Title:
【発明の名称】高圧放電ランプを動作し点灯する方法と当該方法を実施するための回路
Document Type and Number:
Japanese Patent JPH09510046
Kind Code:
A
Abstract:
A method for detecting arc instabilities in a gas discharge lamp by evaluating the deviations of an electrical parameter of the lamp. A method suitable for detecting frequencies at which acoustic resonance induced instabilities occur evaluates the deviations measured over a range of frequencies. Selection of an operating frequency to avoid acoustic resonance is based on an evaluation of the deviations, such as the frequency at which the lowest standard deviation occurs for the electrical parameter measured. Favorably, the electrical parameter used is the conductivity, which provides high insensitivity to noise, is independent of ballast topology, and enables detection of acoustic resonance at levels not visible to the human eye. A control scheme tracks acoustic resonance during run-up of the lamp and quickly selects a favorable operating frequency after the lamp reaches steady-state. Resonance detection is achieved both during run-up and the steady state substantially without inducing visible flicker. The method and ballast employ universal techniques suitable for operating HID lamps of different types, wattages and manufacturers despite the occurrence of acoustic resonance/arc instabilities among these lamps over a fairly broad frequency range.
Inventors:
Holt Slack Antonius Hendricus Maria
Application Number:
JP52032996A
Publication Date:
October 07, 1997
Filing Date:
December 08, 1995
Export Citation:
Assignee:
Philips Electronics Nemrose Fennaught Shap
International Classes:
H05B41/292; H05B41/282; (IPC1-7): H05B41/29
Attorney, Agent or Firm:
Masao Sawada