IGNITER CIRCUIT OF HIGH INTENSITY DISCHARGE LAMP

摘要

PURPOSE: An igniter circuit of a high intensity discharge lamp is provided to light a lamp in a hot status by applying a voltage higher than 15kV to both terminals of the lamp. CONSTITUTION: A rectifier(110) rectifies an input alternating current power into a direct current power. A constant voltage section(120) improves a power-factor of the direct current power and boosts the direct current power. A flyback converter(130) switches and supplies the boosted voltage from the constant voltage section(120) suitable in a voltage of a lamp(170) to the lamp(170). The flyback converter(130) estimates a load impedance change of the lamp(170) and generates a voltage according to the load impedance change of the lamp(170). A drive IC(140) drives the constant voltage section(120) and the flyback converter(130). A first igniter(150) generates a discharge pulse to induce a first high voltage pulse in the lamp(170) when an output voltage of the flyback converter(130) is greater than a predetermined value. A second igniter(160) generates a discharge voltage pulse to induce a second high voltage pulse in the lamp(170) when an output voltage of the flyback converter(130) is greater than a predetermined value.