Protective starting circuit for inverter operated gaseous discharge lamps
 A circuit arrangement for starting a linear metal halide arc discharge lamp while in a transistor switching bridge inverter circuit. A pulse generator is electrically connected to a trigger electrode which is mounted in close proximity to the lamp for supplying pulsed high voltage. The trigger electrode is capacitively coupled to the lamp for supplying pulsed high voltage for starting the lamp. A first logic gate is connected in circuit between a pulse width modulator and a phase splitter driver and is responsive to lamp current to lock the driver in a constant mode until the lamp starts. A second logic gate is connected to the pulse generator and is responsive to lamp current to inhibit the generator when the lamp is on. The pulse width modulator produces, when enabled, a variable pulse train having a fast rise and fall time. This variable pulse train is delivered to the phase splitter driver within which is developed the signal for driving the inverter. A differential amplifier is responsive to the differences in light sensed at opposite ends of the lamp and is connected to the pulse width modulator to control its operation. 
General Electric Company
H Y
H05B Y10S
inventional additional
James R.
Collins