General Electric Company

Melvin C Cosby, Jr

Louis Robert Nerone

Laszlo Sandor Ilyes

David Joseph Kachmarik

In an instant start ballast, dimming control is provided over a range of operation in which lamps driven by the ballast do not require external cathode heating. An interface circuit () includes a winding () that is inductively coupled to windings () of an inverter circuit (). The interface circuit () also includes a variable impedance in parallel with the winding () where the variable impedance includes a transistor () and a Zener diode (). By varying an input voltage across control leads (), the apparent inductance of the winding () is varied. This variance affects the switching frequency of the inverter circuit () affecting the frequency of a drive signal provided to the lamps. Thus the instant start ballast can be dimmed without use of multiple ballasts and/or external cathode heating.

Dimmable instant start ballast

The embodiment disclosed herein relates to a lighting system that includes an auxiliary lighting circuit for use with an electronic HID ballast. The lighting system comprises a power supply configured to provide power to a high intensity discharge (HID) lamp via an electronic ballast and a ballast power sensing component configured to determine the amount of power drawn by the electronic ballast and to convert this power drawn by the electronic ballast to a scaled voltage that is representative of the power drawn by an HID ballast. A lamp driver component is configured to provide power to an auxiliary lamp via the same power supply when the scaled voltage reaches a triggering threshold. A voltage regulation component is configured to regulate the power delivered to the auxiliary lamp such that the auxiliary lamp power stays within a predefined range.

Auxiliary lighting circuit for high intensity discharge system

Auxilary lighting circuit for high intensity discharge system

An inverter circuit for ballasting a gas discharge lamp having a delay circuit designed to delay regenerative control of the inverter switches until a d.c. bus has attained steady-state operating d.c. voltage. The inverter circuit includes a drive control circuit for inducing an a.c. load current. The inverter circuit includes first and second complementary switches serially connected between the bus and a reference bus. The switches are connected together at a common node through which the a.c. load current flows. A driving inductor is connected at one end to the common node and operatively connected at the remaining end to a control node. A load circuit includes a resonant inductor connected at one end to the common node, with the resonant inductor mutually coupled to the driving inductor. A resonant capacitor is serially connected between the remaining end of the resonant inductor and the reference bus. The gas discharge lamp is serially connected with a d.c. blocking capacitor across the resonant capacitor. A delay circuit, comprising a serially connected resistor and capacitor is connected across the drive control circuit.

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Grand River, OH, United States of America

Melvin C Cosby, Jr