Abstract: An electronic ballast is provided, which includes first and second output nodes, first and second lamp outputs, and a lamp interface network. The lamp interface network includes an LC circuit coupled between at least one of the first and second output nodes and a respective one of the first and second lamp outputs.

Abstract: An electronic ballast is provided, which includes an energy hold-up circuit that maintains operation of an AC discharge load, such as a gas discharge lamp, during at least a portion of a utility source outage.

Abstract: An embodiment of the present invention pertains to a multiple discharge load electronic ballast system, including a distribution bus and a plurality of electronic ballasts. The distribution bus has a nominal distribution power rating. The plurality of electronic ballasts are operatively coupled to the distribution bus. A respective electronic ballast comprises adaptations for DC voltage control and an alternating current (AC) output, and has a maximum ballast power rating. A sum of the maximum ballast power ratings of the plurality of electronic ballasts is greater than the nominal distribution power rating of the distribution bus.

Abstract: An embodiment of the present invention pertains to a multiple discharge load electronic ballast system, including a distribution bus and a plurality of electronic ballasts. The distribution bus has a nominal distribution power rating. The plurality of electronic ballasts are operatively coupled to the distribution bus. A respective electronic ballast comprises adaptations for DC voltage control and an alternating current (AC) output, and has a maximum ballast power rating. A sum of the maximum ballast power ratings of the plurality of electronic ballasts is greater than the nominal distribution power rating of the distribution bus.

Abstract: A lamp power measurement circuit measures average power delivered to a gas discharge lamp. The circuit includes a voltage sensor having a first measurement output representative of AC voltage across the lamp and a current sensor having a second measurement output representative of AC current through the lamp. A first absolute value circuit is coupled in series with the first measurement output and has a first absolute value output. A second absolute value circuit is coupled in series with the second measurement output and has a second absolute value output. A pulse width modulator modulates one of the first and second absolute value outputs with the other of the first and second absolute value outputs and has a pulse width modulated output. A low-pass filter is coupled in series with the pulse width modulated output and has a DC voltage output representative of average power dissipated through the lamp.

Abstract: A gas discharge lamp control circuit includes a series circuit formed by first and second AC input terminals, an inductance and first and second lamp terminals. An ignitor circuit is coupled to the series circuit and selectively couples and decouples at least a portion of the inductance in parallel with the first and second AC input terminals to generate a flyback voltage in the inductance.

Abstract: A phase control circuit according to the present invention is configured for connection between and AC source and an AC load. The AC source supplies an AC drive signal having a plurality of sequential positive and negative half cycles. The phase control circuit comprises first and second power switches coupled between the AC source and the AC load. The first power switch conducts current of the AC drive signal after a first phase delay during the positive half cycles. The second power switch conducts current of the AC drive signal after a second phase delay during the negative half cycles. A feedback balance circuit is coupled between the AC load and the first and second power switches. The feedback balance circuit determines a DC current component in the AC load and generates a phase delay correction signal as a function of the DC current component.

Abstract: A control circuit for a gas discharge lamp according to the present invention includes a transformer having a primary run winding, a primary start winding and a secondary winding. The primary run winding is coupled to a source of an AC run signal. The secondary winding is coupled to the gas discharge lamp. A current sensor is coupled in series with the gas discharge lamp to sense current flow through the lamp. A high frequency oscillator is coupled to the primary start winding for providing a high frequency start signal to the primary start winding. In a start phase, the oscillator provides the high frequency start signal to the primary start winding to initiate ionization of the gas discharge lamp. Once the gas has sufficiently ionized in the lamp, the control circuit switches from the start phase to a run phase by removing the high frequency start signal from the primary start winding and applying the AC run signal to the primary run winding.