Philips Electronics North America Corporation

Koninklijke Philips Corporation N.v.

North American Philips Corporation

Patrick E Troy

Kurt W Wicklund

Glenn D Garbowicz

Janis L Wetterich

A threshold detector for detecting lamp voltage includes an opto-coupler. The opto-coupler includes a radiation-emitting semiconductor element coupled to a source of a sensed voltage and an optically-coupled radiation-receiving semiconductor element with an impedance which varies with received radiation. A switching element coupled to the radiation-receiving semiconductor element produces a first or second signal, depending on the sensed voltage.

Lamp-voltage threshold detector

Starting of a gaseous discharge lamp is control led in response to both lamp voltage and duration of time during which igniting pulses are applied. An upper and a lower threshold voltage are utilized to determine whether the lamp is in an unstable starting mode, a cold starting mode, or a steady-state operating mode.

Multiple-parameter control of lamp ignition

A ballast for powering a fluorescent lamp with filaments requiring preheating. Control circuitry within the ballast delays an ignitor from being turned on until the filaments have been sufficiently preheated. The control circuitry is isolated and thereby protected from the high voltage pulses of the ignitor by an optocoupler. A SIDAC employed in the generation of the high voltage pulses is not relied upon for sensing full arc discharge of the lamp. The breakover voltage of the SIDAC can therefore be set at a much lower than conventional level resulting in the generation of more high voltage pulses over a prefixed period of time.

Ballast scheme for a fluorescent lamp with preheated filaments

A bi-level control system includes a plurality of slave units, each for connection to a respective ballast and HID lamp of a plurality of HID lighting fixtures, and a common control unit. Each slave unit includes a switched capacitor and a slave relay which has one input connectable to a common line of an AC power supply branch circuit powering the fixtures and another input adapted for receiving a line voltage signal. The control unit includes an output connected to the control inputs of each of the slave units by a single control line and switchably connected to line voltage. Dimming of the HID lamp is accomplished by switching line voltage to the output of the control unit which causes the slave relay to switch the slave capacitor into circuit with the HID lamp and ballast. Use of a single control line connecting each of the slave units to the control unit greatly reduces wiring over known systems. The control unit is also adapted to receive a control input from a sensor via a single input line, further reducing wiring.

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Chicago, IL, United States of America

Patrick E Troy