| 摘要 |
PURPOSE:To detect improper lighting caused by the failure of an LED itself, by installing a means capable of simultaneously controlling all LED's in the lighting state, in response to an external command. CONSTITUTION:Lighting control signals 110-130 in the normal operating state are applied to one inputs of and gates 11-13, respectively. Reset signal 300 from the outside is commonly applied to the other inputs. The reset signal 300 is at a low level, so that the lighting state of each of the and gates 11-13 is controlled in response to the corresponding drive control signals 110-130. When the reset signal 300 turns to high level, all of the outputs 210-230 of the and gates 11-13 are compulsorily set at low level. Thereby all LED's 21-23 are driven in the lighting state, and the state of the LED's can be discerened at a glance. |
