Discharge lamp driving
First Claim
1. A discharge lamp driving circuit comprisingDC voltage input connections,lamp driving connections,bridge circuitry connected to the DC voltage input connections and to the lamp driving connections and including circuit elements which in one mode of operation deliver a higher frequency AC voltage to the lamp driving connections and in another mode of operation deliver a lower frequency AC voltage to the lamp driving connections, andcontrol circuitry connected to control the bridge circuitry selectively as eithera half-bridge to deliver the higher frequency AC voltage to the lamp driving connections during starting ora full-bridge to deliver only the lower frequency AC operating voltage to the lamp while the lamp is operating normally after starting.
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Accused Products
Abstract
A discharge lamp driving circuit includes DC voltage input connections, lamp driving connections, bridge circuitry, and control circuitry. The bridge circuitry is connected to the DC voltage input connections and to the lamp driving connections and includes circuit elements which in one mode of operation deliver a higher frequency AC voltage to the lamp driving connections and in another mode of operation deliver a lower frequency AC voltage to the lamp driving connections. The control circuitry is connected to control the bridge circuitry selectively as either a half-bridge to deliver the higher frequency AC voltage to the lamp driving connections during starting or a full-bridge to deliver only the lower frequency AC operating voltage to the lamp while the lamp is operating normally after starting. A low frequency driver and a high frequency driver are connected to drive the bridge circuitry.
196 Citations
23 Claims
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1. A discharge lamp driving circuit comprising
DC voltage input connections, lamp driving connections, bridge circuitry connected to the DC voltage input connections and to the lamp driving connections and including circuit elements which in one mode of operation deliver a higher frequency AC voltage to the lamp driving connections and in another mode of operation deliver a lower frequency AC voltage to the lamp driving connections, and control circuitry connected to control the bridge circuitry selectively as either a half-bridge to deliver the higher frequency AC voltage to the lamp driving connections during starting or a full-bridge to deliver only the lower frequency AC operating voltage to the lamp while the lamp is operating normally after starting.
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2. A discharge lamp driving circuit comprising
DC voltage input connections, lamp driving connections, bridge circuitry connected to the DC voltage input connections and to the lamp driving connections, and including a low frequency driver and a high frequency driver connected to drive the bridge circuitry so that in one mode of operation a higher frequency AC voltage is delivered to the lamp driving connections and in another mode of operation a lower frequency AC voltage is delivered to the lamp driving connections, and control circuitry connected to control the bridge circuitry to deliver the higher frequency AC voltage to the lamp driving connections during starting or only the lower frequency AC operating voltage to the lamp while the lamp is operating normally after starting.
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17. A method of driving a discharge lamp comprising
operating a bridge circuit as a half bridge to deliver a higher frequency AC voltage from bridge circuitry to the lamp during starting, and operating the bridge circuit as a full-bridge to deliver only lower frequency AC operating voltage from the bridge circuitry to the lamp during normal operation after starting.
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23. A discharge lamp driving circuit comprising
DC voltage input connections, lamp driving connections, and bridge circuitry connected to the DC voltage input connections and to the lamp driving connections and including circuit elements which in one mode of operation deliver a higher frequency AC voltage to the lamp driving connections and in another mode of operation deliver a lower frequency AC voltage to the lamp driving connections, the bridge circuitry including four unidirectional conducting portions connected in a bridge configuration, a low frequency driver, a high frequency driver connected to drive one-half of the bridge, a resonant circuit having an inductor and a capacitor, the inductor being connected to one of the lamp driving connections, and control circuitry connected to control the bridge circuitry to deliver the higher frequency AC voltage to the lamp driving connections during starting and to deliver only the lower frequency AC operating voltage to the lamp while the lamp is operating normally after starting.
Specification