A light emitting device array comprises a plurality of light emitting diode (LED) strings connected in parallel to each other, each of which includes a plurality of light emitting devices connected in series. A sum of forward voltages (Vf) of a plurality of light emitting devices included in at least one LED string among the plurality of LED strings is less than that of forward voltages of a plurality of light emitting devices included in a different LED string. The at least one LED string includes a voltage compensation unit, to compensate for a difference in forward voltage levels between the at least one LED string and the different LED string.

An optoelectronic circuit for receiving a variable voltage containing alternating increasing and decreasing phases, the optoelectronic circuit including a plurality of groups of light-emitting diodes and a switching device for allowing or interrupting the circulation of a current through each group, the switching device also being suitable for detecting whether said variable voltage is supplied by a dimmer.

An electronic driver circuit for LEDs and LASERs is provided for use in time-of-flight applications featuring a high efficiency of energy-conversion and a high precision of distance-measurements based on a dual conversion circuit. A voltage to voltage DC-DC conversion is hereby merged with a DC-voltage to pulsed-current booster, this booster operating at a time-of-flight modulation frequency. At the start of a new measurement cycle, the PWM signal for driving the DC-DC conversion is updated in response to currents observed during previous illumination periods.

According to the present invention, provided is an LED driving circuit comprising: a first rectification module, connected to an alternating current power source, for full-wave rectifying an applied alternating current voltage and for supplying a first rectification voltage which has been full-wave rectified to an LED light emitting module as a first driving voltage; and a second driving voltage supply module, connected to the alternating current power source in parallel with the first rectification module, for full-wave rectifying an applied alternating current voltage to generate a second rectification voltage, for charging energy using the generated second rectification voltage at a charging section, and for supplying a second driving voltage to the LED light emitting module at a compensating section.

A lighting unit includes a power supply that provides a maximum voltage and multiple LED lighting circuits. Each of the LED lighting circuits includes an LED string, multiple switches, a switching sequencer and a switch controller. The LED string includes multiple series-connected emitters having a total forward voltage that exceeds the maximum voltage of the power supply. Each of the switches is coupled in parallel with a respective LED of the LED string. The switching sequencer provides a sequence of switching patterns such that a total forward voltage of simultaneously active LEDs in each switching pattern does not exceed the maximum voltage of the power supply. The switch controller actuates switches according to each of the switching patterns in the sequence. The LED string of each of the plurality of LED lighting circuits is arranged in a two-dimensional array.

A lighting unit includes a power supply that provides a maximum voltage and multiple LED lighting circuits. Each of the LED lighting circuits includes an LED string, multiple switches, a switching sequencer and a switch controller. The LED string includes multiple series-connected emitters having a total forward voltage that exceeds the maximum voltage of the power supply. Each of the switches is coupled in parallel with a respective LED of the LED string. The switching sequencer provides a sequence of switching patterns such that a total forward voltage of simultaneously active LEDs in each switching pattern does not exceed the maximum voltage of the power supply. The switch controller actuates switches according to each of the switching patterns in the sequence. The LED string of each of the plurality of LED lighting circuits is arranged in a two-dimensional array.

An LED device with energy compensation includes a first LED driving circuit, a second LED driving circuit, and a capacitor. The first LED driving circuit includes a first LED driver and a plurality of first LED groups controlled by the first LED driver. The second LED driving circuit including a second LED driver and a plurality of second LED groups controlled by the second LED driver. The second LED driving circuit is connected in parallel with the first LED driving circuit. The capacitor has a first terminal coupled to the second LED driving circuit and a second terminal coupled to one of the first LED driving circuit and the second LED driver. A power source is coupled to the first LED driving circuit, the second LED driving circuit, and the first terminal of the capacitor for applying an AC power to the first terminal of the capacitor.

A device is configured to determine a switching pattern comprising a first time range for activating a first plurality of light emitting diodes (LEDs) of a LED module and a second time range for activating a second plurality of LEDs of the LED module. The first plurality of LEDs and the second plurality of LEDs are different. The device is further configured to determine, for each LED of the first plurality of LEDs, a respective timeslot of a plurality of timeslots of the first time range. The device is further configured to output an instruction to a switching device to cause the switching device to couple each LED of the first plurality of LEDs to a supply during the respective timeslot determined for the LED.

A light system is disclosed. The light system includes a light emitting diode (LED) and a shunt transistor having a current path connected to the LED. A ramp generator circuit generates a ramp voltage. An amplifier has a first input terminal connected to the LED, a second input terminal coupled to receive the ramp voltage, and an output terminal connected to a control terminal of the shunt transistor.

An apparatus for auto addressing includes a communication bus interface configured to receive an address assignment request to assign an address to the apparatus. A functional connection is configured to activate a device connected to the apparatus. A detector is configured to measure a characteristic of the device and to compare the characteristic with a validation parameter. The characteristic depends on the functional connection. An address assignment circuit is configured to store the address in a memory of the apparatus in response to receiving the address assignment request at the apparatus, and the characteristic being validated with the validation parameter.