Abstract: A lighting circuit (A) includes an input (10), which supplies a single switch ballast (12), which in turn powers a lamp (14). Ballast (12) is in a self-starting, self-oscillating class E converter configuration, which allows for adjustment of the switching duty ratio. Self-oscillation occurs due to the use of regenerative feedback path consisting of a first winding (36), feedback inductor (40), and charging capacitor 42. Increasing output to MOSFET switch (34) occurs once MOSFET switch (34) has been biased to an on state through inputs from input circuit (12), which have been supplied from current source (32). Adjustment of the switching ratio for MOSFET switch (34) is accomplished by selection of appropriate values for zener diodes (48, 50), wherein the voltage breakdown of the zener diode 50 is greater than zener diode 48 reduce the duty ratio to less than 50%, thereby reducing the voltage rating of the switch.

Abstract: A ballast circuit 10 for a gas discharge lamp 14, incorporates a shutdown circuit 12 for limiting voltage output of a d.c.-to-a.c. converter 21. The shutdown circuit includes a pair of terminals 66 and 68 connecting across an inductor 48 in order to sense the inductive voltage of the d.c.-to-a.c. converter 21. A rectifier network 70-76 receives the inductor voltage and generates a full-wave rectified voltage. A latch 84 is arranged to receive the rectified voltage and to enter an active state when the rectified voltage is above a pre-determined value. A time delay circuit 118 located between the rectifier network 70-76 and the latch 84 provides an adjustable delay time prior to activation of the latch network. Upon activation of the latch, the inductor voltage is decreased and the ballast circuit 10 is taken out of resonance thereby lowering the voltage and current applied to the resonant circuit 28.

Abstract: A ballast circuit for a gas discharge lamp includes a d.c.-to-a.c. converter circuit with circuitry for coupling to a resonant load circuit, for inducing a.c. current therein. The converter circuit comprises a pair of switches serially connected between a bus conductor at a d.c. voltage and a reference conductor, the voltage between a reference node and a control node of each switch determining the conduction state of the associated switch. The respective reference nodes of said switches are connected together at a common node through which said a.c. current flows, and the respective control nodes of the switches are connected together. A gate drive arrangement is provided for regeneratively controlling the first and second switches.

Abstract: A ballast circuit for a gas discharge lamp includes a d.c.-to-a.c. converter circuit with circuitry for coupling to a load circuit, for inducing a.c. current therein. The converter circuit comprises a pair of switches serially connected between a bus conductor at a d.c. voltage and a reference conductor. The voltage between a reference node and a control node of each switch determines the conduction state of the associated switch. The respective reference nodes of the switches are connected together at a common node through which the a.c. current flows, and the respective control nodes of the switches are connected together. The load circuit has circuitry for connecting to a gas discharge lamp and comprises a piezoelectric transformer having a body and including a reference lead connected to one of the bus and reference conductors, an input lead coupled to the common node, and an output lead connected to the lamp.

Abstract: A ballast circuit for a gas discharge lamp with high speed gate drive circuitry comprises a resonant load circuit including a resonant inductance, a resonant capacitance, and circuitry for connecting to a gas discharge lamp. A d.c.-to-a.c. converter circuit induces a.c. current in the load circuit, and comprises a pair of switches serially connected between a bus conductor at a d.c. voltage and a reference conductor, the voltage between a reference node and a control node of each switch determining the conduction state of the associated switch. The reference nodes of the switches are connected together at a common node through which the a.c. current flows, and the control nodes of the switches are connected together. A gate drive arrangement for regeneratively controlling the switches comprises a driving inductor connected between the common node and the control nodes and mutually coupled to an inductor in the load circuit for sensing current in the circuit.

Abstract: A ballast circuit for a gas discharge lamp includes a rectifier coupled to convert current from an a.c. source to d.c. current provided on bus and reference conductors. A smoothing capacitance, coupled between the bus and reference conductors, smooths current supplied by the rectifier. A resonant load circuit includes a resonant inductance, a resonant capacitance, and means to connect to the lamp. A d.c.-to-a.c. converter circuit, coupled to the resonant load circuit, induces an a.c. current in the resonant load circuit. The converter circuit comprises first and second switches serially connected between the bus and reference conductors, and being connected together at a common node through which the a.c. load current flows. The switches each comprise a reference node and a control node, the voltage between such nodes determining the conduction state of the associated switch. The respective reference nodes of the switches are interconnected at the common node.

