An LED light fixture includes a housing, a controller circuit having direct current (DC) and alternating-current (AC) power inputs, a direct-current (DC) power supply unit (PSU) connected to the controller circuit, an alternating-current (AC) PSU connected to the controller circuit, and at least two groups of light emitting diodes (LEDs) operable to emit light, wherein each group includes at least one LED of a first type and at least one LED of a second type. In some embodiments, when the LED light fixture operates in a security mode the controller prevents power from flowing to the AC PSU and allows power to flow to the DC PSU to power only the first type of LEDs of the at least two groups of LEDs to emit a security light.

An LED tube lamp having an LED unit is disclosed. The LED tube lamp includes a control circuit that selectively determines whether to perform a first mode or a second mode of lighting operation according to a state of a property of an external driving signal and a switching circuit coupled to the control circuit and the LED unit. When the control circuit determines to perform the first mode of lighting operation, the control circuit controls the second circuit in a manner such that the switching circuit maintains its on state to allow continual current to flow through the LED unit, until the external driving signal is disconnected from the LED tube lamp, and when the control circuit determines to perform the second mode of lighting operation, the control circuit controls the switching circuit in a manner to regulate the continuity of current to flow through the LED unit by alternately turning on and off the switching circuit.

Provided is an audio reproduction device including: a light source provided in the vicinity of a speaker unit; a detection unit that detects a beat of an audio signal reproduced by the speaker, and outputs a detection signal corresponding to the beat; and a light emission control signal output unit that controls a light emission mode of the light source in accordance with the detection signal, and outputs a light emission control signal for allowing generation of white light for a short period at a peak of intensity of the light source.

An LED driver circuit and a method prevent LED turn-off flash when input power is lost to the driver circuit. The driver circuit includes a DC-DC converter that provides an LED drive voltage to an LED load. A voltage drop sensing circuit detects the loss of input power and discharges a filter capacitor that provides operating power to a controller in a DC-DC converter. The controller turns off to halt the operation of the DC-DC converter before the voltage provided to the LED load decreases to a turn-off threshold of the LED load. The DC-DC converter cannot recharge a load capacitor across the LED load. Thus, once the LEDs in the LED load turn off, the LEDs remain off until the input power is restored.

A laser sensor stimulator integrates laser units, an inertial measurement unit, a control unit, and ergonomic, modular design with GPS data feeds into a portable system that can be used to test energy sensors and warning devices and includes a user interface facilitates tracking and acquisition of items of interest by the laser sensor stimulator.

The semiconductor light source drive device according to the present disclosure includes: a switching power source that is connected in series with a semiconductor light source element and a constant current circuit to output a predetermined voltage to the semiconductor light source element and the constant current circuit; a detection circuit that detects a voltage at a connecting point between the semiconductor light source element and the constant current circuit; and a controller that controls the voltage output from the switching power source based on the voltage detected by the detection circuit, and controls a current value of the constant current circuit based on a switching signal. The controller, prior to varying the current value of the constant current circuit, varies the voltage output from the switching power source in accordance with an amount to be varied in the current value of the constant current circuit.

In one example, a system includes a load module, a voltage module, and a controller. The load module is configured to selectively bypass each load unit of a plurality of load units to form a series string of load units. The voltage module is configured to output a voltage across the series string of load units that is based on a target voltage. The controller is configured to output an indication of the target voltage, estimate a time delay for switching one or more load units of the plurality of load units, and output, after outputting the indication of the target voltage for the time delay, a control signal to switch one or more load units of the plurality of load units such that the series string of load units has the target quantity of load units.

To provide an illumination device that has light emitting diodes as light sources and is capable of switching emission colors and of performing dimming in each of the emission colors, an illumination device includes plural light emitting units in which at least one light emitting diode is disposed, the other light emitting units than the light emitting unit whose forward voltage is a maximum are provided with a switching element that is connected in series with the light emitting diode, and the other light emitting units than the light emitting unit whose forward voltage is a minimum are provided with an element that is connected in series with the light emitting diode and has a resistance.

Power receptacle control circuitry includes load switching circuitry, communications circuitry, sensor circuitry, processing circuitry, and a memory. The sensor circuitry includes a light sensor. The processing circuitry is coupled to the load switching circuitry, the communications circuitry, the sensor circuitry, and the memory. The memory includes instructions, which, when executed by the processing circuitry cause the power receptacle control circuitry to selectively deliver power to a load via the load switching circuitry, detect a modulated light signal via the light sensor, and join a group of devices based on the modulated light signal.

A load control device (e.g., an LED driver) for controlling the intensity of a lighting load (e.g., an LED light source) may provide a wide output range and flicker-free adjustment of the intensity of the lighting load. The load control device may comprise a load regulation circuit, a control circuit, and a filter circuit (e.g., a boxcar filter circuit) that operates in a different manner in dependence upon a target current. When the intensity of the lighting load is near a low-end intensity, the control circuit may adjust an operating frequency of the load regulation circuit in response to the target current, and may control the filter circuit to filter a current feedback signal during a filter window that repeats on periodic basis. When the intensity of the lighting load is near a high-end intensity, the control circuit may control the filter circuit to constantly filter the current feedback signal.