Ballast having a dimming device
AssigneePatent-Treuhand-Gesellschaft fur elektrische Gluhlamplen mbH
InventorsKlaus Fischer, Josef Kreittmayr
Life of this patent
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Abstract
A ballast having a dimming device for a low-pressure discharge lamp. It has two technically different possibilities for controlling the lamp brightness. The first possibility for controlling the lamp brightness is by means of adjusting the amplitude of the lamp current. The second possibility for brightness control is based on the fact that the low-pressure discharge lamp can be operated with a pulsed lamp current. In particular, both operating modes are used in combination in specific brightness ranges.
Claims13
An electronic ballast having a dimming device for the purpose of controlling the brightness of a low-pressure discharge lamp by means of adjusting the amplitude of the lamp current,
- characterized in that the dimming device is also designed
- to operate the low-pressure discharge lamp by means of lamp current pulses having time intervals and to implement brightness control by adjusting the duty ratio between the pulse duration and the interpulse interval of the lamp current,
- to implement brightness control differently, firstly in a first brightness range and secondly in a further brightness range having a lower brightness than in the first brightness range,
- and to implement brightness control in the first brightness range at least also by means of adjusting the amplitude of the lamp current and., in the further brightness range, at least also by adjusting the duty ratio between the pulse duration and the interpulse interval of the lamp current.
A method for controlling the brightness of a low-pressure discharge lamp by means of an electronic ballast having a dimming device by controlling the amplitude of the lamp current,
- characterized in that the dimming device is also used
- to operate the low-pressure discharge lamp by means of lamp current pulses having time intervals and to control the brightness by controlling the duty ratio between the pulse duration and the interpulse interval of the lamp current,
- to implement brightness control differently, firstly in a first brightness range and secondly in a further brightness range having a lower brightness than in the first brightness range,
- and to implement brightness control in the first brightness range at least also by means of adjusting the amplitude of the lamp current and, in the further brightness range, at least also by adjusting the duty ratio between the pulse duration and the interpulse interval of the lamp current.
Dependencies are inferred from the claim text.