| 摘要 |
PROBLEM TO BE SOLVED: To make light emitting diodes emit light enough for photographic lighting by using a battery power source of nominal 3 V. SOLUTION: The battery power source BP1 is connected to the power input terminal Vin of a voltage boosting circuit VP1 and a source voltage of nominal 3 V is applied on the terminal Vin. When a switch SW1 which turns on and off associatively with the opening/closing operation of a shutter turn on, clock signalsϕ1 andϕ2 are applied from a clock generating means CG1 to transistors Q1 and Q2. Then the transistors Q1 and Q2 turn on and off alternately to accumulate voltage in a 2nd capacitor C2 and voltage which is nearly twice as high as the source voltage is outputted from the boosted output terminal of the voltage boosting circuit VP1. To the boosted output terminal Vout, a white light emitting diode LW1, a blue light emitting diode LB1, and a green light emitting diode LG1 which have high forward voltages are connected in parallel to one another. A red light emitting diode LR1 which has a low forward voltage, on the other hand, is directly connected to the battery power source BP1. |