Abstract: Disclosed is an integrated circuit for use in a ballast circuit for supplying a.c. current to a resonant load circuit incorporating a gas discharge lamp and a resonant inductance and capacitance. The integrated circuit comprises a d.c.-to-a.c. converter circuit comprising first and second switches serially connected between a bus pin, for connection to a bus conductor at a d.c. voltage, and a reference pin, for connection to a reference conductor. The switches are connected together at a node connected to a common pin through which the a.c. current flows, have respective control nodes connected to a control pin, and have respective reference nodes. The voltage between the control pin and an associated reference node determines the conduction state of the associated switch. A first embodiment also includes first and second resistors serially connected between the bus and reference pins, with their intermediate node connected to an intermediate pin.

Abstract: A dimmable ballast circuit for a gas discharge lamp comprises a resonant load circuit with a resonant inductance, a resonant capacitance and circuitry for connecting to a gas discharge lamp. A d.c.-to-a.c. converter circuit is coupled to the resonant load circuit for inducing a.c. current therein, and comprises a pair of switches serially connected between a bus conductor at a d.c. voltage and a reference conductor. The voltage between a reference node and a control node of each switch determines the conduction state of the associated switch. The respective reference nodes of the switches are interconnected at a common node through which the a.c. current flows, and the respective control nodes of the switches are substantially directly interconnected. A gate drive arrangement for regeneratively controlling the switches comprises a driving inductor connected between the common node and the control nodes and mutually coupled to the resonant inductor for sensing current therein.

Abstract: A ballast circuit for a gas discharge lamp comprises a resonant load circuit incorporating the gas discharge lamp and including a resonant inductance and a resonant capacitance. A d.c.-to-a.c. converter circuit induces an a.c. current in the resonant load circuit. The converter circuit comprises first and second switches serially connected between a bus conductor at a d.c. voltage and a reference conductor, and which are connected together at a common node through which the a.c. load current flows. A voltage-breakover (VBO) device is effectively connected between the common node and a second node. A network is provided for setting the voltage of the second node with respect to the common node at less than the breakover voltage of the VBO device when the lamp is operating at steady state. A polarity-determining impedance is connected between the common node and one of the bus conductor and the reference conductor, to set the initial polarity of pulse to be generated upon the firing of the VBO device.

Abstract: A power supply circuit for powering a load circuit comprises a load circuit and includes a converter circuit for inducing current in the load circuit. The converter circuit comprises first and second converter switches serially connected in the foregoing order between a bus conductor at a d.c. voltage and a reference conductor, and connected together at a common node through which the load current flows. The first and second converter switches each comprise respective interconnected control nodes and references connected together at the common node. The voltage between a control node and associated reference node determines the conduction state of the associated switch. A first node is coupled to the bus conductor, and a second node is coupled to the reference conductor. A bridge network is connected between the first and second nodes and has first and second input nodes on which respective first and second input signals are applied.

Abstract: A circuit with a small package for MOSFETs comprises a load circuit in which an a.c. current flows. Further included are a p-channel enhancement-mode MOSFET and an n-channel enhancement-mode MOSFET, the sources of which are connected together at a common node through which the a.c. current flows. The MOSFETs respectively provide positive-going and negative-going contributions to the a.c. current, with approximately equal r.m.s. values. A package is provided in which the MOSFETs are arranged adjacent to each other, in the same plane. A main surface of the package has an area of no more than about 40.5 square millimeters. The channel area of the p-channel MOSFET is from about 1.4 to about 2.0 times the channel area of the n-channel MOSFET.

Abstract: A ballast circuit for a gas discharge lamp comprises a resonant load circuit including the lamp. A d.c.-to-a.c. converter circuit induces an a.c. current in the resonant load circuit. The converter circuit comprises first and second switches serially connected between a bus conductor at a d.c. voltage and a reference conductor, and being connected together at a common node through which the a.c. load current flows. The first and second switches each comprise a reference node and a control node, the voltage between such nodes determining the conduction state of the associated switch. The respective reference nodes of the first and second switches are interconnected at the common node. The respective control nodes of the first and second switches are interconnected. An inductance is connected between the control nodes and the common node. A starting pulse-supplying capacitance is connected in series with the inductance, between the control nodes and the common node.

Abstract: A gas discharge lamp ballast comprises a load circuit including circuitry for connection to a gas discharge lamp. A circuit supplies d.c. power from an a.c. voltage. A d.c.-to-a.c. converter circuit is coupled to the load circuit for inducing a.c. current therein. The converter circuit comprises first and second converter switches serially connected in the foregoing order between a bus node at a d.c. voltage and a reference node, and being connected together at a common node through which the a.c. load current flows. The first and second converter switches each have a control node and a reference node, the voltage between such nodes determining the conduction state of the associated switch. The respective control nodes of the first and second converter switches are interconnected. The respective reference nodes of the first and second converter switches are connected together at the common node.

