| 摘要 |
<p>A triac dimmable electronic ballast having a single stage feedback power factor inverter configuration which prevents a DC bias from being applied to the resonant circuit current via a feedback path connecting the resonant circuit with the feedback node of the single stage power factor inverter. In one aspect of the present invention, a dimmable electronic ballast comprises: an input means for connecting to an AC power source; a triac switch for phase angle dimming the input AC power; a rectifier for full wave rectifying the AC power output from the triac to provide DC power; a DC coupling circuit having a feedback node associated therewith; a DC energy storage device, operatively connected to the full-wave rectifier via the DC coupling circuit, for storing DC power; a half-bridge inverter circuit connected to the DC energy storage device for converting the stored DC power to high frequency power at an inverter frequency; a first DC blocking device; a resonance circuit, operatively connected to the half-bridge inverter via the first DC blocking device; for coupling the high frequency power to a load; feedback connection means connecting the resonant circuit to the feedback node of the DC coupling circuit, for providing high frequency power to the energy storage device; and a second DC blocking device, operatively connected to the feedback connection means, for preventing DC signals from being applied to the resonant circuit through the feedback connection means.</p> |
