The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Feb. 20, 1996
Filed:
Jan. 17, 1995
Wolfram Sowa, Munich, DE;
Christoph Kreutner, Herrsching, DE;
Abstract
To provide for dimmer operation of a fluorescent lamp (L) with a minimum of circuit components, the d.c. output level at an output terminal (C1) of an energy supply source, such as a switched mode power supply (10, 10'), is controlled in accordance with the setting of a dimmer control (D). The voltage level at the output capacitor (C1) of the switched mode d.c. power supply furnishes supply voltage for an inverter (T1, T2) coupled to the discharge lamp. During lamp operation, a control unit (R) controls the level of the d.c. voltage supply for the inverter in accordance with the dimmer setting. This permits change of the brightness of the fluorescent lamp (L) in a range of from 5% to 100% of nominal value. Preferably, control of the supply voltage for the inverter is activated only upon occurrence of the ignition or arc-over phase, for example under control of a timing circuit (ZS), controlling a relay in the preheating circuit of the lamp. The system has the advantage that the lamp does not fire or ignite at full power level but only at the power level controlled by the dimmer (D).