Patent ID: 7348737
Filing Date: 2008-03-25
Classification: H05B,Y10S

Abstract:
1. A lighting circuit for a high-pressure discharge lamp used as a light source of a projector, comprising: a DC/DC converter that boosts a direct-current voltage and outputs the boosted direct-current voltage; an AC/DC converter that rectifies an alternating-current voltage to output a direct-current voltage; an input switch circuit and a power switch circuit that switch between the DC/DC converter and the AC/DC converter; a ballast circuit that stabilizes the lighting of said high-pressure discharge lamp; a power control section that controls the power supply from said ballast circuit to said high-pressure discharge lamp; a lighting initiation circuit that starts lighting of said high-pressure discharge lamp; and the high-pressure discharge lamp, wherein said power switch circuit performs power switching in such a manner that a first power is supplied to said high-pressure discharge lamp when a direct-current power supply is connected only to said DC/DC converter, and a second power higher than said first power is supplied to said high-pressure discharge lamp when an alternating-current power supply is connected to said AC/DC converter.