Universal Lighting Technologies, Inc.

Other

Fulham Company Limited

Lightech Electronic Industries Ltd.

Robertson Worldwide, Inc.

Peter W Shackle

Qinghong Yu

John Jay Dernovsek

Christopher Radzinski

Zhanqi Du

Ruhe Shi

Christopher Radzinkski

David Anthony Blair

Zhiqing Wu

Barrie Drew

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.

AC-powered LED light engine

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.

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. Additionally or alternatively, the dimming driver circuitry may in some examples include at least one linear dimming control pin connected to at least one capacitor and/or resistor configured to fine-tune capacitance and/or resistance.

Phase controlled dimming LED driver system and method thereof

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.

Electronic ballasts with high-frequency-current blocking component or positive current feedback

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.

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.

Ballasts for fluorescent lamps

The present invention relates generally to a simple, low cost ballast for fluorescent lamps that incorporates an integrated circuit and a number of ballast protection functions to cost effectively enhance its reliability. End of lamp life circuitry is provided to shut down the ballast when rectification currents due to lamp aging exceed a predetermined level. This circuitry also functions to stop the ballast operation when the lamp's voltage exceeds a predetermined cutoff level for a set period of time. Re-ignition circuitry is provided that restarts the ballast when new lamps are installed without shutting off the ballast. Multiple striking attempt circuitry is provided that initiates a predetermined number of striking attempts such that cold or old lamps are quickly ignited without the introduction of excessive flickering.

IC-based low cost reliable electronic ballast with multiple striking attempts and end of lamp life protection

Electronic ballast power supply/control circuits and methods that can be used to supply starting power to PFC control chips and that can be used to control ballasts so that PFC and inverter power supply circuits supply stable power to control circuitry even when the ballasts are performing advanced ballast functions. The circuits and methods supply starting power more quickly and efficiently than prior art starting circuits and control ballasts by either loading PFC circuits or inverter circuits included in the ballasts. The circuits load PFC circuits by connecting load resistors to the PFC circuits or by operating the inverter circuits at high frequencies that generate switching losses in the inverter transistors that load the PFC circuits. Inverter circuits are loaded by operating the inverter at frequencies that are much higher than preheating, igniting, and normal operating frequencies.

Power supply circuits and methods for supplying stable power to control circuitry in an electronic ballast

An instant-start ballast for a multiple gas discharge lamp fixture has a single half-bridge inverter that is used to drive at least two series resonant output circuits. Each series resonant output circuit is used to drive two gas discharge lamps. A single output voltage limiting circuit is provided with a microprocessor that monitors the combined output voltages of the series resonant output circuits and uses a single voltage limiting transistor to control the output voltages of the circuits. A capacitor is associated with each gas discharge lamp socket in the fixture such that a voltage across the capacitor indicates that a lamp has been installed in the socket associated with the capacitor. The ignition sequence will only be initiated if the capacitor voltages indicate that a lamp has been installed in each socket of a fixture.

High efficiency 4-lamp instant start ballast

An improved high input voltage instant start electronic ballast uses a substantially lossless snubber circuit. The substantially lossless snubber circuit is incorporated into the ballast to reduce turn off losses and increase the efficiency of the ballast. The snubber circuit includes two capacitors connected in parallel with respect to the two switching transistors or FETS in the inverter of the ballast. A series-resonant lamp voltage sensing circuit is also provided that uses a voltage dividing capacitor to accomplish lossless monitoring of the open circuit voltage of the ballast. A cable compensation circuit minimizes variations in the open circuit voltage due to the connecting and disconnecting of a cable to the ballast by limiting the turn on times of the transistors during high voltage conditions.

Electronic ballast with lossless snubber capacitor circuit

An electronic ballast uses a voltage sampling circuit and a voltage control circuit to limit the open circuit voltage of the ballast. A lamp voltage sensing circuit is provided that uses a voltage dividing capacitor to accomplish lossless monitoring of the open circuit voltage of the ballast. A resistor placed in series with the sampling capacitor is used to create a voltage that turns a control transistor off and on. The control transistor produces a gating signal trimming signal that a half bridge driver uses to alter the gating signals provided to the inverter transistors of the ballast. A cable compensation circuit is included that minimizes variations in the open circuit voltage due to the connecting and disconnecting of a cable to the ballast by turning the control transistor off and on.

Electronic ballast with open circuit voltage control and cable compensation

An electronic ballast has a resonant tank circuit that includes a tank inductor and a tank capacitor connected in series. Lossless sampling of the output voltage of the electronic ballast is achieved by monitoring the voltage across a sampling capacitor placed in series with the tank capacitor. A resistive and capacitive filter is used to filter the monitored voltage such that it can be accurately received by a microcontroller. A resistor is connected in series with the sampling capacitor to produce an open circuit output voltage control signal that is used by the microcontroller to limit the open circuit output voltage. A cable compensation circuit is utilized to minimize variations in the open circuit voltage due to the connecting and disconnecting of a cable to the ballast output terminals.

Lossless circuit for sampling of lamp voltage

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.

LED drive for generating constant light output

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.

Growing community of inventors

Rolling Hills Estates, CA, United States of America

Peter W Shackle