| 摘要 |
PURPOSE:To facilitate light emission in a short time even after a long suspension time of a driving current by providing a bias circuit which applies a predetermined voltage to a light emitting diode. CONSTITUTION:(A) denotes a signal waveform given to the input terminal 2 of an LED driving circuit 1 and (B) denotes a voltage applied to an LED 3 when the input signal is given to the terminal 2. The section (a) is the end of the signal composed of continuous alternation of 0 and 1. The level of 0 is continued for a long time in the section (b) and the signal composed of continuous alternation of 0 and 1 is started again in the section (c). As the LED 3 is biased by a bias circuit 4, the level of, for instance, -0.6 volts is maintained. Therefore, if the signal 1 is inputted in the section (c), the voltage applied to the LED 3 reaches the voltage -1.2 volts, necessary for starting light emission in a short time. With this constitution, even if the first rising pulse in the section (c) is short, sufficient light emission can be achieved. |
