| 摘要 |
<p>PURPOSE: To provide the power-ON resetting circuit which can securely initialize a synchronous circuit part and an asynchronous circuit part. CONSTITUTION: The power-ON resetting circuit which activates a power-ON reset signal when the power source is turned ON and inactivates it a specific time later is equipped with a clock detecting circuit 2 which outputs a clock detection signal PORC when one or >=2 clock signals CK are detected after the power source is turned ON; and the power-ON reset signal POR is activated at least until the clock detecting circuit 2 outputs the clock detection signal PORC. The clock detecting circuit 2 is provided preferably with an integration circuit which integrates the clock signal CK and a threshold circuit which outputs the clock detection signal when the integration output of the integration circuit exceeds a specific threshold value. In another way, the clock detecting circuit 2 is equipped with a counter circuit which is initialized when the power source is turned ON and outputs the clock detection signal PORC by counting a specific number of subsequent clock signals CK.</p> |
