Stablizing circuit for metal halide lamp

Abstract

Abstract PURPOSE: To operate a metal halide lamp without harmful electrophoresis and acoustic resonance function by applying high voltage to a pair of electrodes to excite gas, supplying the specified rectangular wave current to keep excitation, and periodically. alternately changing the current direction. CONSTITUTION: Voltage is supplied from a rectifier filter circuit 100 and a DC/DC step-up converter 500, current is supplied to a lamp starting circuit 700 from a DC/DC switching current adjuster 300 through an inverting bridge 400, and in order to keep a gas exciting state formed by applying high voltage, rectangular wave current of 0.2-2A, 1.0-0.1msec. is let to flow periodically reversely across the electrodes. A circuit 200 containing a clock generator and a pulse width modulator controls the inversing bridge 400 with a 7.68kHz signal, and controls a current adjuster with a 30.72kHz signal, receives a lamp current feedback signal, and performs pulse width modulation by controlling an immediatet photo current control circuit 600. By this constitution, undesirable actions are removed, and a metal halide lamp is stably operated.

Inventors

• 👤 Joseph M Allison
• 👤 ジョセフ・マイケル・アリソン
• 👤 Richard L Hansler
• 👤 リチャード・ローウェル・ハンスラー
• 👤 Park French
• 👤 パーク・フレンチ
• 👤 John M Davenport
• 👤 ジョン・マーティン・ダベンポート
• 👤 Robert A Leskovec
• 👤 ロバート・アンソニー・レスコベク

Bibliographic Details