Abstract: AC LED light engines powered directly from the AC power line contain circuitry of resistors, capacitors, diodes and transistors which enables an array of LEDs to efficiently produce light with a relatively low level of flicker as perceived by the human eye. The LEDs are driven by a current which is alternately capacitively-limited and resistively-limited. Capacitively-limited pulses of current are combined with resistively-limited pulses of current so that the resulting output current ripple is at frequencies of 240 Hz or above which the human eye cannot perceive. The combination of resistively-limited current and capacitively-limited current results in a current drain from the power line which is generally sinusoidal and can have a power factor in excess of 0.90, and a flicker index below 0.2.

Abstract: AC LED light engines powered directly from the AC power line contain circuitry of resistors, capacitors, diodes and transistors which enables a single string LEDs connected to series to efficiently produce light with a relatively low level of flicker as perceived by the human eye. The LEDs are driven by a current which is alternately capacitively-limited and resistively-limited. Capacitively-limited pulses of current are interposed between resistively-limited pulses of current so that the resulting output current ripple is at frequencies of 240 Hz or above which the human eye cannot perceive. The combination of resistively-limited current and capacitively-limited current results in a current drain from the power line which is generally sinusoidal and can have a power factor in excess of 0.70.

Abstract: AC LED light engines powered directly from the AC power line contain circuitry of resistors, capacitors, diodes and transistors which enables an array of LEDs to efficiently produce light with a relatively low level of flicker as perceived by the human eye. The LEDs are driven by a current which is alternately capacitively limited and resistively-limited. Capacitively-limited pulses of current are combined with resistively-limited pulses of current so that the resulting output current ripple is at frequencies of 240 Hz or above which the human eye cannot perceive. The combination of resistively-limited current and capacitively-limited current results in a current drain from the power line which is generally sinusoidal and can have a power factor in excess of 0.90, and a flicker index below 0.2.

Abstract: AC LED light engines powered directly from the AC power line contain circuitry of resistors, capacitors, diodes and transistors which enables a single string LEDs connected to series to efficiently produce light with a relatively low level of flicker as perceived by the human eye. The LEDs are driven by a current which is alternately capacitively-limited and resistively-limited. Capacitively-limited pulses of current are interposed between resistively-limited pulses of current so that the resulting output current ripple is at frequencies of 240 Hz or above which the human eye cannot perceive. The combination of resistively-limited current and capacitively-limited current results in a current drain from the power line which is generally sinusoidal and can have a power factor in excess of 0.70.

Abstract: AC LED light engines powered directly from the AC power line contain circuitry of resistors, capacitors, diodes and transistors which enables a single string LEDs connected to series to efficiently produce light with a relatively low level of flicker as perceived by the human eye. The LEDs are driven by a current which is alternately capacitively-limited and resistively-limited. Capacitively-limited pulses of current are interposed between resistively-limited pulses of current so that the resulting output current ripple is at frequencies of 240 Hz or above which the human eye cannot perceive. The combination of resistively-limited current and capacitively-limited current results in a current drain from the power line which is generally sinusoidal and can have a power factor in excess of 0.70.

Abstract: AC LED light engines powered directly from the AC power line contain circuitry of resistors, capacitors, diodes and transistors which enables an array of LEDs to efficiently produce light with a relatively low level of flicker as perceived by the human eye. The LEDs are driven by a current which is alternately capacitively limited and resistively-limited. Capacitively-limited pulses of current are combined with resistively-limited pulses of current so that the resulting output current ripple is at frequencies of 240 Hz or above which the human eye cannot perceive. The combination of resistively-limited current and capacitively-limited current results in a current drain from the power line which is generally sinusoidal and can have a power factor in excess of 0.90, and a flicker index below 0.2.

Abstract: The present invention relates to providing an improved dimming driver circuitry, system and a method thereof. The dimming driver circuitry is configured to enable dimming intensity of light generated by one or more light sources, the dimming driver circuitry being connected to a dimmer that provides to it an alternating current (AC) signal. The dimming driver circuitry may in some examples not include a processing unit. Additionally or alternatively, the dimming driver circuitry may in some examples apply amplitude modulation to the output current provided to the one or more light sources. In some of these examples, the dimming driver circuitry may begin to apply at substantially the same time pulse width modulation and amplitude modulation to the output current provided to the one or more light sources.

Abstract: AC LED light engines powered directly from the AC power line contain circuitry of resistors, capacitors, diodes and transistors which enables a single string LEDs connected to series to efficiently produce light with a relatively low level of flicker as perceived by the human eye. The LEDs are driven by a current which is alternately capacitively-limited and resistively-limited. Capacitively-limited pulses of current are interposed between resistively-limited pulses of current so that the resulting output current ripple is at frequencies of 240 Hz or above which the human eye cannot perceive. The combination of resistively-limited current and capacitively-limited current results in a current drain from the power line which is generally sinusoidal and can have a power factor in excess of 0.70.

Abstract: A circuit serving as a power source for light-emitting diode (LED) lighting applications, the circuit comprising a boost converter comprising a pair of boost field-effect transistors (FETs) and a boost inductor coupled to the pair of boost FETs, wherein an input voltage feeding the boost converter has a sinusoidal waveform, and wherein a half cycle of the input voltage is represented by a plurality of time slices, and a controller coupled to the boost converter and configured to determine a current time slice in the plurality of time slices, generate one or more output signals based at least in part on the current time slice and without a need to compute any multiplier function involving the input voltage, and control states of the boost FETs using the one or more output signals.

