A short protecting circuit for a LED (Light-emitting Diode) driver for powering a plurality of LED strings, having: a short comparing circuit, configured to provide a plurality of short fault indicating signals; a first logic circuit, configured to provide a short fault signal based on the plurality of short fault indicating signals to indicate a short fault condition; a timing circuit, configured to provide a short protecting enable signal; and a second logic circuit, configured to provide a plurality of short isolating signals; wherein the short isolating signals are blocked when an open fault signal is valid.

An emergency LED lighting system maintains power to an LED lighting source based on measured voltages and currents provided to the LED lighting source; rolls back or decreases power provided to an LED lighting source over time in order to increase the amount of time the battery can power the LED lighting source; executes a soft start procedure, such that the power provided to the LED lighting source is gradually ramped up during activation of the LED lighting sources; identifies a type of battery coupled to the emergency LED lighting system; cycles the emergency LED lighting system between charging mode and standby mode to reduce power consumption over a window of time; detects AC power or an absence of AC power; and/or uses a status LED to communicate information about the emergency LED lighting system with a remote device.

Programmable drivers (or power supplies) for solid state light sources are disclosed, on which output regulation is improved to expand the dimming range to 1% and reduce and/or remove flicker. Additional fault conditions are set up to avoid latching, and thus provide for a controllable restart feature. Such drivers include an isolated half bridge resonant converter with an improved control approach designed to regulate very low current though primary side in a feed-forward loop. Such drivers include both digital and analog loops that improve the performance in steady state and/or during transients, particularly for a lighting load, in comparison to a single full digital control.

LED related lighting methods and apparatus are described. Various features relate to water tight light fixtures. Some of the fixtures are spotlights while other fixture are intended for in ground use. The light fixtures in at least some embodiments include power control features. In spotlight embodiments beam angle and power or light output can be controlled without opening the light assembly or compromising the water tight seals which also protect against dirt. In ground embodiments support tilt angle setting which allow a user to set the light fixture to one or more tilt angles. Beam angle can also be changed in some embodiments as well as power control. Beam angle, power control and tilt angle adjustments are supported in some embodiments but need not be supported in all embodiments with some embodiments using one or more of the described features but not all features.

A disconnect component coupled between a lighting load and a main power line. The disconnect component includes an input coupled to the main power line and a neutral line input to the disconnect component from the 277 volt circuit and an output coupled to the lighting load. The disconnect component includes a monitor that monitors a voltage on the main power line and a coupling component that couples the main power line to the output. The coupling component is configured to decouple the main power line from the output when the monitor senses a voltage on the main power line is higher than an upper limit voltage and re-couple the main power line to the output when the monitor senses that the voltage on the main power line is below the upper limit voltage.

An illumination device and method is provided herein for calibrating individual LEDs in the illumination device, so as to obtain a desired luminous flux and a desired chromaticity of the device over changes in drive current, temperature, and over time as the LEDs age. The calibration method may include subjecting the illumination device to a first ambient temperature, successively applying at least three different drive currents to a first LED to produce illumination at three or more different levels of brightness, obtaining a plurality of optical measurements from the illumination produced by the first LED at each of the at least three different drive currents, obtaining a plurality of electrical measurements from the photodetector and storing results of the obtaining steps within the illumination device to calibrate the first LED at the first ambient temperature. The plurality of optical measurements may generally include luminous flux and chromaticity, the plurality of electrical measurements may generally include induced photocurrents and forward voltages, and the calibration method steps may be repeated for each LED included within the illumination device and upon subjecting the illumination device to a second ambient temperature.

A system (100) for protection of solid state electrical devices against over and/or under voltage conditions, comprises an AC input (110), supplying an AC connected with fuse, AC filters (112), connected with the AC input (110) via the fuse, configured to filter the AC, rectifiers (114), connected with the AC filters (112), configured to convert the AC line voltage into DC line voltage thereby forming a DC bus voltage, buck converters (118), connected with the rectifiers (114), configured to step down the DC bus voltage thereby providing a first DC voltage, voltage dividers (116), connected with the rectifiers (114), configured to divide the DC bus voltage, thereby generating a second DC voltage, a threshold detector (120) connected with the buck converters (118) and the voltage dividers (116), a relay (122) connected with the threshold detector (120), the AC input (110) supplying the AC and one or more loads (124).

A device for supplying electric power to an electronic component, including a DC-to-DC converter able to operate using pulse width modulation with high states and low states, with an input and an output, the output being intended to supply power to the electrical component; and a protective circuit connected to the input of the DC-to-DC converter, with a storage capacitive component connected to a diode for protecting against polarity reversals. The protective circuit furthermore includes a bypass for bypassing the protective diode so as to allow the storage capacitive component to discharge during the low states of the pulse width modulation.

LED related lighting methods and apparatus are described. Various features relate to water tight light fixtures. Some of the fixtures are spotlights while other fixture are intended for in ground use. The light fixtures in at least some embodiments include power control features. In spotlight embodiments beam angle and power or light output can be controlled without opening the light assembly or compromising the water tight seals which also protect against dirt. In ground embodiments support tilt angle setting which allow a user to set the light fixture to one or more tilt angles. Beam angle can also be changed in some embodiments as well as power control. Beam angle, power control and tilt angle adjustments are supported in some embodiments but need not be supported in all embodiments with some embodiments using one or more of the described features but not all features.

A light-emitting diode (LED) tube lamp adapted to install on a lamp socket and configured to emit light when receiving an external driving signal without the external driving signal passing through or being output from a ballast includes a lamp tube, two end caps, each having at least one external connection terminal, a rectifying circuit, for rectifying the external driving signal to produce a rectified signal; a filtering circuit, for filtering the rectified signal to produce a filtered signal; an LED module, disposed on a power loop of the LED tube lamp, coupled to the filtering circuit, and configured for emitting light; a driving circuit coupled between the rectifying circuit and the LED module, and configured to drive the LED module; a mode determination circuit coupled to the rectifying circuit and the driving circuit and configured to detect the voltage level of the rectified signal; a switch circuit; and an installation detection circuit coupled to the mode determination circuit, the switch circuit, and the rectifying circuit; and configured to detect an installation state between the LED tube lamp and a lamp socket based on the voltage level of the rectified signal detected by the mode determination circuit.