An apparatus includes a light-emitting diode (LED) driver circuit, one or more LEDs of an LED array, and an electronic switching circuit. The LED driver circuit is configured to generate an electric current. The one or more LEDs are electrically connected to the LED driver circuit. The electronic switching circuit is electrically connected to the one or more LEDs and configured to be placed in one of multiple switching configurations. The electronic switching circuit is further configured to direct a portion of the electric current away from the one or more LEDs, such that a remaining portion of the electric current drives the one or more LEDs. The portion of the electric current corresponds to the one of the multiple switching configurations.

A linear regulator (40) supplies a first drive current (I1) to a first light source (24) in a first period in which the first light source (24) is turned on and a second light source (25) is not turned on, and in a second period in which the first light source (24) and the second light source (25) are turned on, and stops the supply of the first drive current (I1) in a third period in which the first light source (24) and the second light source (25) are turned off. A switching regulator (41) supplies a second drive current (I2) to the second light source (25) in the second period, and stops the supply of the second drive current (I2) in the third period.

An LED illumination device for improving anti-surge capability includes a circuit substrate, a bridge rectifier chip, a surge absorber group, a first anti-surge current-limiting chip group, a second anti-surge current-limiting chip group, an LED illuminating group, and an LED current-limiting group. The surge absorber group is disposed on the circuit substrate and electrically connected to the bridge rectifier chip for absorbing a surge voltage. The first anti-surge current-limiting chip group is disposed on the circuit substrate for absorbing a first predetermined surge voltage. The second anti-surge current-limiting chip group is disposed on the circuit substrate for absorbing a second predetermined surge voltage. The LED illuminating group includes a plurality of LED chips disposed on the circuit substrate. The LED current-limiting group is disposed on the circuit substrate for controlling a total harmonic distortion of current (THDi) of the LED illuminating group.

A circuit and a method of operating LED lighting elements are described. The circuit comprises a first and a second LED lighting element (20, 30). In order to provide a circuit and operating method with reduced complexity, a control circuit (50) controls operation of the first LED lighting element in dependence on a light feedback signal L from a light sensitive element (52). The signal L is dependent on light emitted from the second LED lighting element (30). Said first and said second LED lighting element (20, 30) are in series connection and said control circuit (50) is in parallel connection with said first LED lighting element (20); or said first and said second LED lighting element (20, 30) are in parallel connection and said control circuit (50) is in series connection with said first LED lighting element (20).

A light-emitting device, especially for lighting and/or signaling for a motor vehicle, includes at least a first electroluminescent module and a second electroluminescent module energized in series. Each electroluminescent module includes, in parallel: a first branch having a light source having a first direct threshold voltage beyond which the light source is gated on, and a second branch having an element such that the voltage on the terminals of the element is less than the first direct threshold voltage of the light source. A third branch has a timing module able to time a predetermined period and modify, at the end of the predetermined period, an overall impedance of the second branch so that a voltage in the second branch is greater than the first direct threshold voltage of the light source. The predetermined period in the first electroluminescent module is less than that of the second electroluminescent module.

One example described herein includes a light-emitting diode (LED) driver system. The system includes an error amplifier configured to compare an input voltage with a reference voltage to generate a control voltage. The system further includes an amplifier output stage configured to control an output current through a first current path and a shunt current through a second current path based on the control voltage. The amplifier output stage comprises a slew-rate controller configured to control a slew-rate of the shunt current. The shunt current can be provided through a shunt resistor in the second current path and added to the output current to provide a total current through an LED string.

One example described herein includes a light-emitting diode (LED) driver system. The system includes an error amplifier configured to compare an input voltage with a reference voltage to generate a control voltage. The system further includes an amplifier output stage configured to control an output current through a first current path and a shunt current through a second current path based on the control voltage. The amplifier output stage comprises a slew-rate controller configured to control a slew-rate of the shunt current. The shunt current can be provided through a shunt resistor in the second current path and added to the output current to provide a total current through an LED string.

optoelectronic circuit intended to receive a variable voltage containing an alternation of rising and falling phases. The optoelectronic circuit includes light-emitting diodes and a switching device capable of allowing or of interrupting the flowing of a current through each light-emitting diode. Each light-emitting diode is covered with a photoluminescent layer. The photoluminescent layer covering at least one of the light-emitting diodes includes at least one first luminophore having a first decay constant and at least one second luminophore having a second decay constant different from the first decay constant.

optoelectronic circuit intended to receive a variable voltage containing an alternation of rising and falling phases. The optoelectronic circuit includes light-emitting diodes and a switching device capable of allowing or of interrupting the flowing of a current through each light-emitting diode. Each light-emitting diode is covered with a photoluminescent layer. The photoluminescent layer covering at least one of the light-emitting diodes includes at least one first luminophore having a first decay constant and at least one second luminophore having a second decay constant different from the first decay constant.

Provided is an apparatus for supplying power. The apparatus includes a rectifier unit configured to apply a voltage by rectifying alternating current power source, a light emitting unit including a plurality of light emitting diodes which emit light by electric current according to the voltage and are connected in series, a signal generation unit configured to generate a driving signal by dropping the voltage of the rectifier unit, and a switch unit including a plurality of transistors which are connected to the plurality of light emitting diodes, respectively, and are turned on by the driving signal and switch a route of electric current flowing in the plurality of light emitting diodes to be supplied to a microcontroller as power source.