| 摘要 |
<p>A lamp ballast includes an inverter circuit, a resonant circuit, a control circuit, and a startup circuit. When the DC bus reaches its final value, a capacitor in the startup circuit charges to a predetermined voltage, at which point a pulse is sent to start a gate drive circuit in the inverter. Additionally, a gate in the control circuit is initially OFF, allowing full power to the lamp, and a capacitor in the control circuit charges to a predetermined voltage, at which point a gate is turned ON. When the gate is ON, power to the lamp is reduced. The control circuit capacitor is selected so that it charges for a sufficient period to allow the lamp to complete a glow phase of startup before turning on the gate and reducing power as the lamp transitions into an arc phase.</p> |
