Abstract: A control circuit for controlling the operation of an electrical lighting device, such as a gas discharge ballast or an incandescent lamp, and which can replace a standard switch and requires connection only to the hot wire of an AC power line. The control circuit has a switch encoder which couples two opposite polarity thyristors between the hot wire of an AC power line and the hot wire running through the wall to the fixture. The thyristors are controlled by switches such that the AC waveform is transmitted over the power wires either with the small zero crossing step delays inherent in thyristor switching, or with a chopped waveform such that the transmitted AC waveform has positive going zero crossing step delays or negative going zero crossing step delays. The transmitted AC power waveform is used to power the electrical lighting device as well as to control the operation of the electrical lighting device by connection to a decoder.

Abstract: A universal ballast control circuit allows a universal ballast to accommodate a gas discharge lamp within a relatively wide wattage range using a low-speed microcontroller. The control circuit drives the ballast to start, run and dim a particular lamp type by providing a control voltage signal to a conventional inverter MOSFET driver to effect dynamic and selective changes in the duty cycle and the frequency of the inverter signal. In one aspect of the invention, the control circuit comprises a generator for generating a periodic analog voltage signal, a source for producing a DC voltage signal, a controller which includes a low-speed microcontroller for varying the frequency of the periodic analog voltage signal and the magnitude of the DC voltage signal, and a comparator for comparing the periodic analog voltage signal and the DC voltage signal to produce a control voltage signal.

Abstract: A programmable universal ballast can be programmed to accommodate a gas discharge lamp within a relatively wide wattage range. The ballast uses a microprocessor to store and execute various routines to start, run and dim a particular lamp type. A host computer produces customized routines which are downloaded into a microprocessor located within the ballast. These routines output signals to the MOSFET transistors of the inverter which effect dynamic and selective changes in the duty cycle and the frequency of the inverter signal. By selectively changing simultaneously both the frequency and duty cycle of the inverter signal, the energy spectrum of the resonance network is altered and circuit voltages and currents can be controlled to accurately match required lamp characteristics and operational requirements. The ballast may include an inductive element in parallel with the lamp allowing dimming to 1% of full light output.

Abstract: A power factor correction circuit for use with a power supply. The power supply has an input for receiving an AC input signal, a rectifier for producing a rectified AC signal and an output stage for outputting a DC output signal for driving a load coupled to the output stage. The power factor correction circuit comprises an input port coupled to the rectifier for receiving the rectified AC signal; and an inductor coupled to the input port for storing energy in response to excitation by the rectified AC signal. The excitation of the inductor is controlled through the opening and closing of a switch by a controller. A capacitor is coupled to the inductor and charged by the energy stored in the inductor when the switch is opened to produce the DC output signal. The power factor correction circuit includes a diode for blocking the charge path between the input port and the capacitor and also allowing the controller to boost the charge level on the capacitor.