Osram Sylvania Inc.

Grigoriy A Trestman

Joseph Parisella

John G Konopka

Qinghong Yu

Richard H Koeppl

David L Bay

Joseph L Parisella

A ballast () for powering one or more gas discharge lamps () comprises an inverter (), an output circuit (), and an arc protection circuit (). Arc protection circuit () monitors an electrical signal within the output circuit (). When an arcing condition occurs at the ballast output connections (), the electrical signal includes a high frequency component having a fundamental frequency that is much greater than the normal operating frequency of the inverter (). In response to the high frequency component exceeding a predetermined threshold, arc protection circuit () disables the inverter () for a predetermined shutdown period. Arc protection circuit () also provides a restart function for periodically attempting to ignite and operate the lamps. Arc protection circuit () is preferably realized using a microcontroller integrated circuit () with associated discrete circuitry, and is especially well-suited for use in ballasts for powering multiple lamps via a current-fed self-oscillating inverter and an isolated parallel resonant output circuit.

Ballast with arc protection circuit

A ballast () for powering at least one gas discharge lamp () from a three-phase AC voltage source () comprises a three-phase rectifier circuit (), a high frequency filter capacitor (), a high frequency inverter (), and a three-phase EMI filter (). Three-phase EMI filter () comprises a common-mode EMI inductor (), a Y-capacitor (), and a plurality of X-capacitors (). Common-mode EMI inductor () comprises three magnetically coupled windings () each of which is, preferably, split into two equal winding sections. Ballast () and three-phase EMI filter () provide substantial cost and performance benefits in comparison with existing approaches.

Three-phase electronic ballast with improved three-phase EMI filter

An electronic ballast () for powering a lamp load comprising an even number of gas discharge lamps () includes an inverter (), an output circuit (), and a protection circuit (). During operation, protection circuit () disables the inverter () in response to an end-of-lamp-life condition that is characterized by a predetermined imbalance in the operating current provided to each of the even number of lamps. Preferably, the output circuit () includes a current-sensing transformer () for detecting the predetermined imbalance, and the protection circuit () includes a silicon-controlled rectifier () for disabling the inverter ().

Ballast with end-of-lamp-life protection circuit

A ballast () for powering at least one gas discharge lamp () from a three-phase AC voltage source () comprises a three-phase rectifier circuit (), a high frequency filter capacitor (), and a high frequency inverter (). Preferably, three-phase rectifier circuit () is implemented by a six-diode bridge, and high frequency filter capacitor () can be realized by a film capacitor or a ceramic capacitor. Ballast () provides a high power factor and low total harmonic distortion without requiring a dedicated power factor correction circuit. Other benefits of ballast () include enhanced efficiency, longer life, and lower inrush current.

Three-phase electronic ballast

A ballast ( &prime;) for powering a plurality of gas discharge lamps ( ) includes a load-adaptable charge pump power factor correction arrangement ( ) for feeding back a high frequency current having a magnitude that is dependent on the number of operating lamps.

Electronic ballast with adaptable charge pump power factor correction

An apparatus and method to implement an electronic ballast for a high intensity discharge lamp having AC lamp current centered at approximately 300 kHz minimizes the ballast cost and utilizes modulation of the lamp current to avoid acoustic resonance. In order to minimize the number of additional components providing the modulation function, the ripple voltage produced by PFC circuit is fed through a capacitor to a FREQUENCY SET input of an inverter controller. The value of the capacitor can be chosen to produce the desired modulation range.

Method and apparatus for modulating HID ballast operating frequency using DC bus ripple voltage

A method of and apparatus for operating a high intensity gas discharge lamp is provided wherein the inverter circuit operates at a controlled frequency such that deleterious effects of the lamp's acoustic resonant frequencies are minimized. The inverter utilizes a transformer output with high leakage inductance. The high leakage inductance provides low loss switching operation and simplified control of lamp current during both ignition and warm-up. High frequency operation as well as judicious component design and specification reduces component count, assembled size and cost of ballast.

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Salem, MA, United States of America

Grigoriy A Trestman