A method for droop control in a DC system comprising a DC source, a DC bus and at least two DC application devices. Each application device having a droop curve and the DC source providing a DC voltage over the DC bus to each application device. Each application device performs a first voltage measurement during a first load condition and performs a second voltage measurement during a second load condition. Each application device adjusts its respective settings of the droop curve in accordance with the first and second voltage measurements.

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.

Methods and apparatus for implementing a control apparatus for a light fixture for externally controlling the current to the LED light emitter of a landscape LED light fixture. In an exemplary embodiment a control apparatus for controlling current to an LED light source in a landscape lighting device includes an LED driver, a user control with a control setting indicator, and a driver housing including setting indicators.

A load control device for controlling the intensity of a lighting load, such as a light-emitting diode (LED) light source, may include a power converter circuit operable to receive a rectified AC voltage and to generate a DC bus voltage, a load regulation circuit operable to receive the bus voltage and to control the magnitude of a load current conducted through the lighting load, and a control circuit operatively coupled to the load regulation circuit for pulse width modulating or pulse frequency modulating the load current to control the intensity of the lighting load to a target intensity. The control circuit may control the intensity of the lighting load by pulse width modulating the load current when the target intensity is above a predetermined threshold and control the intensity of the lighting load by pulse frequency modulating the load current when the target intensity is below the predetermined threshold.

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.

Methods for controlling temperature in an LED luminaire are disclosed. The LED luminaire has one or more sets of LED light engines disposed on a printed circuit board (PCB), some or all of which are activated in response to an instruction or set of instructions. A temperature of the PCB is measured in at least one location. If the temperature exceeds a threshold, the duty cycle of active sets of LED light engines is ramped down uniformly over time.

The disclosure relates to a device and a circuit for protecting controlled loads, and an apparatus for switching between the loads. The device includes: a plurality of load switches, comprising at least first and second load switches, wherein the first and second load switches are respectively in series connection with first and second controlled loads to form first and second controlled load branches in parallel connection, and each load switch is turned on when a switch control terminal is in a first voltage/current interval and turned off when the switch control terminal is in a second voltage/current interval; and a signal control module, including a signal control element, wherein the signal control element is switched between the switch control terminals of the first and second load switches for connection, and the signal control element enables, when being connected to the switch control terminal, the corresponding switch control terminal to be in the second voltage/current interval, and enables, when being disconnected from the switch control terminal, the corresponding control terminal to be in the first voltage/current interval.

The disclosure relates to a device and a circuit for protecting controlled loads, and an apparatus for switching between the loads. The device includes: a plurality of load switches, comprising at least first and second load switches, wherein the first and second load switches are respectively in series connection with first and second controlled loads to form first and second controlled load branches in parallel connection, and each load switch is turned on when a switch control terminal is in a first voltage/current interval and turned off when the switch control terminal is in a second voltage/current interval; and a signal control module, including a signal control element, wherein the signal control element is switched between the switch control terminals of the first and second load switches for connection, and the signal control element enables, when being connected to the switch control terminal, the corresponding switch control terminal to be in the second voltage/current interval, and enables, when being disconnected from the switch control terminal, the corresponding control terminal to be in the first voltage/current interval.

An LED tube lamp comprises: a glass lamp tube; a light diffusion layer disposed on a surface of the glass lamp tube; an LED light strip, which comprises a fixing portion and an extending portion disposed in the glass lamp tube; a plurality of LED light sources mounted on the fixing portion of the LED light strip; a fixing structure disposed between the fixing portion and the inner circumferential surface the glass lamp tube; a power supply module disposed on the fixing structure and electrically connecting to the LED light strip and two end caps attached to two ends of the glass lamp tube respectively. The fixing structure comprises a first end fixedly connected to the inner circumferential surface of the glass lamp tube and a second end fixedly connected to the fixing portion of the LED light strip and not connected to the extending portion of the LED light strip.

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.