| 摘要 |
PROBLEM TO BE SOLVED: To provide a power supply method having stability and flexibility in power control, capable of switching the pulse current to be supplied to a light source used by a projector in accordance with situation, a power supply circuit, and a projector. SOLUTION: The power supply circuit 1 is equipped with an amplifying circuit (a variable amplifying means) 142 for amplifying a reference electric power P<SB>S</SB>, outside a current control means which performs feed-back control of output current so as to make a detected current I<SB>L</SB>detected by a current detection means 107 a target current I<SB>R</SB>; and with an electric power calculation circuit (a calculating means) 143 for generating the target current I<SB>R</SB>by dividing the amplified electric power by the detected voltage V<SB>L</SB>detected by a voltage detection means 106. The power supply circuit 1 supplies the pulse current to the light source 22 when the amplifying circuit 142 changes its amplifying rate. The changes in circuit characteristics by treatments in the amplifying circuit 142 and the electric power calculating circuit 143, and effects provided to a feed-back control caused by the occurrences of dead time or the like, are suppressed to stabilize the electric power control in the power supply circuit 1. COPYRIGHT: (C)2007,JPO&INPIT
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