Abstract: Methods and apparatus are described that can provide improved power factor correction and total harmonic distortion, efficiency and/or direct feedback of load current variations to a power source inverter. In one example, a power supply, for example, a ballast, can have an input circuit, an output circuit and an inverter circuit coupled between the input circuit and the output circuit. A current feedback circuit is coupled between the output circuit and the inverter circuit and configured to feed current back to the inverter circuit through a transformer stage separate from the inverter as a function of a current level in the output circuit.

Abstract: Methods and apparatus are described that can provide improved power factor correction and total harmonic distortion, efficiency and/or direct feedback of load current variations to a power source inverter. In one example, a power supply, for example, a ballast, can have an input circuit, an output circuit and an inverter circuit coupled between the input circuit and the output circuit. A current feedback circuit is coupled between the output circuit and the inverter circuit and configured to feed current back to the inverter circuit through a transformer stage separate from the inverter as a function of a current level in the output circuit.

Abstract: A circuit serving as a power source for light-emitting diode (LED) lighting applications, the circuit comprising a boost converter comprising a pair of boost field-effect transistors (FETs) and a boost inductor coupled to the pair of boost FETs, wherein an input voltage feeding the boost converter has a sinusoidal waveform, and wherein a half cycle of the input voltage is represented by a plurality of time slices, and a controller coupled to the boost converter and configured to determine a current time slice in the plurality of time slices, generate one or more output signals based at least in part on the current time slice and without a need to compute any multiplier function involving the input voltage, and control states of the boost FETs using the one or more output signals.

Abstract: The present invention relates to providing an improved phase controlled dimming LED driver circuitry, system and a method thereof, which is configured to enable dimming intensity of light generated by a light source, said phase controlled dimming driver circuitry being connected to a phase control dimmer that provides to it a regulated alternating current (AC) signal, wherein said phase controlled dimming driver circuitry does not include a microprocessor and pulse width modulates its output current, provided to said light source, at a frequency unrelated to the AC signal frequency. Further, the phase controlled dimming driver circuitry applies amplitude modulation (AM) and pulse width modulation (PWM) substantially simultaneously to the output current provided to the light source.

Abstract: Circuits are disclosed, for example for driving fluorescent lamps, and such circuits may form part of a ballast. First and second sensing circuits can apply respective signals to a control circuit as a function of an end-of-lamp life condition and of the number of re-strike attempts.

Abstract: Methods and apparatus are described that can provide improved power factor correction and total harmonic distortion, efficiency and/or direct feedback of load current variations to a power source inverter. In one example, a power supply, for example, a ballast, can have an input circuit, an output circuit and an inverter circuit coupled between the input circuit and the output circuit. A current feedback circuit is coupled between the output circuit and the inverter circuit and configured to feed current back to the inverter circuit through a transformer stage separate from the inverter as a function of a current level in the output circuit.

Abstract: An LED light source drive includes an LED current generating circuit and an LED drive controller. The current generating circuit is operable to receive power from a power source and to generate a dc current that can be used to the drive an LED light source. The drive controller is operable to control the dc current to ensure that the light output of the light source remains approximately constant over its operating lifetime. In one embodiment, the drive controller ensures that the effective light output of the light source remains approximately constant by automatically increasing the dc current in predetermined amounts at predetermined times. In an alternative embodiment, the drive controller includes an LED light sensor that is operable to generate a light signal indicative of the effective light output of the light source and the controller uses this light signal to control the dc current output.

Abstract: A ballast for a low pressure gas discharge lamp, preferably of the heated-filament type, includes an on-off indicator for a lamp. The ballast includes a load circuit with a lamp, and a driver for supplying AC load current to the lamp. Such driver includes circuitry for shutting off the load current in the presence of a lamp fault condition. The ballast also includes a pair of nodes having voltage across them when the lamp operates normally, and having substantially no voltage across them when the lamp is off. An on-off lamp indicator circuit includes a light-emitting device and is coupled to the pair of nodes for causing the light-emitting device to emit light when the driver supplies load current to the lamp and for causing the light-emitting device to cease to emit light when the driver no longer supplies load current to the lamp.

Abstract: A ballast for a low pressure gas discharge lamp, preferably of the heated-filament type, includes an on-off indicator for a lamp. The ballast includes a load circuit with a lamp, and a driver for supplying AC load current to the lamp. Such driver includes circuitry for shutting off the load current in the presence of a lamp fault condition. The ballast also includes a pair of nodes having voltage across them when the lamp operates normally, and having substantially no voltage across them when the lamp is off. An on-off lamp indicator circuit includes a light-emitting device and is coupled to the pair of nodes for causing the light-emitting device to emit light when the driver supplies load current to the lamp and for causing the light-emitting device to cease to emit light when the driver no longer supplies load current to the lamp.

Abstract: Gas discharge lamps having filaments at each end thereof are operated in groups according to the power applied to separate line inputs to the ballast. The filaments of the lamps in a first group are powered by a first inverter that provides lamp current to a second group. The filaments of the lamps in the second group are powered by a second inverter that provides lamp current to the first group of lamps. Thus, even if an inverter is turned off, the lamps powered by that inverter are in a pre-heated state for instant starting. Power is coupled to the filaments by a network that is relatively insensitive to changes in frequency.

Abstract: A ballast for a fluorescent lamp incorporates in an integrated circuit (IC) complex circuit functions, such as driving a switching arrangement that provides AC power to the lamp. Beneficially, such IC's may be widely available and inexpensive. Additional circuitry complements such IC by protecting against one or more of the following three conditions: (1) the lamp starting to significantly rectify current in either direction, (2) the lamp voltage exceeding a predetermined level for a prolonged duration, and (3) the power mains supply voltage falling below a predetermined level.