THOMAS JON FARKAS, JR
Pilots at Aldersyde Dr, Cleveland, OH

5872429, Feb 16, 1999

Mar 25, 1997

8/824024

Yongping Xia - Torrance CA
Sreeraman Venkitasubrahmanian - Torrance CA
Raj Jayaraman - Rancho Palos Verdes CA
Thomas Farkas - South Euclid OH

Philips Electronics North America Corporation - New York NY

H05B 3702

315194

A communication method particularly suited for lighting control employs encoding of perturbations in a voltage signal having a fundamental period with a nominal waveform. A control period includes a pre-selected number of fundamental periods of the voltage signal. Different control commands are indicated by imposing a selected perturbation, such as a phase cut, on the nominal waveform with a respective occurrence signature within the control period. The control commands are decoded from the voltage signal by detecting the occurrence signature of the perturbations within each control period. Decoding is accomplished by differentiating the nominal waveform to detect encoded perturbations. The technique is particularly suited for two-wire dimming applications for gas discharge lamps, in which the voltage signal carrying the encoded commands is the sinusoidal mains voltage powering the ballast, since the encoded perturbations may be small enough so that lamp flicker is avoided even with encoded signals on the line voltage. In a favorable embodiment for dimming, no perturbations are introduced on the line voltage unless a change in the operating characteristic, for example the light level, of the electric lamp is desired.

5559395, Sep 24, 1996

Mar 31, 1995

8/414859

Sreeraman Venkitasubrahmanian - Torrance CA
Thomas Farkas - South Euclid OH
Raj Jayaraman - Rancho Palos Verdes CA
Yongping Xia - Torrance CA

Philips Electronics North America Corporation - New York NY

H05B 3702

315247

A gas discharge lamp dimming ballast has a two wire input for connection to the hot dimmed and neutral leads of a phase control dimmer. The ballast has an improved topology in which a pre-conditioner supplies a substantially constant DC voltage to a ballast stage including an inverter, a resonant tank output and a control circuit. A dimming interface circuit derives a dimming signal having a voltage equal to the average value of the rectified output voltage of a full-bridge rectifier feeding the pre-conditioner circuit. The dim signal is independent of the DC rail voltage and, in combination with the maintenance of a substantially constant DC rail voltage, permits of improved dimming control while providing the ease of installation of a two wire ballast. The response time of the interface circuit relative to the pre-conditioner is selected to avoid power imbalances. The ballast also includes an EMI filter and circuitry to prevent capacitive hold-up by the EMI filter of the rectified voltage to preserve the conduction angle for the interface circuit.

5691605, Nov 25, 1997

Aug 9, 1995

8/512868

Yongping Xia - Torrance CA
Joshua Zhu - Torrance CA
Sreeraman Venkitasubrahmanian - Torrance CA
Raj Jayaraman - Rancho Palos Verdes CA
Thomas Farkas - South Euclid OH

Philips Electronics North America - New York NY

H02B 3702

315307

A lamp controller includes an interface circuit, or receiver, which receives an input signal and decodes control signals supplied from a transmitting device, such as a power line wall controller, according to at least two of the following communication techniques: phase angle control, step control, and coded control. The receiver tests the input signal and identifies which type of control technique is employed by the wall controller connected to the lamp controller. The receiver then decodes the control command from the input signal. In a disclosed embodiment, the lamp controller is gas discharge lamp dimming ballast having a two wire input for connection to the hot dimmed and neutral leads of the power line controller. The ballast has an improved topology in which a pre-conditioner supplies a substantially constant DC voltage to a ballast stage including an inverter, a resonant tank output and a control circuit. The dim signal output by the receiver is independent of the DC rail voltage and, in combination with the maintenance of a substantially constant DC rail voltage, permits of improved dimming control while providing the ease of installation of a two wire ballast.

5604411, Feb 18, 1997

Mar 31, 1995

8/422198

Sreeraman Venkitasubrahmanian - Torrance CA
Gert W. Bruning - North Tarrytown NY
Paul Veldman - Oss, NL
Thomas Farkas - South Euclid OH
Raj Jayaraman - Rancho Palos Verdes CA
Yongping Xia - Torrance CA

Philips Electronics North America Corporation - New York NY

G05F 100

315307

A dimming ballast for use with a phase control dimmer, and particularly a triac dimmer, includes an EMI filter selected with a high impedance to avoid excessive voltage and peak currents in the filter due to resonance with the phase controlled AC waveform at low conduction angles, when the load presented by the lamp is low. The EMI filter includes a filter capacitor connected at the output of a rectifier. The ballast also includes circuitry to sense the rectified DC voltage and to discharge the filter capacitor when the rectified voltage is at or near zero, to thereby keep the EMI filter loaded and prevent misfiring of the triac dimmer. In a favorable embodiment, the sensing and discharge function is carried out by a pre-conditioner of the switched-mode type.