CIRCUIT ARRANGEMENT

摘要

A dimming ballast for use with a phase control dimmer, and particularly a triac dimmer, includes an EMI filter selected with a high impedance to avoid excessive voltage and peak currents in the filter due to resonance with the phase controlled AC waveform at low conduction angles, when the load presented by the lamp is low. The ballast also includes a DC-DC-converter of the switched mode type that keeps the EMI filter loaded and prevents misfiring of the triac dimmer and thereby flickering of a lamp operated with the dimming ballast.