Circuit arrangement for operation of one or more lamps
AssigneeKoninklijke Philips Electronics N.V.
InventorsUlrich Böke, Antoon J. Bock
Life of this patent
Estimating the term…
Abstract
The invention relates to a background lighting system for a liquid crystal display, more particularly to an electronic circuit for operation of one or more discharge lamps. A DC/AC full-bridge inverter circuit generates two voltages whose AC components are phase-shifted by 180°. The discharge lamps are supplied with the sum of these two AC voltages.
Claims6
In a circuit for operating one or more low pressure gas discharge lamps, the circuit including a first half-bridge switching circuit having a first output and a second half-bridge switching circuit having a second output, the first half-bridge switching circuit operating substantially 180° out of phase from the second half-bridge switching circuit;
- characterized by a lamp drive circuit for each lamp, each lamp drive circuit comprising:
- a first resonant circuit having an input coupled to the output of said first half-bridge switching circuit and a first output adapted to connect to a first end of a low pressure gas discharge lamp;
- and
- a second resonant circuit having an input coupled to the output of said second half-bridge switching circuit and a second output adapted to connect to a second end of said low pressure gas discharge lamp.
In a circuit for operating one or more low pressure gas discharge lamps, the circuit including a full-bridge switching circuit in which alternate arms conduct simultaneously to produce a first square wave at a first output and a second square wave at a second output substantially 180° out of phase with the first square wave, characterized by a lamp drive circuit for each lamp, each lamp drive circuit comprising:
- a first resonant circuit having an input coupled to the first output and a first output adapted to connect to a first end of a low pressure gas discharge lamp;
- and
- a second resonant circuit having an input coupled to the second output and a second output adapted to connect to a second end of the low pressure gas discharge lamp.
Dependencies are inferred from the claim text.