摘要:
A fault detection mechanism for a LED string comprising a plurality of serially connected LEDs, the fault detection mechanism comprising: a control circuitry; and a voltage measuring means, in communication with the control circuitry, arranged to measure the voltage drop across at least one LED of the LED string, the control circuitry being operable to: measure the voltage drop, via the voltage measuring means, at a plurality of times, compare at least two of the measured voltage drops, and in the event the comparison of the at least two voltage drops is indicative of one of a short circuit LED and an open circuit LED, output a fault indicator.
摘要:
A redundant powering system for a powered device receiving power over communication cabling, the redundant powering system comprising: a redundant power supply comprising a first power sourcing equipment and a second power sourcing equipment; a powered device; communication cabling connecting the redundant power supply to the powered device, the communication cabling comprising a first path connecting the first power sourcing equipment to the powered device and a second path connecting the second power sourcing equipment to the powered device, the first and second paths at least partially being constituted of a single structured cable, the at least one powered device comprising at least one signature impedance, the redundant power supply being operable so that power is operably supplied to the powered device from only one of the first and second power sourcing equipment.
摘要:
A communication network utilizing Power Over Ethernet technology including Power Sourcing Equipment (PSE) that includes a multi-purpose device that operates as a current sensing resistor under normal electrical operating conditions and operates as a protection device, e.g., a fuse, under fault conditions, such as, an internal switch failure and an overload occurring simultaneously.
摘要:
A lighting circuit constituted of: a single dimming input; a pulse width modulation acceptance circuit arranged to convert a pulse width modulated dimming signal received at the single dimming input into a local dimming signal, the local dimming signal exhibiting a predetermined format; an analog voltage level acceptance circuit arranged to convert an analog voltage dimming signal received at the single dimming input into the local dimming signal exhibiting the predetermined format; and a luminaire driving circuit responsive to the local dimming signal.
摘要:
An LED driver arrangement wherein a low voltage IC is arranged to sample the voltage at a terminal of each of the respective electronically controlled switches controlling a plurality of LED strings each receiving power from a single source, with the single source providing voltage in excess of the voltage rating of the IC. For each electronically controlled switch a controllable current source and an isolating unidirectional electronic valve is provided, the respective current source being enabled only when the respective associated electronically controlled switch is at least partially closed thereby ensuring that the respective isolating unidirectional electronic valve associated with the respective illuminating LED string conducts, and the voltage at the terminal of the respective electronically controlled switch is thus seen by the IC when the associated LED string is producing illumination, the voltage then being lower than the maximum voltage rating of the IC.
摘要:
A backlighting system comprising: a color manager; a plurality of luminaires, each of the luminaires comprising a LED string and arranged to illuminate a particular portion of a display associated therewith; a color sensor arrange to receive light from one of the luminaires; and a plurality of thermal sensors each associated with a particular luminaire and in communication with the color manager, the plurality of thermal sensors being less than the plurality of luminaires, the color manager, responsive to the plurality of thermal sensors and the color sensor, being operable to calculate color coordinates for each of the plurality of luminaires.
摘要:
A redundant powering system for a powered device receiving power over communication cabling, the redundant powering system comprising: a redundant power supply comprising a first power sourcing equipment and a second power sourcing equipment; a powered device; communication cabling connecting the redundant power supply to the powered device, the communication cabling comprising a first path connecting the first power sourcing equipment to the powered device and a second path connecting the second power sourcing equipment to the powered device, the first and second paths at least partially being constituted of a single structured cable, the at least one powered device comprising at least one signature impedance, the redundant power supply being operable so that power is operably supplied to the powered device from only one of the first and second power sourcing equipment.
摘要:
Power sourcing equipment providing a plurality of power sources for connection over communication cabling to a single powered device, the power sourcing equipment comprising: a first power source; a second power source; a control circuit; a current sensor adapted to monitor an output current of the first power source, the current sensor being operatively connected to the control circuit; and a voltage regulating means associated with one of the first power source and the second power source, the voltage regulating means being responsive to the control circuit, the control circuit being operative responsive to the monitored output current to operate the voltage regulating means so as to maintain the monitored output current within a pre-determined range.
摘要:
An optical sampling and control element for use with a luminaire exhibiting a cycle and a frame, the optical sampling and control element being constituted of a color sensor in optical communication with the luminaire; and a sampler connected to the outputs of the color sensor, the sampler comprising an integrator arranged to integrate the outputs of the color sensor over a predetermined period less than the frame.
摘要:
A method of controlling the luminance of a luminaire on an individual frame basis, without affecting a slow acting color loop controlling the color temperature of the luminaire, the method comprising: receiving a reference value representative of a target color; receiving a luminance signal defining the luminance of the luminaire per frame; adjusting a modulated signal driving the luminaire directly responsive to the received luminance signal, thereby controlling the luminance of the luminaire per frame; sampling the optical output of the luminaire per frame; comparing a value responsive to the sampled optical output with a value responsive to the received reference value to output a difference signal; and further adjusting the modulated signal driving the luminaire responsive to the compared value so as to reduce the difference signal.