Method and circuit for driving a gas discharge lamp
First Claim
Patent Images
1. A method of driving a gas discharge lamp, the method comprising the acts of:
- igniting the gas discharge lamp using ignition pulses having an ignition frequency;
after ignition of the gas discharge lamp, operating the gas discharge lamp at an operating voltage by supplying a current to the gas discharge lamp, thereby generating the operating voltage over the gas discharge lamp;
after the ignition and removal of the ignition pulses, reversing a direction of the current supplied to the gas discharge lamp at an operating frequency which is lower than the ignition frequency to reverse the operating voltage at the operating frequency; and
after the ignition and the removal of the ignition pulses, applying at the operating frequency a reversal voltage higher than the operating voltage to the gas discharge lamp substantially simultaneously with the reversing act.
6 Assignments
0 Petitions
Accused Products
Abstract
A method for driving a gas discharge lamp and relates to a lamp driver circuit for driving a gas discharge lamp. The method includes 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.
-
Citations
10 Claims
-
1. A method of driving a gas discharge lamp, the method comprising the acts of:
igniting the gas discharge lamp using ignition pulses having an ignition frequency; after ignition of the gas discharge lamp, operating the gas discharge lamp at an operating voltage by supplying a current to the gas discharge lamp, thereby generating the operating voltage over the gas discharge lamp; after the ignition and removal of the ignition pulses, reversing a direction of the current supplied to the gas discharge lamp at an operating frequency which is lower than the ignition frequency to reverse the operating voltage at the operating frequency; and after the ignition and the removal of the ignition pulses, applying at the operating frequency a reversal voltage higher than the operating voltage to the gas discharge lamp substantially simultaneously with the reversing act. - View Dependent Claims (2, 3, 4, 5, 6)
-
7. A 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 ac ignition pulses suitable to ignite the gas discharge lamp, the ignition pulses having an ignition frequency, wherein the ignition circuit is configured to stop providing the ignition pulses after ignition of 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, wherein the reversal voltage generation circuit is configured to provide the reversal voltage after the ignition and removal of the ignition pulses, the reversal voltage having an operating frequency which is lower than the ignition frequency to reverse the operating voltage at the operating frequency. - View Dependent Claims (8, 9, 10)
-
Specification