices. The control-source devices may be associated with the control-target devices on an area-by-area basis using an area configuration procedure. The control-target devices may be configured to flash a controlled lighting load according to a flashing profile during the configuration procedure. The flashing profile may be characterized by at least one abrupt transition between off and on, and at least one gradual transition between off and on, where the abrupt and gradual transitions are repeated on a periodic basis.

Abstract: A temperature detection device includes a circuit board, a temperature sensor, and at least one signal transmission line. The temperature sensor is disposed on the circuit board and overlapped with a light source module, and the temperature sensor and the light source module forms a heat conduction path. The signal transmission line is connected to the circuit board to output a sensing signal of the temperature sensor.

Abstract: A driver for a lighting device includes: a lighting driver configured to drive LED(s) of the lighting device in a first mode of operation when a primary power source is available and provided to the lighting driver and to control power output and/or final output current utilizing a backup or other secondary power source during an emergency mode of operation. In example embodiments and implementations, the lighting driver includes a single instance of a LED driver (e.g., only one LED driver circuit) configured to drive LED(s) of the lighting device during both modes of operation.

Abstract: An emergency lighting ballast (100) includes: a power translation circuit (120) which receives input power from an emergency power source (10) and supplies output power to a load (20); a voltage monitor (130) that monitors voltage across the load and produces a voltage feedback signal; a current monitor (130) that monitors current across the load and produces a current feedback signal; a temperature sensor (160); and a programmable control device (140) which controls the power translation circuit (120) in response to either of the voltage feedback signal and the current feedback signal to cause the output power supplied to the load to have a programmed power output profile. The programmable control device also activates a self-test emergency state in response to a manual or preprogrammed request for a self-test, only if there is no power to the load as indicated by the voltage feedback signal and/or the current feedback signal.

Abstract: A light-diffusing optical element with efficient coupling to light sources with high numerical aperture. The light-diffusing optical element includes a higher index core surrounded by a lower index cladding. The cladding includes scattering centers that scatter evanescent light entering the cladding from the core. The scattered light exits the element to provide broad-area illumination along the element. Scattering centers include dopants, nanoparticles and/or internal voids. The core may also include scattering centers. The core is glass and the cladding may be glass or a polymer. The element features high numerical aperture and high scattering efficiency.

Abstract: Disclosed is a drive integrated circuit for controlling a traffic light. The drive IC comprises an input end and an output end, an input low-voltage control circuit, a gain control circuit, a driving circuit, an impedance loop and a phase detection circuit. The input low-voltage control circuit connects to the input end of the drive IC, and receives a first external signal. The gain control circuit connects to the input low-voltage control circuit. The driving circuit connects to the gain control circuit. The impedance loop connects to the input end to detect whether the traffic light is damaged. The phase detection circuit connects to the input end to detect a phase difference of the driving signal. By integrating circuits having different detection and control functions in one single chip, the cost of the drive IC decreases and the traffic light can have a less thick structure.

Abstract: Embodiments disclosed herein include methods for reducing or eliminating the impact of tuning disturbances during prediction of lamp failure. In one embodiment, the method comprises monitoring data of a lamp module for a process chamber using one or more physical sensors disposed at different locations within the lamp module, creating virtual sensors based on monitoring data of the lamp module, and providing a prediction model for the lamp module using the virtual sensors as inputs.

Abstract: A lighting-control processor (100, 300) for controlling operation of an external lighting unit comprises an exchange control unit, which is configured to control exchange of lighting-control information with the lighting unit via a lighting-control interface in accordance with an exchange protocol and to generate and provide exchange monitoring information indicative of an operational status of the exchange control unit. A reset unit is configured to receive a soft-reset command and to cause a soft reset of the lighting-control processor upon receiving the soft-reset command. An exchange watchdog unit is configured to receive the exchange monitoring information, determine validity of the exchange monitoring information in accordance with a predefined validity criterion, and to provide the soft-reset command upon detecting that the received exchange monitoring information is not valid.

