Integral crystal-controlled line-voltage ballast for compact RF fluorescent lamps
First Claim
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1. A ballast circuit for a fluorescent lamp comprising:
- a rectifier-filter means adapted for coupling to an AC power source to generate a DC voltage,an oscillator circuit coupled to said DC voltage for developing an RF oscillator signal,switching signal generating means response to said oscillator signal to develop concurrent oppositely phased switching signals at the frequency of said oscillator signal,series connected power transistors having inputs coupled to said switching signals, said transistors having a common output, a fluorescent lamp energization coil coupled to said common output,said switching signal generating means including feedback means for regeneratively feeding back a portion of the current in said coil to aid in switching said power transistors whereby said transistors develop an RF power output signal at said common output to drive said coil, said power output signal being in the form of a square wave, anda filter circuit coupled intermediate said common output and said coil to transform said square wave to a sinusoidal wave.
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Abstract
A ballast circuit for a fluorescent lamp including a rectifier-filter for coupling to an AC power supply to generate a DC voltage, an oscillator circuit coupled to said DC voltage for developing an RF oscillator signal, and switching signal means for developing concurrent oppositely phased switching signals at the frequency of said oscillator signal to drive series connected power transistors. The common output of the power transistors is coupled to energize a fluorescent lamp coil and regenerative feedback means for generating a signal to aid in switching the power transistors.
33 Citations
19 Claims
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1. A ballast circuit for a fluorescent lamp comprising:
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a rectifier-filter means adapted for coupling to an AC power source to generate a DC voltage, an oscillator circuit coupled to said DC voltage for developing an RF oscillator signal, switching signal generating means response to said oscillator signal to develop concurrent oppositely phased switching signals at the frequency of said oscillator signal, series connected power transistors having inputs coupled to said switching signals, said transistors having a common output, a fluorescent lamp energization coil coupled to said common output, said switching signal generating means including feedback means for regeneratively feeding back a portion of the current in said coil to aid in switching said power transistors whereby said transistors develop an RF power output signal at said common output to drive said coil, said power output signal being in the form of a square wave, and a filter circuit coupled intermediate said common output and said coil to transform said square wave to a sinusoidal wave. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A ballast circuit for a fluorescent lamp comprising:
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rectifier-filter means adapted for coupling to an AC power source to generate a DC voltage, an oscillator circuit coupled to said DC voltage for developing an RF oscillator signal, said oscillator circuit including a resonant circuit tuned to the frequency of said oscillator circuit, switching signal generating means including a portion of said resonant circuit responsive to said oscillator signal to develop concurrent oppositely phased switching signals at the frequency of said oscillator signal, series connected power transistors, each of said transistors having a separate input, said transistors having a common output, means for coupling said switching signals to said separate inputs of said transistors to develop an RF power output signal at said common output, said power output signal being in the form of a square wave, a fluorescent lamp energization coil driven by said RF output signal, and, a filter circuit coupled intermediate said common output and said coil to transform said square wave to a sinusoidal wave. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18, 19)
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Specification