| 摘要 |
PROBLEM TO BE SOLVED: To reduce reactive power due to voltage conversion even in the case of a change in a light emission current (driving current) flowing in a light emission unit such as an LED and a light emission time.SOLUTION: A first step-up unit 110 performs voltage conversion on voltage of a battery 100 for charging main capacitors 102 and 104. A second step-up unit 112 steps up voltage according to electrical energy accumulated in the main capacitors to obtain a step-up control voltage. A current control unit 114 receives application of the step-up control voltage, and controls a driving current supplied to an LED 108 on the basis of a light emission amount and a light emission time under control of a logic circuit 116. At that time, the logic circuit controls the second step-up unit on the basis of the driving current to adjust the step-up control voltage. |