Abstract: A strip of linear lighting with distributed power conversion is disclosed. The linear lighting includes a flexible PCB. The flexible PCB is divided into repeating blocks, which are arranged electrically in parallel with one another between power and ground. Each repeating block includes power conversion and conditioning circuits. A plurality of LED light engines are connected to the outputs of the power conversion and conditioning circuits, electrically in series with one another. The power conversion and conditioning circuits typically include at least a full-bridge rectifier, and a filter may be connected to each of the LED light engines. A pair of conductors run the length of the PCB adjacent to it and are connected to each of the repeating blocks. A flexible, transparent covering surrounds the PCB and pair of conductors.

Abstract: An embodiment method for short-circuit detection includes determining a set of local reference voltages each associated with a respective load chain in a plurality of load chains, and determining a global reference voltage in accordance with the set of local reference voltages. The method also includes determining, for each load chain in the plurality of load chains, a respective per-chain reference voltage in accordance with the global reference voltage, and comparing, for each load chain in the plurality of load chains, the respective per-chain reference voltage relative to a respective measured voltage across each load chain to determine a respective short-circuit condition.

Abstract: A color-changing lighting system includes a color temperature meter for determining a color temperature of visible light within an environment. The color-changing lighting system also includes a microprocessor for converting the color temperature of the visible light to red, green, and blue (RGB) values. The color-changing lighting system further includes a light control unit for calibrating a full spectrum color changing light source to output light having the color temperature of the visible light within the environment, according to the RGB values.

Abstract: The prevent invention provides a light-emitting device for providing a flash light source comprising a light-emitting module and a control module. The light-emitting module comprises a circuit substrate and a plurality of light-emitting elements disposed on the circuit substrate and electrically connected to the circuit substrate. The control module comprises a semiconductor switch element having a MOSFET for turning the light-emitting elements on or off, wherein the semiconductor switch element is electrically connected to the light-emitting elements thereby the light-emitting elements can flash via the semiconductor switch element alternately turning on and off the light-emitting elements.

Abstract: A liquid crystal display device is disclosed which includes a diagnosis controller configured to receive abnormity detection signals representing whether components of the liquid crystal display device are functioning normal. The components of the liquid crystal display device may include an LVDS interface, a timing controller, a data driver circuit, a backlight driver, a supply voltage generator. Such a liquid crystal display device handles treatable abnormities without any external help. In accordance therewith, complexity caused by transferring a large number of signals can be simplified.

Abstract: A semiconductor device is capable of detecting a power supply voltage abnormality without degrading the performance of internal circuits. The semiconductor device includes a plurality of power supply inspection circuits and a result storage register. The power supply inspection circuits detect a power supply voltage abnormality in each pad that couples an internal wiring disposed in the semiconductor device to another part disposed outside of the semiconductor device. The result storage register stores inspection results indicated by result signals output from the power supply inspection circuits.

Abstract: An indoor lighting fixture that includes a sensor to sense a condition associated with an indoor space and a first light source to emit an illumination light to illuminate the indoor space. The indoor lighting fixture further includes a second light source to emit a status indicator light to indicate a status from the sensor. A color temperature of the status indicator light is adjustable to substantially match a color temperature of the illumination light.

Abstract: A light source module includes at least one light source and a body supporting the light source. The body includes a heat sink supporting the light source on a top surface thereof for absorbing heat from the light source and dissipating the heat to the outside, an electrically insulating layer provided on at least one surface of the heat sink, and a conductive layer provided on the insulating layer, the conductive layer being at least provided in a path region through which electric current is applied to the light source. The conductive layer includes light source connection parts supplying the electric current to the light source, and a light source mounting part disposed between the light source connection parts. One portion of the light source connection part is divided into at least two portions to be connected to each other.

Abstract: Systems, devices, and methods for a decorative outdoor light fixture that can include an adjustable motion sensor with a rectangular coverage pattern. An adjustable motion sensor for a light fixture can include an outer housing connected to a light fixture frame, a movable sensor assembly including a motion detector contained within the outer housing, a lens covering a portion of the outer housing in the path of the motion detector sensing beams to direct the sensing beams in a rectangular coverage pattern, and a sensor adjustment mechanism accessible from an exterior of the outer housing to allow a user to rotate the sensor adjustment mechanism to cause the motion detector to move upward and downward. The adjustable motion sensor covered with a fixed window that hides the motion sensor assembly from view.

