Abstract: A load-switch voltage control circuit includes a power control circuit for controlling a switching element that stabilizes the voltage to a load. The power control circuit determines intervals of conduction for the switching element, that connects a control impedance to the load, for stabilizing the voltage across the load.

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 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 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 power management circuit includes first and second power control circuits for controlling respective first and second switching elements that energize a load. The power control circuits determine intervals of conduction for the switching elements that define the voltage charging level of the circuit.

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: A resonant circuit includes a global feedback path from a load to diode elements and an LC notch filter at an input terminal to block energy from the feedback signal going back out on the line. The LC notch filter is tuned to about the frequency of the feedback signal.

Abstract: A ballast circuit includes an output isolation transformer having a primary winding and first and second secondary terminals coupled to opposing ballast lamp terminals for additively applying potentials on the primary winding and the first and second secondary winding potentials across the lamp and limiting ground fault voltages. The circuit can include a closed loop feedback path from a load to a feedback rectifier for promoting linear operation of an input rectifier.

Abstract: A resonant circuit includes a global feedback path from a load to diode elements and an LC notch filter at an input terminal to block energy from the feedback signal going back out on the line. The LC notch filter is tuned to about the frequency of the feedback signal.

Abstract: A power management circuit includes first and second power control circuits for controlling respective first and second switching elements that energize a load. The power control circuits determine intervals of conduction for the switching elements that define the voltage charging level of the circuit.

Abstract: A ballast circuit includes an output isolation transformer having a primary winding and first and second secondary terminals coupled to opposing ballast lamp terminals for additively applying potentials on the primary winding and the first and second secondary winding potentials across the lamp and limiting ground fault voltages. The circuit can include a closed loop feedback path from a load to a feedback rectifier for promoting linear operation of an input rectifier.

Abstract: A ballast circuit includes an output isolation transformer having a primary winding and first and second secondary terminals coupled to opposing ballast lamp terminals for additively applying potentials on the primary winding and the first and second secondary winding potentials across the lamp and limiting ground fault voltages. The circuit can include a closed loop feedback path from a load to a feedback rectifier for promoting linear operation of an input rectifier.

Abstract: A ballast circuit includes an output isolation transformer having a primary winding and first and second secondary terminals coupled to opposing ballast lamp terminals for additively applying potentials on the primary winding and the first and second secondary winding potentials across the lamp and limiting ground fault voltages. The circuit can include a closed loop feedback path from a load to a feedback rectifier for promoting linear operation of an input rectifier.

Abstract: The present invention provides a ballast circuit for energizing a load, such as a fluorescent lamp. The ballast circuit can include an inverter circuit that receives a DC voltage across a positive voltage rail and a negative voltage rail, and produces an AC voltage for driving the load. The ballast circuit can further include two inductors coupled in series to one another, and coupled between the inverter and the load to provide a current path between the inverter and the load. A voltage clamping circuit clamps the voltage at the coupling junction between the two inductive elements to a pre-determined positive value during one half cycle of the inverter AC voltage, and to a pre-determined negative value during the other half cycle of the inverter AC voltage.

Abstract: The present invention provides a ballast circuit that allows independent control over a plurity of lamps. In one embodiment, the ballast circuit receives power from two independent AC sources to independently energize two lamps. The ballast circuit includes a rectifier that receives input AC signals from the independent AC sources and applies a DC voltage to an inverter. The inverter in turn can apply an AC voltage to the lamps. The ballast further includes two bias circuits, each of which permits the application of the inverter AC signal to one of the lamps when one input AC signal is present and inhibits the application of the inverter AC signal to that lamp when the input AC signal is not present.

Abstract: A circuit for driving a load. In one embodiment, the load is driven by an inverter circuit having a full bridge circuit divided by inductive elements to provide cross conduction protection. In another embodiment, first and second converter circuits are coupled to the inverter circuit with the inverter and converter circuits having common circuit elements. In a further embodiment, a common mode inducter is inductively coupled to a power circuit for detecting a common mode signal generated by a load current return path disruption. The common mode inductor is coupled to a control circuit for limiting current to the load.

Abstract: An electronic circuit providing independent operation and application of instant start voltages to each of a plurality of lamps. In a first embodiment, a circuit includes inductively coupled first and second inductive elements disposed on a single bobbin. A capacitive element is coupled between the first and second inductive elements to allow the inductively coupled inductive elements to operate independently when a lamp is removed from the circuit. A steady state strike voltage is generated at the lamp terminals from which a lamp has been removed. In another embodiment, a circuit includes a first circuit path including a first inductive element coupled to a first lamp and a second circuit including a second inductive element coupled to a second lamp. The first and second inductive elements are inductively coupled to effectively cancel flux generated while the first and second lamps are energized.

Abstract: A ballast circuit independently energizes first and second lamps. In one embodiment, an inverter provides a drive signal for energizing the first and second lamps. A first signal detection circuit detects a first AC input signal and a second signal detection circuit detects a second AC input signal, each of which energizes a respective one of first and second lamps. A first lamp control circuit receives a signal from the first signal detector such that the first lamp is energized by the drive signal when the first AC input signal is present. Similarly, a second lamp control circuit receives a signal from the second signal detector such that the second lamp is energized by the drive signal when the second AC input signal is present.

Abstract: A ballast includes a hot restart circuit for hot restart of a HID lamp. In one embodiment, the hot restart circuit includes inductively coupled first and second inductive elements coupled end to end. A first capacitor has a first terminal coupled to a point between the first and second inductive elements and a second terminal coupled to a switching element. When the switching element transitions to a conductive state, a voltage pulse is generated on the second inductive element and the corresponding pulse on the first inductive element is sufficient to achieve hot restart of the lamp. In one embodiment, the first capacitor and the second inductive provide a parallel resonant LC circuit. The resultant signal on the second inductive element increases a voltage on the first inductive element for hot restart of the lamp.

Abstract: A ground fault detection circuit is coupled to an AC circuit and to earth ground for detecting a flow of energy from the AC circuit to earth ground through a path external to the AC circuit. In one embodiment, the ground fault circuit includes a detection circuit coupled to a negative rail of an inverter, which forms part of the AC circuit, and a detection control circuit coupled to the inverter for disabling the AC circuit.