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 trailer lighting activation system includes a vehicle light sensor, an ambient light sensor, and a microcontroller. The vehicle light sensor is removably attached to a towing vehicle light to detect a light output of the towing vehicle light, and to provide a vehicle light sensor output signal in response to the light output of the towing vehicle light. The ambient light sensor can detect an ambient light level and provide an output signal in response to the ambient light level. The microcontroller is coupled to the vehicle light sensor output and to the ambient light sensor and has an output for energizing a trailer light in response to the ambient light sensor output signal and the vehicle light sensor output signal. An overcurrent monitor is coupled to the trailer light and to monitor current drawn by the trailer lighting activation system.

A trailer lighting activation system includes a vehicle light sensor, an ambient light sensor, and a microcontroller. The vehicle light sensor is removably attached to a towing vehicle light to detect a light output of the towing vehicle light, and to provide a vehicle light sensor output signal in response to the light output of the towing vehicle light. The ambient light sensor can detect an ambient light level and provide an output signal in response to the ambient light level. The microcontroller is coupled to the vehicle light sensor output and to the ambient light sensor and has an output for energizing a trailer light in response to the ambient light sensor output signal and the vehicle light sensor output signal. An overcurrent monitor is coupled to the trailer light and to monitor current drawn by the trailer lighting activation system.

An illumination power circuit with a dimming function and an associated control method thereof are provided, where the illumination power circuit includes a first conversion circuit, a digital controller and a second conversion circuit. The first conversion circuit converts a first analog dimming signal from an analog dimmer into a first digital dimming signal, where the analog dimmer generates the first analog dimming signal according to operations of a user, to allow the user to manually control brightness of an illumination device. The digital controller receives the first digital dimming signal and a control signal from a computer, and generates at least one final dimming signal according to the first digital dimming signal and the control signal. In addition, the second conversion circuit generates a direct current output signal according to the final dimming signal, for driving the illumination device.

An illumination power circuit with a dimming function and an associated control method thereof are provided, where the illumination power circuit includes a first conversion circuit, a digital controller and a second conversion circuit. The first conversion circuit converts a first analog dimming signal from an analog dimmer into a first digital dimming signal, where the analog dimmer generates the first analog dimming signal according to operations of a user, to allow the user to manually control brightness of an illumination device. The digital controller receives the first digital dimming signal and a control signal from a computer, and generates at least one final dimming signal according to the first digital dimming signal and the control signal. In addition, the second conversion circuit generates a direct current output signal according to the final dimming signal, for driving the illumination device.

A load control device for controlling power delivered from an AC power source to an electrical load may have a closed-loop gate drive circuit for controlling a semiconductor switch of a controllably conductive device. The controllably conductive device may be coupled in series between the source and the load. The gate drive circuit may generate a target signal in response to a control circuit. The gate drive circuit may shape the target signal over a period of time and may increase the target signal to a predetermined level after the period of time. The gate drive circuit may receive a feedback signal that indicates a magnitude of a load current conducted through the semiconductor switch. The gate drive circuit may generate a gate control signal in response to the target signal and the feedback signal, and render the semiconductor switch conductive and non-conductive in response to the gate control signal.

A load control device for controlling power delivered from an AC power source to an electrical load may have a closed-loop gate drive circuit for controlling a semiconductor switch of a controllably conductive device. The controllably conductive device may be coupled in series between the source and the load. The gate drive circuit may generate a target signal in response to a control circuit. The gate drive circuit may shape the target signal over a period of time and may increase the target signal to a predetermined level after the period of time. The gate drive circuit may receive a feedback signal that indicates a magnitude of a load current conducted through the semiconductor switch. The gate drive circuit may generate a gate control signal in response to the target signal and the feedback signal, and render the semiconductor switch conductive and non-conductive in response to the gate control signal.

A circuit comprises an optical coupling including an illuminator optically coupled to an optical sensor to output a voltage from the optical sensor based on intensity of illumination from the illuminator. The circuit includes a voltage input node with a resistance connected in series between the voltage input and a Zener diode. A method includes powering an illuminator with current from a first voltage input node. The method includes sensing illumination level in illumination from the illuminator with a sensor and outputting output proportionate to illumination sensed by the sensor indicative of voltage detected at the voltage input node. The method can include limiting current between the voltage input node and the illuminator.

A circuit comprises an optical coupling including an illuminator optically coupled to an optical sensor to output a voltage from the optical sensor based on intensity of illumination from the illuminator. The circuit includes a voltage input node with a resistance connected in series between the voltage input and a Zener diode. A method includes powering an illuminator with current from a first voltage input node. The method includes sensing illumination level in illumination from the illuminator with a sensor and outputting output proportionate to illumination sensed by the sensor indicative of voltage detected at the voltage input node. The method can include limiting current between the voltage input node and the illuminator.

A light-emitting element driving semiconductor integrated circuit that constitutes at least a portion of a light-emitting element driving device configured to drive a plurality of light-emitting elements connected in series includes: a controller configured to have a first mode in which switching control is performed on a transistor connected in series to the plurality of light-emitting elements and a second mode in which linear control is performed on the transistor; and a first detector configured to detect that a current flowing through a sense resistor connected in series to the plurality of light-emitting elements and the transistor reaches a threshold value, wherein the controller switches from the switching control to the linear control based on an output of the first detector.