Abstract: A ballast circuit for a gas discharge lamp comprises a resonant load circuit incorporating the gas discharge lamp and including a resonant inductance and a resonant capacitance. A d.c.-to-a.c. converter circuit induces an a.c. current in the resonant load circuit. The converter circuit comprises first and second converter switches serially connected in the foregoing order between a bus conductor at a d.c. voltage and a reference conductor, and being connected together at a common node through which the a.c. load current flows. The first and second converter switches comprise respective interconnected control nodes respective reference nodes interconnected together at a common node. The voltage between each control node and associated reference node determining the conduction state of the associated switch. A voltage-limited energy source is connected between first and second nodes.

Abstract: A gas discharge ballast circuit comprises a resonant load circuit including a resonant inductance, a resonant capacitance, and circuitry for connection to at least one gas discharge lamp. A d.c.-to-a.c. converter circuit is coupled to the load circuit for inducing an a.c. current in the circuit. It comprises first and second converter switches serially connected in the foregoing order between a bus conductor at a d.c. voltage and a reference conductor, and connected together at a common node through which the a.c. load current flows. The first and second converter switches each comprise a control node and a reference node, the voltage between such nodes determining the conduction state of the associated switch. The respective control nodes of the first and second converter switches are interconnected. The respective reference nodes of the first and second converter switches are connected together at the common node.

Abstract: A ballast for an electrodeless gas discharge lamp comprises a load circuit including an r.f. inductor for generating an r.f. field for powering the electrodeless lamp and a serially connected resonant capacitance. The inductance of the r.f. inductor has a substantial effect in determining a frequency of resonance the load circuit. A d.c.-to-a.c. converter circuit is coupled to the load circuit for inducing a.c. current therein. It comprises first and second converter switches serially connected in the foregoing order between a bus node at a d.c. voltage and a reference node, and being connected together at a common node through which the a.c. load current flows. The first and second converter switches each has a control node and a reference node, the voltage between such nodes determining the conduction state of the associated switch. The respective control nodes of the first and second converter switches are interconnected.

Abstract: A ballast circuit for a gas discharge lamp contained within a resonant load circuit has resistively heated cathodes. A d.c.-to-a.c. converter circuit supplyies a.c. current to the resonant load circuit. The converter circuit comprises first and second switches serially connected between a bus conductor at a d.c. voltage and a reference conductor, and has a common node through which the a.c. current flows. In an arrangement for controlling the converter switches, a comparator circuit compares a signal on a first input node with a periodic reference signal on a second input node, and produces a comparator output signal that changes state when a first one of the compared signals becomes greater than the second of the compared signals, and that further changes state when the second of the compared signals then becomes greater than the first of the compared signals. A circuit generates the periodic reference signal in response to the comparator output signal.

Abstract: Disclosed is a ballast circuit for a gas discharge lamp comprising a resonant load circuit incorporating the gas discharge lamp, a resonant inductance, and a resonant capacitance. A d.c.-to-a.c. converter circuit induces an a.c. current in the load circuit, and comprises first and second converter switches serially connected in the foregoing order between a bus conductor at a d.c. voltage and a reference conductor. The switches are connected together at a common node through which the a.c. load current flows. The switches each have a control node and a reference node, the voltage between such nodes determining the conduction state of the associated switch. The respective control nodes of the switches are interconnected, and the respective reference nodes of the switches are connected together at the common node.

Abstract: An electrodeless fluorescent lamp having an emission suppression arrangement utilizing a capacitive filtering element formed by a first conductive layer disposed on a portion of the interior surface of the lamp envelope, a second conductive layer on a corresponding external portion of the lamp envelope and the glass material of the lamp envelope disposed therebetween, achieves significant emission reduction yet at the same time reduces eddy current losses otherwise occurring at the second conductive coating portion of the capacitive filtering element. A plurality of slots formed in the second conductive coating are effective so as to reduce the circular flow of eddy currents around the second conductive layer, such eddy currents as would otherwise adversely affect the Q of the circuit.

Abstract: A ballast circuit for a gas discharge lamp comprises a resonant load circuit incorporating the gas discharge lamp and including a resonant inductance and a resonant capacitance. A d.c.-to-a.c. converter circuit induces an a.c. current in the resonant load circuit. The converter circuit comprises first and second switches serially connected between a bus conductor at a d.c. voltage and a reference conductor, and which are connected together at a common node through which the a.c. load current flows. The first and second switches each comprise a control node and a reference node, the voltage between such nodes determining the conduction state of the associated switch. The respective control nodes of the first and second switches are interconnected. The respective reference nodes of the first and second switches are connected together at the common node.