| 摘要 |
PROBLEM TO BE SOLVED: To reduce current consumption as compared with the parallel driving of plural LEDs by driving the LEDs in series. SOLUTION: When data are written in a latch 70, a transistor(TR) switch 72 connected to the output of a bit of which value is '1' is turned on, a current from a constant current source 73 is allowed to flow into the TR switch 72 turned to the ON state and is not allowed to flow into its corresponding LED 71. Thereby the LED 71 is not turned on. On the other hand, a TR switch 72 connected to the output of a bit of which value is '0' is turned off and a current from the constant current source 73 is not allowed to flow into the TR switch 72 turned to the OFF state but is allowed to flow into its corresponding LED 71. Thereby the LED 71 is turned on. |
