General Electric Company

Harris Corporation

Kevin C Routh

Robert P Alley

William Hull Bicknell

Robert Louis Steigerwald

Glenn Scott Claydon

Thomas Andrew Jochum

A system includes an upper driver circuit connected between a first source of voltage and a first point of reference potential, for driving the gate of a first switching device having a main current path connected between a second source of operating voltage and the first point of reference potential. The system further includes a lower driver circuit connected between a third source of operating voltage and a second point of reference potential, for driving the gate of a second switching device having a main current path connected between the first and second points of reference potential. Detection circuitry is included for detecting a common-mode dv/dt induced signal to disable the sensing of valid 'ON' and 'OFF' signals by the upper circuit, to prevent false triggering of the upper circuit.

Level shift circuit with common mode rejection

An autonomous active clamp circuit clamps voltage across an inductive load. The clamp closes when the voltage across it exceeds some value substantially above peak line voltage, conducts with a low voltage drop, and opens when the current going through it reaches nearly zero.

Autonomous active clamp circuit

By monitoring line current before the lamps of a fluorescent lighting system start, an estimate of full load current is made. The estimate is used to adjust the current feedback gain to avoid any current level overflow in the control. The normalized values used within the control result in consistent relative light levels independent of load size.

Adjusting feedback gain in a fluorescent lamp dimming control

A digital data detector is part of the primary side control electronics in a high voltage integrated circuit for regulating a power supply secondary side output potential; the detector output is responsive to the transitions of digital error data received from the supply secondary side via an electrically-isolated data transmission means. Only the transition edges are utilized by the detector, so that any non-linearity after each transition of the transmission means is immaterial. If the isolation device is a pulse transformer, the transformer core can be of relatively small volume, as full-pulse reproduction is unimportant and pulse saturation is tolerable. A multiplexer allows the primary side control electronics to initiate power supply operation; control is switched to the secondary side responsive to signal edges therefrom being detected by the digital data detector.

HVIC power supply controller with primary-side edge detector

A fluorescent lamp dimming system which can be used in a retrofit manner with existing fluorescent lamp ballasts achieves a greater degree of energy management than has been previously possible. A dimming control having closed-loop feedback uses integrals of current as a measure of light output from the fluorescent lamps. The electronic control circuit implements complex control methods in a minimal space and at a minimal cost.

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Schenectady, NY, United States of America

Kevin C Routh