Abstract: An LED lighting system is provided for connection to a variable power source providing input power, the LED lighting system having at least one power analyzing and processing circuitry connecting to the variable power source, and being configured to identify one or more characteristics of the input power, where the characteristics are selected from amplitude, frequency and pulse width of the input power, compare one or more of the characteristics of the input power to preset control criteria either in hardware or software or both to yield a comparison result, and then control the current control circuitry according to the comparison result.

Abstract: Methods and apparatus for changing a DC supply voltage applied to a lighting circuit are disclosed. In specific cases, a constant voltage power supply is used to power an LED lighting circuit in which there are uncertainties within the forward voltages of the LEDs, which in turn creates uncertainty with respect to the current level flowing through the LEDs. To manage these uncertainties, the current flowing through the LEDs is measured and an indication of the current level is communicated to a person who can manually adjust the DC voltage supply applied to the LED lighting apparatus by the constant voltage power supply. Alternatively, an automatic adjustment of the DC voltage supply applied to the LED lighting apparatus by the constant voltage power supply can be performed based upon the measured current level.

Abstract: A wearable, ruggedized device incorporating an OLED display is provided. The device is capable of operating in multiple modes, such as a lower-brightness and/or higher-contrast mode. The use of multiple modes allows for reduced power requirements, while providing responsiveness and continuous availability of the device to a user.

Abstract: Apparatuses and methods are disclosed for determining a condition of an electronic lock that may include a keypad, determining at least one of a plurality of keys of the keypad to illuminate based on the condition, and illuminating at least one of the keys on the keypad to indicate the condition and/or provide an audible feedback.

Abstract: Fault protection circuitry and methodologies for isolated power supply topologies are provided. The circuitry is configured to shut down the primary side of the supply in case of a system fault, while keeping the secondary side circuit running, thus offering flexibility for restarting upon clearing of the fault. A lighting driver thus configured with safety isolation and a secondary side microcontroller or other control circuitry, is configured so that the circuit can shut down the primary side in response to system fault detection, while keeping the secondary microcontroller running from an energy storage circuit (e.g., bulk capacitor in parallel with load). The driver operation can resume with a controlled timing if the fault is cleared. The number of restarts may be limited, and/or a timer may be used to space restarts. The driver may be used with loads other than lighting-based loads, as will be appreciated.

Abstract: An electrical device such as a switch includes a light source and light sensor to detect ambient light and actuate the light source when the ambient light is below a predetermined level. The light switch has a pivotally mounted rocker actuator with a first outer face on one side of the pivot axis at a first end of the housing and a second outer face on a second side of the pivot axis at a second end of the housing. The light source is positioned in the housing to illuminate a light transmitting area of the first outer face of the actuator. The light sensor and a light sensor lens for directing ambient light to the light sensor are positioned at or near the second outer face at the second end of the housing.

Abstract: A multi-sensor lighting control system includes at least two light sensors. Each sensor gathers light from different sources, by comparing and contrasting the output signals from the two sensors, the controller can automate many lighting control and commissioning processes leading to easier, simpler installations and maintenance and happier customers, and removing the need for special tools. Applying automated closed loop lamp warm-up techniques, the daylight ratio and the maximum electric light contribution can be learned automatically by the system. A multi-sensor lighting control system may also provide intermediate zones of lighting control between adjacent task areas with different lighting requirements.

Abstract: Disclosed are elevated lights and methods of maintaining illumination in elevated lights for an airfield. The elevated lights have a substrate having a mounting surface, LEDs, a reflector, and an LED driver circuit. The LEDs are disposed on the mounting surface of the substrate and configured such that a primary illumination axis of each LED is oriented along a longitudinal axis of the elevated light. The reflector is configured such that the light emitted from the LEDs is reflected radially with respect to the longitudinal axis of the elevated light. The driver circuit is configured to provide a current to the LEDs and detect failure of one or more of the LEDs. Illumination is maintained by providing a current to the LEDs, detecting a voltage change across the LEDs, determining, based on the voltage change, LED failure, and altering the provided electrical current in order to maintain illumination.

