| 摘要 |
Electronic ballast for a lamp, such as a gas discharge lamp, preferably for a fluorescent lamp LA, has an inverter connected with a DC voltage source Vbus, and a load circuit connected to the inverter. The load circuit comprises the lamp (LA) and a series resonance circuit L1, C1. The inverter is formed by two switches Q1, Q2 arranged in a half-bridge arrangement. The switches are alternatingly controlled by control circuit 1 during an ignition phase so that their switch-on time (Ton) is increased to reduce the control frequency. In the ignition phase the control circuit monitors an output parameter of the half-bridge to determine if ignition has occurred. The control circuit may monitor a current or voltage, or a frequency. |
