Abstract: A shield around a cathode of a fluorescent lamp, inside the lamp, prevents the overheating of the glass wall of the lamp, in the proximity of the cathode and the premature of the cathode due to the parasitic leakage current to ground.

Abstract: A resonant circuit includes a feedback path for a feedback signal extending from a load terminal to an input terminal so that a potential of the load substantially tracks a potential of the input terminals. A resonant circuit extends from a load to a line terminal so that a potential of the load substantially tracks a potential of the line terminals. A resonant circuit includes a split inductor so that when the load increases so does the equivalent resonant inductance.

Abstract: A resonant circuit includes a clamped feedback signal for providing a load current signal envelope that substantially tracks an input signal. With this arrangement, circuit efficiency is enhanced by the linear operation of the circuit.

Abstract: An AC Power and Frequency Apparatus useful for supplying power to an AC receptive load. Said apparatus facilitates said power and frequency control without first converting the AC input to DC and then subsequently converting said DC signal to AC. The elimination of the DC conversion stage beneficially improves the performance of the apparatus in terms of lower Total Harmonic Distortion and higher Power Factor. Additionally, the reliability of the device is significantly enhanced by elimination of the DC storage capacitor common to prior art utilizing a DC conversion stage. The present invention is particularly useful in controlling power delivered to gas discharge lamps and the like. The device accomplishes the AC power control by switching at least one energy storage inductor with an electronically controlled switch.

Abstract: An improved ballast circuit for use with a compact fluorescent lamp includes an EMI filter, a rectifier and voltage amplification stage, an active resonant circuit and power factor correction stage which is connected in parallel to a lamp load. The ballast circuit includes a feedback capacitor which provides a feedback path for a portion of the high frequency current to the rectifier and voltage amplification stage. The feedback capacitor of the improved ballast circuit reduces the non-linear characteristics of the diode, thus providing almost a linear load on the input power supply and therefore achieving an improved power factor, on the order of 0.95 or greater. The improved ballast circuit may also include a dimming stage which works with the active resonant circuit to vary the amount of power that is supplied to the lamp load. The dimming stage does not require the addition of parasitic active stages and thus provides a lamp with high electrical efficiency.

Abstract: An improved ballast circuit for controlling the power delivered to a fluorescent lamp. The present invention uses a complex resonating circuit to dynamically adjust the power being delivered to the load. The present invention also operates in burst mode allowing an increased voltage to be applied across the lamp load without overstressing the circuit. The increased voltage will light both lamps nearing the end-of-life and lamps in cold weather.

Abstract: An improved ballast circuit for use with a compact fluorescent lamp includes an EMI filter, a rectifier and a voltage amplification stage, an active resonant circuit, a dimming circuit, and a power factor correction stage which is connected in parallel to a lamp load. In one embodiment, the ballast circuit operates in cooperation with a three way switch to adjust the light output of the lamp to three discrete levels corresponding to each setting of the three way switch. In another embodiment the ballast circuit includes a feedback capacitor which provides a feedback path for a portion of the high frequency current to the rectifier and voltage amplification stage. In still another embodiment, the ballast circuit is configured to accept input from a triac or a SCR device. In all of the embodiments, the dimming circuit works with the active resonant circuit to vary the amount of power that is supplied to the lamp load.

Abstract: An improved ballast circuit for use with a compact fluorescent lamp includes an EMI filter, a rectifier and voltage amplification stage, an active resonant circuit and power factor correction stage which is connected in parallel to a lamp load. The ballast circuit includes a feedback capacitor which provides a feedback path for a portion of the high frequency current to the rectifier and voltage amplification stage. The feedback capacitor of the improved ballast circuit reduces the non-linear characteristics of the diode, thus providing almost a linear load on the input power supply and therefore achieving an improved power factor, on the order of 0.95 or greater. The improved ballast circuit may also include a dimming stage which works with the active resonant circuit to vary the amount of power that is supplied to the lamp load. The dimming stage does not require the addition of parasitic active stages and thus provides a lamp with high electrical efficiency.

Abstract: A compact dimmable fluorescent lamp apparatus that connects with at least one fluorescent lamp and with an input power source that supplies an AC input voltage. The lamp includes a rectification stage for rectifying the AC input voltage, a dimming stage for generating a dimming signal indicative of lamp brightness, and a ballast circuit that is in electrical communication with the rectification stage and the dimming stage. The ballast circuit is arranged for connection with the lamp for applying power variably to the lamp and includes a resonant circuit stage that electrically connects with the lamp and that generates a high frequency voltage in response to the input voltage. The resonant circuit varies the level of power supplied to the lamp in response to the dimming signal, thereby attaining a selected level of lamp brightness.