Systel Development + Industries Ltd.

International Rectifier Corporation

Moshe Kalichstein

Daniel Rubin

Arie Lev

Yoel Sharaby

Rafael Mogilner

A programmable digital power controller for gas discharge devices such as fluorescent lamps or other devices using all digital internal and external programmable controls. A specific ASIC is described. A gate array and microcomputer share parallel functions with fast sub-functions carried out by the gate array and slower sub-functions carried out by a micro-processor. Circuits are provided for automatic shut down when a high frequency ground fault is detected; for connecting the filaments of multiple gas discharge devices in a series/parallel circuit in a manner that power for a particular device is disabled when that device is removed from the circuit; for driving the load as close to resonance as possible but in an inductive mode; and for developing a dead time between high side and low side switches which is related to transformer current, switch current, bridge voltage or bridge voltage dv/dt.

Digital power controller for gas discharge devices and the like

A power controller for fluorescent lamp dimming is disclosed, using all digital internal and external programmable controls. A specific ASIC is described. A gate array and microcomputer share parallel functions with fast sub-functions carried out by the gate array and slower sub-functions carried out by a micro-processor. Circuits are provided for automatic shut down when a high frequency ground fault is detected; for connecting the filaments of gas discharge lamps in a series/parallel circuit for driving the load as close to resonance as possible but in an inductive mode; and for developing a dead time between high side and low side switches which is related to transformer current, switch current, bridge voltage or bridge voltage dv/dt.

Apparatus for controlling operation of gas discharge devices

A method and apparatus for controlling a boost converter, which offers improved power factor correction by compensating for the distorting effects of parasitic capacitance and parasitic oscillations. By precise adjustments to the closing time of the boost switch, the effects of parasitic capacitance can be reduced or eliminated. A zero current detector capable of detecting both forward and reverse zero current points facilitates the compensation. The method and circuit of the present invention are well-suited to integration with an inexpensive digital controller such as a microprocessor, and a method of dithering to enhance the time resolution of clocked digital circuits is presented.

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Tel Aviv, Israel

Moshe Kalichstein