A lighting device configured to deactivate pathogens in an environment. The lighting device includes a housing, means for mounting the housing to a surface in the environment, one or more first light-emitting elements arranged in the housing and configured to each produce disinfecting light having a wavelength in a first range of wavelengths, and one or more second light-emitting elements arranged in the housing and configured to each produce disinfecting light having a wavelength in a second range of wavelengths different from the first range of wavelengths. The disinfecting light produced by the first light-emitting elements and the disinfecting light produced by the second light-emitting elements mix to form a combined light, the combined light being visible light other than white light.

An illumination device and methods are provided herein for avoiding over-current and over-power conditions in one or more power converters included within the illumination device. The illumination device may include at least a plurality of light emitting diode (LED) chains, a driver circuit, at least one power converter, and a control circuit. In some embodiments, the control circuit may be generally configured for determining a maximum safe current level and/or a maximum safe power level attributed to the power converter(s) at a present operating temperature, and for adjusting respective drive currents supplied to the plurality of LED chains by the driver circuit, so as not to exceed the maximum safe current level or the maximum safe power level at the present operating temperature. In some embodiments, a temperature sensor may be included within the illumination device for measuring the operating temperature presently associated with the power converter(s).

The invention relates to a light device for a motor vehicle, comprising a matrix light source having a matrix of elementary light sources with an electroluminescent semiconductor element. Each elementary light source has an emitting surface that is less than or equal to 0.2 mm2. The measures proposed by the invention allow such a matrix light source to be powered without any risk of damage due to overheating of the semiconductive junctions of the elementary light sources that make up the light source.

An LED driving device includes a DC/DC controller which controls an output stage for supplying an output voltage to an LED; and a current driver which generates an output current of the LED. The current driver performs PWM dimming by turning on the output current in accordance with an LED-current-on period of a PWM dimming signal and turning off the output current in accordance with an LED-current-off period of the PWM dimming signal. The DC/DC controller includes a feedback control unit which performs feedback control for outputting a switching pulse to the output stage so as to make a cathode voltage of the LED equal to a reference voltage. A pulse addition control unit performs pulse addition control for adding a predetermined pulse number of additional switching pulses at a time of switching between the LED-current-on period and the LED-current-off period.

An LED driving device includes a DC/DC controller which controls an output stage for supplying an output voltage to an LED; and a current driver which generates an output current of the LED. The current driver performs PWM dimming by turning on the output current in accordance with an LED-current-on period of a PWM dimming signal and turning off the output current in accordance with an LED-current-off period of the PWM dimming signal. The DC/DC controller includes a feedback control unit which performs feedback control for outputting a switching pulse to the output stage so as to make a cathode voltage of the LED equal to a reference voltage. A pulse addition control unit performs pulse addition control for adding a predetermined pulse number of additional switching pulses at a time of switching between the LED-current-on period and the LED-current-off period.

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.

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.

A LED controller for an LED pixel array includes a serial interface to an external data bus, along with an address generator connected to the serial interface and the LED pixel array. An image frame buffer is connected to the interface to receive image data and further connected to the address generator to receive an image frame buffer address. A command and control module is connected to the serial interface and configured to modify image frame buffer output signals. A calibration data storage module is connected to the command and control module to store calibration data related to pixel voltage response in the LED pixel array and enable modification of voltage provided by the dynamic power supply at least in part based on the image presented by the LED pixel array.

A brown-out detection apparatus including a voltage sensing circuit, a first circuit, and a second circuit. The voltage sensing circuit senses an input AC voltage having a first nominal input voltage value or a second nominal input voltage value. The voltage sensing circuit includes an output outputting a reference DC voltage proportional said input AC voltage. The first circuit is responsive to said output of said voltage sensing circuit. The first circuit includes a first output outputting a first voltage value when said input AC voltage is below a threshold voltage level and a second voltage value when said input AC voltage is above said threshold level. The second circuit is responsive to said first output. The second circuit includes a second output outputting a second control signal indicative of a brown-out condition of said input AC voltage.

A brown-out detection apparatus including a voltage sensing circuit, a first circuit, and a second circuit. The voltage sensing circuit senses an input AC voltage having a first nominal input voltage value or a second nominal input voltage value. The voltage sensing circuit includes an output outputting a reference DC voltage proportional said input AC voltage. The first circuit is responsive to said output of said voltage sensing circuit. The first circuit includes a first output outputting a first voltage value when said input AC voltage is below a threshold voltage level and a second voltage value when said input AC voltage is above said threshold level. The second circuit is responsive to said first output. The second circuit includes a second output outputting a second control signal indicative of a brown-out condition of said input AC voltage.