| 摘要 |
PROBLEM TO BE SOLVED: To set a working voltage at a high level by avoiding continuous charging, and to reduce power consumption of a power supply circuit itself by decreasing a leakage current in a standby state. SOLUTION: An operation voltage of a white LED 16 is 4.2 V, so that charging of a capacitor 14 is carried out through a boosting circuit device 12 from a power supply 10 (for example, LIB) of 3.8 V. The white LED 16 is connected to a current controller 18 of 0.3 V drive voltage, and a voltage detection circuit 20 is connected to the current controller 18. The capacitor 14 is a low ESR capacitor which has a low resistance value per unit volume [≤0.05 (Ωcc)], and can be charged and discharged at a super-high rate with an irreducible minimum capacity. The voltage detection circuit 20 detects a start-up timing of a boosting circuit device 12, and operates the current controller 18 after the capacitor 14 is momentarily charged immediately before the operation of the white LED 16. COPYRIGHT: (C)2011,JPO&INPIT
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