| 摘要 |
<p>A ballast circuit is disclosed which includes an inverter for generating an alternating voltage comprising at least one switching element, a load circuit coupled to the inverter and comprising terminals for lamp connection, a driving circuit coupled to the switching element for generating a driving signal for rendering the switching element alternately conducting and non-conducting, a measuring circuit coupled to the load circuit and the driving circuit for generating a first signal that is a measure for a current flowing in the load circuit. In accordance with the invention the driving circuit further comprises phase-shifting circuitry for generating a second signal that is phase shifted with respect to the first signal and in that the driving circuit comprises control means for controlling that the driving signal is substantially in phase with the second signal. Because of the phase shift between the first signal and the driving signal, capacitive operation is effectively avoided.</p> |
