| 摘要 |
<p>PURPOSE: To improve processing efficiency by avoiding transfer of information on lighting and non-lighting to an LED for which the transfer of the information on the lighting and non-lighting is not necessary. CONSTITUTION: A shift register 21 for converting lighting information of an LED from a serial signal into a parallel signal, a latch circuit array 22 for temporarily storing the parallel output of the shift register 21, and a driver array 23 for driving the LED of an LED array 24 so as to light in accordance with the output of the latch circuit array 22 are provided. To the shift register 21, a signal 25 for commanding lighting and non-lighting of the LED and a synchronous signal 26 are inputted. To the latch circuit array 22, a latch signal 27 for storing the output of the shift register 21 in the latch circuit array 22 is inputted. A differentiating circuit 42 to which the latch signal 27 is to be inputted is provided. The output of the differentiating circuit 42 is connected to a reset input of a D type flip-flop constituting the shift register 21. The differentiating circuit 42 detects a transition of the latch signal 27 from L to H so as to generate a pulse of L level for a fixed time.</p> |
