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1. 发明专利

JPH06152390A SEMICONDUCTOR INTEGRATED CIRCUIT 失效
公开(公告)号：JPH06152390A
公开(公告)日：1994-05-31
申请号：JP30212292
申请日：1992-11-12
申请人： TOSHIBA CORP , TOSHIBA MICRO ELECTRONICS
发明人： NIO RYOICHI , KURODA TADASHI
IPC分类号： H03B5/06 , H03B5/32 , H03L3/00
摘要： PURPOSE:To make it possible to oscillate also a crystal oscillation circuit whose oscillation start voltage becomes higher than battery voltage due to manufacturing dispersion and to improve the yield of the circuit by providing a semiconductor integrated circuit with a boosting circuit and an oscillation circuit. CONSTITUTION:When the generation of a clock pulse is started in a frequency dividing circuit 13, an oscillation detecting circuit 16 detects the pulse generation and supplies a detection signal to a timer circuit 17. The circuit 17 counts up time necessary for stabilizing the output voltage V2 of the boosting circuit 15 and inverts the logical level of a timer signal from 'H' to 'L'. A power supply switching circuit 11 switches boosting voltage V2 to battery voltage V1 and outputs the voltage V1 to the crystal oscillation circuit 10. The oscillation starting voltage Vsta of the circuit 10 is 1.2V e.g. and the oscillation maintaining voltage of the circuit 10 having about 1.2V Vsta is about 1.0V, so that even when voltage supplied from the circuit 11 is dropped to about 1.5V corresponding to the V1, the circuit 10 can continuously oscillate.

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