A lighting driver includes a processor configured to generate a compensator signal based on a first signal during a constant current mode and based on a second signal during a constant voltage mode. The first signal corresponds to a current through an LED light source coupled to an output of the driver, and the second signal corresponds to a voltage at the output. The driver further includes a controller to control, based on the compensator signal, an amount of power provided to the LED light source. The driver also includes a constant current source circuit to be coupled to the LED light source. During the constant current mode, a flow of the current through the constant current source circuit is disabled, and, during the constant voltage mode, disabling the flow of the current through the constant current source circuit disables a flow of the current through the LED light source.

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.

Power supplies (1) comprise first induction circuits (11) for receiving first amounts of power from source circuits, second induction circuits (12) for providing second amounts of power to combinations (2) of light circuits (21) and capacitor circuits (22), control circuits (13) for controlling the second amounts, and trigger circuits (14) for bringing the control circuits (13) into first modes having first durations equal to time-intervals. The control circuits (13) in the first modes guide supplying current signals for supplying the combinations (2) and subsequently discharging current signals for reducing charges of the capacitor circuits (22) and in second modes prevent the flowing of the discharging current signals. The light circuits (21) experience low output levels without experiencing low frequency ripples. The control circuits (3) may comprise parallel combinations of transistors (15) such as field effect transistors and diodes (16) such as parasitic-reverse-diodes of the field effect transistors. The first/second modes may be conducting/non-conducting modes of the transistors (15).

Power consumption in a start-up circuit for a LED-based light bulb may be reduced by digitally switching a transistor of the start-up circuit coupled to the input voltage. When the transistor is digitally switched between on and off, a reduced amount of power is dissipated by the transistor, because it may not enter a saturation region of operation where the resistance of the transistor between drain and source terminals increases. The transistor may be coupled to a voltage regulator for generating one or more output voltages, including a supply voltage for a host controller IC. The transistor may be switched on and off by a digital signal generated by logic circuitry, which may decide to switch the transistor on and off based on a voltage level at an output of the voltage regulator.

Illumination systems, flexible lighting apparatus and/or lighting control methods are described herein. In various embodiments, one or more signals indicative of a shape formed by a flexible substrate (104, 204,304, 504, 604) of a flexible lighting apparatus (100, 200, 300, 600) may be obtained from a plurality of sensors (110, 210, 310) associated with the flexible lighting apparatus. One or more lengths of the flexible substrate along the one or more axes may be detected based on the one or more signals provided by the plurality of sensors. One or more LEDs (or more generally, light sources) (102, 202, 302, 502) disposed along the one or more axes of the flexible substrate may be energized to emit light having one or more lighting properties selected based on the detected one or more lengths.

A light source lighting circuit comprises a first lighting circuit for receiving current from the electric power supply line and supplying drive current to a first light source and a second lighting circuit for receiving the current from the electric power supply line and supplying drive current to a second light source. When a state of the drive current flowing to the first light source shows an abnormality, or when state of the drive current flowing to the second light source shows an abnormality, the first lighting circuit stops operation. When a state of the drive current flowing to the second light source shows an abnormality, or when a state of the drive current flowing to the first light source shows an abnormality, the second lighting circuit stops operation.

A lighting device 10 includes light sources 17, a light source board 18, and a casing 13. The light source board 18 includes a board body portion 18a having a substantially circular outer edge where the light sources 17 are arranged at intervals in a substantially annular shape such that each light source 17 emits light toward a center, an extended portion 18b extending inward from the board body portion 18a, and a trace portion 19 electrically connected to each light source 17 and disposed in an area from the board body portion 18a to the extended portion 18b such that an end of the trace portion 19 is arranged at a distal end of the extended portion 18b. The casing 13 includes a tubular-shaped side wall portion 13b surrounding the light sources 17, and a bottom portion 13a disposed opposite the board body portion 18a and having an exit hole 13a1 therethrough through which the extended portion 18b is inserted and the distal end 18b1 of the extended portion 18b is extended outside.

A lamp control device includes a converter configured to provide an output voltage and an internal voltage; a lamp including an LED module which has a plurality of LED channels, and configured to emit light in correspondence to the output voltage of the converter; and a controller configured to operate by using the internal voltage of the converter, control the output voltage of the converter to be retained at a level equal to or higher than a predetermined level, by using feedback voltages of the plurality of LED channels, and control channel currents of the plurality of LED channels to be regulated in correspondence to memory values which are set in advance.

A method for controlling an output of an electrical AC voltage U comprising the following steps: switching on a current flow I induced by the AC voltage as soon as an absolute value of the AC voltage U exceeds a switching-off target voltage, and switching on the current flow I as soon as the absolute value for the AC voltage U falls below a switching on target voltage. The switching-off target voltage and the switching-on target voltage are defined as positive and the switching-on target voltage is lower than or equal to the switching-off target voltage. The method according to the invention serves to dim an LED lamp in a brightness range of 0% to 100% of a maximum brightness of the LED lamp.

An ac-dc power supply includes a dc-dc converter coupled to an input of the ac-dc power supply. The input of the ac-dc power supply is coupled to receive an ac input voltage and an ac input current. The dc-dc converter includes a regulated output and a reservoir output. A controller is coupled to receive sense signals from the dc-dc converter. The controller is coupled to control the dc-dc converter to regulate the regulated output in response to the sense signals. The controller is further coupled to control a waveform of the ac input current to have a substantially same shape as a waveform of the ac input voltage. A regulator circuit is coupled to the regulated output and the reservoir output. The controller is coupled to the regulator circuit to control a transfer of energy from the reservoir output to the regulated output through the regulator circuit.