| 摘要 |
<p>The invention provides a circuit for synchronizing the ignition in electronic ballast discharge lamps, including a half-bridge output stage of the electronic ballast having an upper switch and a lower switch, the lower switch being connected to a common wire of a power supply, in which circuit a high voltage impulse for igniting the lamp is only generated when the lower switch is open, the circuit including a transformer including a first winding and a second winding magnetically coupled to each other, the second winding having a lower number of turns than the first winding; one lead of the first winding being connectable to an electrode of a discharge lamp and a second lead thereof being connectable to the common wire of the power supply; diode connected with its anode to one lead of the second winding and with its cathode to the junction between the upper and lower switches; a second lead of the second winding connected to a thyristor, the thyristor being connected to the first plate of a discharge capacitor and the second plate of the capacitor being connected to the common wire; whereby discharge current of the capacitor flows through the second winding only when the lower switch is open.</p> |
