Abstract: A system and method of controlling power to a high-intensity-discharge lamp is provided. A voltage sensor determines voltage across the lamp. A current sensor determines current through the lamp. A control circuit approximates lamp power based on input from the sensors, compares the lamp power against a desired level, and regulates lamp power based on the comparison.

Abstract: A system and method of controlling power to a high-intensity-discharge lamp is provided. A voltage sensor determines voltage across the lamp. A current sensor determines current through the lamp. A control circuit approximates lamp power based on input from the sensors, compares the lamp power against a desired level, and regulates lamp power based on the comparison.

Abstract: A printed circuit board assembly comprises a printed circuit board and a heat sink that has two surface planes. One surface plane of the heat sink is raised, and provides a surface area for contact with the printed circuit board. The other surface plane is lower than the raised surface plane. The printed circuit board extends over the lower surface plane. The distance between the raised surface plane and the lower surface plane provides space for through-hole pins that extend beneath the printed circuit board, because the underside of the printed circuit board lies on the raised surface plane. The multi-plane heat sink can be formed by an extrusion process, as well as a stamping or other process that allows for more complex patterns of surfaces.

Abstract: A ballast for powering a high intensity discharge lamp including an ignitor and a resonant circuit. Ignition pulses produced by the ignitor are added to a boosted low frequency voltage produced by the circuit operating near its resonant frequency during start up of the lamp. The circuit is disabled after a predetermined period of time has elapsed following ignition of the lamp. Application of the signal precedes application of the ignitor pulses to the lamp. Disablement of the circuit can render the ignitor inoperable.

Abstract: A lamp driving circuit having a series inductor and capacitor (L-C) in which the lamp load is connected in parallel with the capacitor. During pre-ignition of the lamp load, the driving signal supplied by a half-bridge oscillator includes a fundamental frequency and higher odd harmonics including a third harmonic of the fundamental frequency. The resonant frequency of the series connected L-C circuit is at least .sqroot.5 times greater than the fundamental frequency but not equal to the higher odd harmonic frequencies, preferably less than the third harmonic of the driving signal.

Abstract: An electronic ballast for powering at least two rapid start, parallel connected fluorescent lamps. Associated with each lamp is a serially connected choke and capacitor combination. A train of pulses of alternating polarity having a fundamental frequency, which is generated by an inverter, is applied to each serially connected combination. Each combination is characterized by a resonant frequency which is other than an odd harmonic of and at least two times and preferably .sqroot. 5 times greater than the fundamental frequency. Reduction in filament heating, following lamp ignition, is provided through the addition of voltages applied to each filament which are substantially out of phase with each other.

Abstract: A lamp driving circuit having a series inductor and capacitor (L-C) in which the lamp load is connected in parallel with the capacitor. During pre-ignition of the lamp load, the driving signal supplied by a half-bridge oscillator includes a fundamental frequency and a third harmonic of the fundamental frequency. The resonant frequency of the series connected L-C circuit is at least .sqroot.5 times greater than the fundamental frequency but less than the third harmonic of the driving signal.

Abstract: An electronic high frequency supply, such as a lamp ballast, having a full-wave rectifier, a storage capacitor charged to a voltage greater than the peak of the rectifier output, and an isolating diode between the rectifier and the diode. An inverter is connected to the energy storage capacitor, and has a high frequency inductive load circuit connected between the inverter output and a junction between the isolating diode and the storage capacitor. A capacitor, connected to the junction in parallel with a series circuit formed by the isolating diode and storage capacitor, forms a high frequency resonance circuit with the inductive load circuit. Current is drawn from the rectifier only as a series of pulses at the inverter frequency. To minimize variation in the high frequency load current, the inverter frequency is varied according to a sensed parameter which varies during each cycle of the rectifier output.

Abstract: An electronic ballast which will repeatedly try to ignite gas discharge lamps should they fail to ignite under conditions in which they should have ignited together with means rendering said electronic ballast incapable of trying to ignite said lamps after a predetermined period and said electronic ballast being rendered capable of again trying to ignite said lamps under prescribed conditions.

Abstract: Apparatus for starting and operating a high pressure discharge lamp includes a pair of input terms for connection to a high frequency inverter. A step-up transformer couples the input terminals to a pair of output terminals for connection of the discharge lamp. A switching arrangement including a voltage-multiplier circuit, is coupled to the primary winding of the transformer and includes a first branch comprising a first capacitor and a diode and a second branch comprising a diode. Between the first capacitor and the diode of the first branch is connected a third branch comprising a semiconductor switch such as a SIDAC. The first branch is connected through the transformer coil to a first supply source connection point. The second branch is connected to a tap point of the coil. The first and the second branch are connected via a common impedance including second capacitor and an inductor to a second supply source connection point.