A light emitting diode (LED) circuit is disclosed having an LED having a plurality of current paths. A controller may be included for controlling the LEDs. The LED is connected to a first transistor and a first current sink to drive a constant current through the LED through a first current path. At least one cloning transistor can establish a parallel current path through the LED and parallel to the first current path and is connected such that the constant current in the first current sink is duplicated in the parallel current path.

The print head and light emitting elements, first and second drive circuits, and a control circuit. The light emitting elements and drive circuits are spaced from each other an arrangement pitch. The first drive circuit includes a first capacitor and sets a light emission level for the first light emitting element. The second drive circuit includes a second capacitor and sets a light emission level of the second light emitting element. The control circuit is connected to the first drive circuit by a first wiring and to the second drive circuit by a second wiring and controls voltages across the first and second capacitors individually. A difference between the length of the first wiring and the length of the second wiring is less than the arrangement pitch.

A light-emitting circuit includes first and second light-emitting element strings respectively configured to emit light having a first and second color temperatures; a rectifying circuit configured to rectify a voltage, input by an alternating current (AC) power source, to generate a driving voltage; a string switching circuit configured to select at least one light-emitting element string to be used for light emission from among the first light-emitting element string and the second light-emitting element string; an off/on sensing circuit configured to change a selection of the string switching circuit to change a color temperature of light, which is emitted by the light-emitting circuit, when the AC power source is turned off and then turned on; and a driving circuit configured to turn on, in turn, light-emitting elements in the selected at least one light-emitting element string, according to a change in the driving voltage over time.

A Light Emitting Diode, LED, based lighting device arranged for emitting a particular color of light, wherein said LED based lighting device comprises a power supply unit arranged for providing a Direct Current, DC, bus voltage for powering LEDs, a plurality of parallel cascaded LED channels, wherein each of said LED channels is connected to said bus voltage and comprises at least one colored LED and a switch for activating said corresponding LED channel, a controller arranged for providing control signals to each of said switches in said LED channels for periodically activating said LED channels, wherein each of said control signals has a duty cycle, and wherein said controller is arranged for determining said duty cycles of said control signals based on a received color set point, wherein said controller is further arranged for determining an amount of deficiency in light output of each of said LED channels caused by parasitic effects in said LED based lighting device, by determining instantaneous currents of each channel and comparing said instantaneous currents with expected currents resulting from the determined duty cycles, and for increasing said duty cycles based on said determined amount of deficiency.

Apparatus and methods for providing LED lighting on light tape and light sheet. A controller may provide lighting control data to one or more ICs on a segment of tape or sheet. The lighting control data may include a data packet. The data packet may include an address. The address may correspond to one or more of the ICs. The address may correspond to one or more LEDs on the segment. The address may correspond to one or more LEDs on a light tape. The address may correspond to one or more LEDs on a light sheet. The LEDs corresponding to the address may be controlled by a current regulator or regulators on a single IC. The LEDs corresponding to the address may be controlled by current regulators on different ICs.

Apparatus and methods for providing LED lighting on light tape and light sheet. A controller may provide lighting control data to one or more ICs on a segment of tape or sheet. The lighting control data may include a data packet. The data packet may include an address. The address may correspond to one or more of the ICs. The address may correspond to one or more LEDs on the segment. The address may correspond to one or more LEDs on a light tape. The address may correspond to one or more LEDs on a light sheet. The LEDs corresponding to the address may be controlled by a current regulator or regulators on a single IC. The LEDs corresponding to the address may be controlled by current regulators on different ICs.

Self-identifying solid-state transducer (SST) modules and associated systems and methods are disclosed herein. In several embodiments, for example, an SST system can include a driver and at least one SST module electrically coupled to the driver. Each SST module can include an SST and a sense resistor. The sense resistors of each SST module can have at least substantially similar resistance values. The SSTs of the SST modules can be coupled in parallel across an SST channel to the driver, and the sense resistors of the SST modules can be coupled in parallel across a sense channel to the driver. The driver can be configured to measure a sense resistance across the sense resistors and deliver a current across the SSTs based on the sense resistance.

Self-identifying solid-state transducer (SST) modules and associated systems and methods are disclosed herein. In several embodiments, for example, an SST system can include a driver and at least one SST module electrically coupled to the driver. Each SST module can include an SST and a sense resistor. The sense resistors of each SST module can have at least substantially similar resistance values. The SSTs of the SST modules can be coupled in parallel across an SST channel to the driver, and the sense resistors of the SST modules can be coupled in parallel across a sense channel to the driver. The driver can be configured to measure a sense resistance across the sense resistors and deliver a current across the SSTs based on the sense resistance.

An LED driver that is operable with two different types of power source originally designed for a high-intensity discharge lamp. The LED driver directs current of an input power provided by the power source down a first current path if it is determined that the power source comprises a functional ignitor. The LED driver directs current of an input power provided by the power source down a second current path if it is determined that the 5 power source does not comprise a functional ignitor.

An LED driver that is operable with two different types of power source originally designed for a high-intensity discharge lamp. The LED driver directs current of an input power provided by the power source down a first current path if it is determined that the power source comprises a functional ignitor. The LED driver directs current of an input power provided by the power source down a second current path if it is determined that the 5 power source does not comprise a functional ignitor.