Electro-mag International, Inc.

Other

Motorola Corporation

Pacific Scientific Company

Pacific Scientific

Northern Telecom Limited

Valmont Industries, Inc.

Magnetek, Inc.

Motorola Lighting, Inc.

Mihail S Moisin

Mark E Martich

John G Konopka

Andrew Bobel

Thomas W Turner

Bryce L Hesterman

Allan A Nostwick

Kent E Crouse

Antonio Marques

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.

Circuit having EMI and current leakage to ground control circuit

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.

Circuit having power management

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.

Circuit having clamped global feedback for linear load current

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.

Circuit having global feedback for promoting linear operation

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.

Ballast circuit having enhanced output isolation transformer circuit with high power factor

Ballast circuit having enhanced output isolation transformer circuit

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.

Converter/inverter full bridge ballast circuit

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. When one of the lamps is removed, flux is no longer canceled so that a strike voltage is generated at the lamp terminals from which the lamp was removed.

Ballast instant start circuit

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.

Ballast circuit with independent lamp control

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.

HID ballast with hot restart circuit

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.

Ground fault protection circuit

A ballast circuit for energizing a lamp includes an inverter circuit with a start up circuit which provides a repeating start up sequence until a lamp lights. The start up circuit includes a start up switching element coupled across a start up capacitor which initiates operation of the inverter. A rapid start capacitor is charged as the inverter applies a signal to the lamp and the voltage on the rapid start capacitor determines the conduction state of the start up switching element. The inverter applies an increasing strike voltage to the lamp until the lamp lights or until the lamp voltage becomes greater than a predetermined level. After the restart capacitor discharges, the start up capacitor charges to re-initiate operation of the inverter. The ballast thereby applies a strike voltage to the lamp having a relatively small duty cycle for reduced stress on the circuit components.

Ballast circuit with controlled strike/restart

A ballast circuit for energizing a lamp includes an inductive element coupled to an input terminal and a capacitive element coupled to the inductive element in parallel with the lamp. In one embodiment, the capacitive element includes a plurality of capacitors each of which is coupled in series with a switch to control the total capacitance provided by the capacitors. By controlling the total capacitance, the intensity of light emitted by the lamp can be selected. In another embodiment, a switching element is coupled across one of the capacitors for providing a selected capacitance to the circuit for controlling the lamp light intensity. In a further embodiment, a transformer has a first winding coupled in series with the capacitive element with the inductive impedance of the first winding being controlled via a second transformer winding coupled to a control circuit. In another embodiment, a ballast circuit includes a transformer for introducing a series current into the circuit for subsequent detection by a detection circuit. This arrangement can be used to send a data signal from one point in the circuit to another which can be used to determine a lamp fight intensity level.

Ballast power control circuit

A ballast circuit for energizing a lamp comprises a circuit for limiting and/or regulating signal levels to the lamp. In one embodiment, the ballast comprises a control circuit which regulates the lamp current to a predetermined level such that the ballast can drive lamps having a predetermined diameter, which determines the operating current, and having a length that can vary, which determines the voltage drop across the lamp. In another embodiment, the ballast comprises a threshold circuit for limiting a load current prior to striking the lamp as well as after the lamp conducts current.

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Brookline, MA, United States of America

Mihail S Moisin