Method and Circuit for Driving a Gas Discharge Lamp

• US 20080303450A1
• Filed: 12/06/2006
• Published: 12/11/2008
• Est. Priority Date: 12/21/2005
• Status: Active Grant

• Current Assignee: Lumileds LLC (Apollo Global Management, Inc.)
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Luerkens, Peter
• Granted Patent: US 7,990,069 B2
• Time in Patent Office: Days
• US Class Current: 315/291
• CPC Class Codes: H05B 41/2883 the controlled element being a DC/AC converter in the final stage, e.g. by harmonic mode starting
• CPC Class Codes: H05B 41/2928 for protecting the lamp against abnormal operating conditions
• CPC Class Codes: Y02B 20/00 Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps

Abstract

The invention relates to a method for driving a gas discharge lamp and relates to a lamp driver circuit for driving a gas discharge lamp in accordance with said method. The method comprises supplying a current to the gas discharge lamp, reversing the direction of the current supplied to the gas discharge lamp and, substantially simultaneously, generating a relatively high voltage. The generated high voltage serves to prevent a series of re-ignitions of the gas discharge lamp that may lead to visible flickering of the gas discharge lamp or to extinction of the gas discharge lamp.

Claims

1. Method of driving a gas discharge lamp, the method comprising:

supplying a current to the gas discharge lamp, thereby generating an operating voltage over the gas discharge lamp;

reversing a direction of the current supplied to the lamp; and

applying a reversal voltage higher than the operating voltage to the gas discharge lamp substantially simultaneously with the step of reversing the current.

2. Method according to claim 1, wherein the reversal voltage is about twice the operating voltage.

3. Method according to claim 1, wherein the method comprises generating the reversal voltage by a resonant circuit.

4. Method according to claim 1, wherein a maximum additional voltage over the lamp occurs, when the current supplied to the lamp is substantially zero.

5. Lamp driver circuit for driving a gas discharge lamp, the driver circuit comprising:

a current source for supplying a current to the gas discharge lamp;

a commutation circuit operatively connected to the current source for reversing a direction of the current supplied to the gas discharge lamp;

an ignition circuit connectable to the gas discharge lamp for generating an ignition voltage suitable to ignite the gas discharge lamp; and

a reversal voltage generation circuit for generating a reversal voltage higher than an operating voltage to be applied to the gas discharge lamp substantially simultaneously with a reversal of the direction of the current.

6. Lamp driver circuit according to claim 5, wherein the reversal voltage generation circuit is a resonant circuit connected to an output of the current source.