Abstract: A multifunction socket device is connected to a main AC power and comprises a frame unit, at least one power outlet, a cover unit and a first illuminating unit. The multifunction socket device can provide power source and illumination device, which bring more convenience and options to modern lifestyle.

Abstract: A medical lighting device has an operating area light (100), a central control station (11), a lighting control unit (7), a control unit (39), an image detection element (27), an image processing unit (29), reference elements (67, 69), an operating unit (200), a position sensor (25), an operating element (33) arranged at a handle (31), a marking and distance detection element (35) and a device for data transmission (13, 15, 17, 19, 21, 26, 28). A horizontal-vertical position (58) of the operating unit (200) in the room and a light marking position (38) on a reclining surface (99) are determined by the position sensor (25), the marking and distance detection element (35), the image detection element (27) combined with reference elements (67, 69) and image processing unit (29). The operating area light (100) is actuated such that an illuminated area (71) is illuminated on the reclining surface.

Abstract: An elevator interior illumination assembly comprising a primary LED driver that provides conditioned DC power to primary and backup LEDs when AC power is available from a primary electric power source. The backup LEDs receive DC power from a backup electric power source when AC power is not available to the primary LED driver from the primary electric power source.

Abstract: A ballast circuit adapted for converting an input alternating current (AC) mains power received at input terminals to an output alternating current (AC) to supply a load, e.g. a gas discharge lamp. The output terminals of the ballast connect to the load in parallel with another ballast circuit. The ballast circuit is configured to supply the output AC current to the load in parallel with an AC current output of the other ballast circuit. A synchronization module attached at the output is adapted for synchronizing the output alternating current (AC) of the ballast circuit with the AC current output of the other ballast circuit. The synchronization module is configured to synchronize phase of the output alternating current with phase of the AC current output of the other ballast circuit.

Abstract: The present invention provides a LED backlight driving circuit, a backlight module, and a liquid crystal display device, wherein, the LED backlight driving circuit comprises: a power module, a voltage converting module, a constant current driving IC module, and a boost module. The output terminal of the power module is connected with the power source of the constant current driving IC module through the voltage converting module; the output terminal of the power module is connected with the positive electrode of the LED strings through the boost module. The boost module is provided with an over voltage alarm unit used to warn that the voltage of the positive electrode of the LED strings is high. In the present invention, it can warn immediately and notice the failures when the output voltage of the LED backlight driving circuit is too high or the failure happens.

Abstract: A programmable light timer for implementing a timing pattern is described. The programmable light timer comprises a memory storing a plurality of timing patterns, each timing pattern being associated with a unique timing pattern code and having one or more on/off settings for a time period; and a user interface enabling the selection of a timing pattern code associated with a timing pattern of the plurality of timing patterns.

Abstract: A driving circuit with an over-voltage protection device for modulating an electrical parameter of a driven device includes at least a boost circuit, a signal processing circuit, an over-voltage protection device, a modulation device and a control circuit. The output terminal of the boost circuit is electrically coupled in series to a driven device, a transistor and a grounded feedback resistor sequentially, wherein the output terminal of the boost circuit is further electrically coupled to a voltage dividing circuit for outputting a voltage dividing signal. The signal processing circuit is provided for outputting a processing signal to the over-voltage protection device and the modulation device according to the voltage dividing signal and a modulation signal. The control circuit is provided for turning on the transistor or not according to an output signal of the over-voltage protection device and an output signal of the modulation device.

Abstract: End-of-life indicators for lamps, and methods for indicating the end-of-life for lamps, are provided. A solid state light source end-of-life indicator is located on the exterior of a housing of a lamp, and includes at least one light emitting diode. The solid state light source end-of-life indicator emits light at the end of the life of the lamp. The solid state light source end-of-life indicator may emit light upon receiving an end-of-life signal from an end-of-life detection circuit, which detects when the lamp is at an end of its life.