Osram Sylvania Inc.

Ayan Choudhury

Shashank Bakre

Arindam Chakraborty

Nitin Kumar

Markus Ziegler

Joseph Parisella

Driss Baba

A multi-strike ballast to ignite an electrodeless lamp is disclosed, and includes an inverter circuit, a protection circuit, and a controller. The inverter circuit, upon activation, sends an ignition pulse to the lamp. The inverter circuit shuts down upon receiving a deactivation signal, and activates upon receiving an activation signal, triggering another ignition pulse. The protection circuit senses a change in a voltage associated with the lamp. The sensed changed may indicate that the lamp has not yet ignited or that the lamp is broken. The controller receives the sensed change in voltage and, in response, sends a deactivation signal to the inverter circuit. The controller waits a predetermined time and then sends an activation signal to the inverter circuit. The controller repeats until a change in voltage associated with the lamp is not sensed, or until a predefined number of repeats occur, providing multiple ignition pulses to the lamp.

Multiple strike ballast with lamp protection for electrodeless lamp

A ballast comprises an inverter having a transformer comprising a core, a primary winding, and a secondary winding for connecting to a lamp and providing voltage thereto. The ballast includes a fault condition detection circuit connected to the inverter for disabling the inverter to discontinue energization of the lamp when a fault condition occurs. The fault condition detection circuit comprises an other primary winding wound on the core of the transformer for receiving a voltage signal proportional to a voltage across the secondary winding, a voltage blocking circuit connected to the other primary winding for receiving the voltage signal from the other primary winding, and a capacitor connected between the voltage blocking circuit and ground potential. The voltage blocking circuit is configured to selectively conduct and block the received voltage signal as a function of the frequency of the received voltage signal.

Fault condition of detection circuit

A ballast comprises an inverter circuit for connecting to a lamp and providing power thereto. The ballast includes a current feedback circuit connected to the inverter circuit and the lamp for controlling the frequency of the inverter circuit based on current feedback from the lamp. The ballast includes a switch circuit connected to the current feedback circuit and the lamp for enabling the current feedback circuit when the lamp is in a normal operating state and disabling the current feedback circuit when the lamp is in a low current operating state.

Switch circuit for a ballast

An arc detection circuit that detects an occurrence of arcing between ballast and a lamp is provided. A transformer has a primary side connected between the ballast and the lamp to receive lamp current and conduct the lamp current from the ballast to the lamp during normal operation. A secondary side of the transformer produces a transformer voltage as a function of the lamp current received by the primary side. The produced transformer voltage is less than a threshold value during normal operation and greater than the threshold value during an occurrence of arcing between the ballast and the lamp. The arc detection circuit reduces the produced transformer voltage and provides it to the ballast so as to shut down the ballast operation.

Ballast with an arc quenching circuit

A multi-strike ballast to ignite an electrodless lamp is disclosed, and includes an inverter circuit, an output voltage detection circuit (OVDC), and an inverter shutdown circuit. The inverter circuit, upon activation, sends an ignition pulse to the electrodeless lamp. The inverter circuit shut downs upon receiving a deactivation signal, and activates upon receiving an activation signal, triggering another ignition pulse. The OVDC detects an output voltage across the lamp. The inverter shutdown circuit includes a multi-strike diac and receives the detected output voltage. The multi-strike diac breaks upon the output voltage reaching a predetermined level. In response, a deactivation signal is sent to the inverter circuit. The multi-strike diac turns off upon the output voltage falling below the predetermined level. In response, an activation signal is sent to the inverter circuit, triggering a further ignition pulse. The process repeats, providing multiple ignition pulses to the lamp.

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Danvers, MA, United States of America

Ayan Choudhury