Patent ID: 8076865
Filing Date: 2011-12-13
Classification: H05B,Y02B

Abstract:
1. A method of controlling an oscillator of a high frequency ballast driving a metal halide lamp comprising: receiving power from an alternating current (AC) power supply; converting the received power to direct current (DC) power wherein the converted DC power is provided to the controller of the ballast; initializing a controller of the ballast in response to receiving the DC power at the controller; closing a power supply loop of the oscillator via a switch, said power supply loop including the converted DC power and a ground path, wherein the oscillator generates AC power from the converted DC power and provides the generated AC power to the lamp when the power supply loop is closed; monitoring a current of the power supply loop of the oscillator; and open circuiting the power supply loop of the oscillator via the switch when the monitored current is above a current threshold, said current threshold indicating that the lamp has not ignited; providing an ignition pulse train to the lamp for a first period, wherein providing the ignition pulse train comprises: repeating the above if the lamp has not ignited; and upon conclusion of the additional cooling period, providing a second ignition pulse train to the lamp for a second period; thereafter determining whether the lamp has ignited; thereafter detuning an inductor of the oscillator for a sleep period if said determining indicates that the lamp has not ignited.