| 摘要 |
The invention relates to a protective circuit in an electronic ballast used for feeding a low-pressure electric discharge lamp, particularly a fluorescent lamp. Said ballast consists of a DC supply, a highfrequency oscillator (1, 2), and inductor (7) connected between said oscillator (1, 2) and said lamp (8). A capacitor (15, 16; 11) is connected either on the same side with or on the opposite side to said inductor (7). The protective circuit according to the invention includes a detection circuit (30-37) of lamp rectification having its operation based on the monitoring of the lamp electrode voltage. When the monitored voltage increases above or decreases below a preset level, the protective circuit halts the operation of the oscillator (1, 2). <IMAGE> |
