JPS5466038A - Display unit - Google Patents

Abstract

PURPOSE: To eliminate the application of a high voltage to an electrode, and to prevent the deterioration in life of the electrode and its burning, by providing an external clock supervisory circuit and internal clock generating circuit and by operating the internal clock circuit while the external clock circuit is stopping.

CONSTITUTION: External clock signal 8 is inputted to supervisory circuit 2, whose output is inputted to AND circuit 4 of control circuit 20. The other output of supervisory circuit 2 is inputted to AND circuit 5 together with clock signal 9 from internal clock generating circuit 3, and outputs of AND circuits 4 and 5 are inputted to OR circuit 6, whose output is inputted as clock signal 12 to display part 7. When detecting the stop of external signal 8, supervisory circuit 2 sends out control signal 11, which is AND-ed by AND circuit 5 with internal signal 9 of internal generating circuit 3 to output clock signal 12, thereby operating display part 7 positively. Consequently, the continuous application of a high voltage to the electrode can be prevented.

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