This disclosure includes systems, methods, and techniques for controlling delivery of power to one or more strings of light-emitting diodes (LEDs). For example, a circuit includes a power converter configured to generate an electrical current, a switching device, and a sensor. The sensor is configured to compare a magnitude of the electrical current to a threshold, and in response to the magnitude exceeding the threshold, cause the switching device to turn on in order to sink a portion of the electrical current to prevent the magnitude of the electrical current from exceeding the threshold. When the switching device is turned on, the electrical current is divided into an undesired electrical current that flows across the switching device and a desired electrical current that flows to the string of LEDs.

A device can include a stand that includes a base and a pole; and a monitoring unit coupled to the pole, where the monitoring unit includes a sensor and a status indicator that changes from an unoccupied illumination to an occupied illumination responsive to detection via the sensor of human presence in a region.

A lighting device power control circuit configured to charge one or more capacitors through the pulsing of an inductor is provided. In one example, a lighting device includes a light source and a power control circuit. The power control circuit comprises an inductor, a power transistor configured to pass an operating current associated with the light source, and one or more capacitors configured to keep the power transistor turned on to pass the operating current. The one or more capacitors are configured to be periodically charged in response to a voltage spike generated across the inductor. Related methods and additional embodiments are also provided.

A lighting relay panel may include lower-cost features or components related to improved safety and reliability. In some cases, the relay panel includes a power supply capable of protecting the panel from high-voltage and high-current transients. A microcontroller may determine a power interruption based on a zero-cross signal received from the power supply, and may also configure latching relays during the interruption. In some implementations, the relay panel includes a relay sense circuit that is capable of receiving actuation signals from multiple relays connected to different phases of a power signal, and the microcontroller may synchronize or repeat the actuations based on a signal from the relay sense circuit. The microcontroller may generate relay addresses based on the relay positions within the relay panel. In some cases, the relay panel may include isolation circuits that are capable of providing an isolated control signal having an improved voltage range.

A lighting relay panel may include lower-cost features or components related to improved safety and reliability. In some cases, the relay panel includes a power supply capable of protecting the panel from high-voltage and high-current transients. A microcontroller may determine a power interruption based on a zero-cross signal received from the power supply, and may also configure latching relays during the interruption. In some implementations, the relay panel includes a relay sense circuit that is capable of receiving actuation signals from multiple relays connected to different phases of a power signal, and the microcontroller may synchronize or repeat the actuations based on a signal from the relay sense circuit. The microcontroller may generate relay addresses based on the relay positions within the relay panel. In some cases, the relay panel may include isolation circuits that are capable of providing an isolated control signal having an improved voltage range.

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.

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 source device according to an embodiment includes: a first resistor (101) that is connected to a given potential; a light emitting element (12) that is connected in series to the first resistor; a second resistor (102) that is connected to the given potential; and a first current source (104) that is connected in series to the second resistor and that is configured to supply a freely-selected current within a given range are included. A first voltage is taken out from a first connection part where the first resistor and the light emitting element are connected to each other and a second voltage is taken out from a second connection part where the second resistor and the first current source are connected to each other.

A light source device according to an embodiment includes: a first resistor (101) that is connected to a given potential; a light emitting element (12) that is connected in series to the first resistor; a second resistor (102) that is connected to the given potential; and a first current source (104) that is connected in series to the second resistor and that is configured to supply a freely-selected current within a given range are included. A first voltage is taken out from a first connection part where the first resistor and the light emitting element are connected to each other and a second voltage is taken out from a second connection part where the second resistor and the first current source are connected to each other.

An enhanced smart lighting system (ESLS) for use in buildings without neutral wire connections for wall switches. The ESLS entails both a no-neutral wire smart lighting switch (NNWSLS) and a physically separate load adapter. The NNWSLS includes a sensing, control, or communication system (SSCCS) such as integrated WiFi. The load adapter mitigates electrical fluctuations which may be induced in a power load (for example a lightbulb) by the smart lighting switch, particularly when the smart lighting switch is nominally powered off but still has some current flow. The load adapter is an intermediary between the power load and a conventional load receptacle. The load adapter has an integrated dummy load configured in parallel with the power load. The dummy load provides an electrical pathway for low levels of electricity which run through the light socket even when the NNWSLS is set to an “off” configuration.