| 摘要 |
<p>PURPOSE:To surely prevent an electrically writable and erasable memory from being rewritten at the time of power-ON or power-OFF operation as to a circuit equipped with the electrically writable and erasable memory. CONSTITUTION:This circuit is equipped with plural voltage monitoring circuits 3, 5,... which forcibly set the memory 1 in a read state when a source voltage Vcc is within a specific voltage monitor range which is lower than a rated voltage and higher than a ground voltage at the time of the power-ON operation and power-OFF operation, and the voltage monitoring ranges of the voltage monitoring circuits 3, 5,... are made different overlapping with one another. Therefore, the voltage monitoring range can substantially be widened, the memory 1 can surely be held in the read state at the time of the power-ON operation and power-OFF operation, and consequently the memory 1 can surely be prevented from being rewritten in a transition state of the source voltage.</p> |
