| 摘要 |
<p>PROBLEM TO BE SOLVED: To reduce the power consumption of a micro computer applying voltage boosted based on the output of a ring oscillation circuit to N-MOS of high withstand voltage or middle withstand voltage, which is connected to an output terminal. SOLUTION: When the oscillation frequency of an oscillation circuit 17 becoming the system clock of a micro computer is higher than the oscillation frequency of a ring oscillation circuit 9, '0' is applied to an outer terminal and the output of the ring oscillation circuit 9 is supplied to a boosting circuit 6 from a switch circuit 20. When the oscillation frequency of the oscillation circuit 17 is lower than the frequency of the ring oscillation circuit 9, '1' is applied to the outer terminal and the oscillation of the ring oscillation circuit 9 is stopped. Then, the output of the oscillation circuit 17 is supplied to the boosting circuit 6 by the switch circuit 20. Thus, power consumption can be reduced by stopping the operation of the ring oscillation circuit 9.</p> |
