| 摘要 |
PROBLEM TO BE SOLVED: To obtain a semiconductor device in which a minimum necessary reset period after power-on is surely set. SOLUTION: When a power-on reset signal bar POR is in an inactive state ("H"), a counter reset circuit 5 counts "H" rising frequency of an oscillation start signal REN, and outputs a count signal bar COUNT of the active state ("L") until reaching a predetermined frequency, and outputs a count signal bar COUNT of the inactive state ("H") when reaching the predetermined frequency. On the basis of "L"/"H" of the count signal bar COUNT, a control circuit 3 for an active voltage step-down circuit outputs an activation signal VACT of "L"/"H" to an active voltage step-down circuit 2. The active voltage step-down circuit 2 is controlled to be active/inactive according to "L"/"H" of the activation signal VACT, and generates in the active state an internal voltage step-down power source potential VDD which is set based on a reference voltage VREF. COPYRIGHT: (C)2006,JPO&NCIPI
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